imex user manual 2012

User's Guide

IMEX

Advanced Black Oil/Gas Reservoir Simulator

Version 2012

By Computer Modelling Group Ltd.

This publication and the application described in it are furnished under license exclusively to the licensee, for internal use only, and are subject to a confidentiality agreement. They may be used only in accordance with the terms and conditions of that agreement. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic, mechanical, or otherwise, including photocopying, recording, or by any information storage/retrieval system, to any party other than the licensee, without the written permission of Computer Modelling Group. The information in this publication is believed to be accurate in all respects. However, Computer Modelling Group makes no warranty as to accuracy or suitability, and does not assume responsibility for any consequences resulting from the use thereof. The information contained herein is subject to change without notice.

Copyright 1987-2012 Computer Modelling Group Ltd. All rights reserved.

The license management portion of this program is based on: Reprise License Manager (RLM) Copyright (C) 2006-2012, Reprise Software, Inc

IMEX uses Intel(R) Compilers.

IMEX, CMG, and Computer Modelling Group are registered trademarks of Computer Modelling Group Ltd. All other trademarks are the property of their respective owners.

Computer Modelling Group Ltd. Office #150, 3553 - 31 Street N.W. Calgary, Alberta Canada T2L 2K7

Tel: (403) 531-1300 Fax: (403) 289-8502 E-mail: [email protected]

Preface IMEX is CMG's new generation adaptive implicit-explicit black-oil simulator which includes features such as local grid refinement, comprehensive well management, pseudo-miscible option, volatile oil option, polymer flooding, horizontal wells, dual porosity/permeability, flexible grids, and many more. IMEX was developed to simulate primary depletion, coning, water, gas, solvent, and polymer injection in single and double porosity reservoirs. This User's Guide provides a step-by-step procedure for preparation of an input data set for this program. A tutorial section is provided as well as a set of appendices describing the underlying theory. Use of this User's Guide requires a basic knowledge of reservoir engineering and some exposure to reservoir simulation. Every attempt has been made in the preparation of this User's Guide to provide the user with all the necessary details. If questions arise, please contact:

Computer Modelling Group Ltd.

#150, 3553 31 Street N.W. Calgary, Canada

T2L 2K7 Telephone: (403) 531-1300 Fax: (403) 289-8502 E-mail: [email protected]

Confidentiality: All components of CMG technology including software and related documentation are protected by copyright, trademark and secrecy. CMG technology can be used only as permitted by your license from CMG. By the license, you have agreed to keep all CMG technology confidential and not disclose it to any third party. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic, mechanical, or otherwise, including photocopying, recording, or by any information storage/retrieval system, to any party other than the licensee, without the written permission of Computer Modelling Group. Corrections/Errors: CMG ENDEAVORS TO PRODUCE TECHNOLOGY OF THE HIGHEST QUALITY; NEVERTHELESS ERRORS OR DEFICIENCIES IN SUCH TECHNOLOGY ARE INEVITABLE. IF YOU FIND AN ERROR OR DEFICIENCY, YOU ARE REQUESTED TO PROVIDE DETAILS OF IT AND ILLUSTRATIVE DATA SET(S) TO CMG SUFFICIENT TO PERMIT CMG TO REPRODUCE THE ERROR OR DEFICIENCY. CMG SHALL ENDEAVOR TO REMEDY A DEFICIENCY IN A TIMELY MANNER AND SHALL PERIODICALLY REPORT TO YOU AS TO THE STEPS BEING TAKEN TO REMEDY THE DEFICIENCY. THE RESPONSE TIME FOR A DEFICIENCY MUST BE PRIORITIZED FOR THEIR GENERAL APPLICATION TO CMG MEMBERS AND WHETHER THEY FORM PART OF A CMG PROGRAM. CMG DOES NOT WARRANT THAT DEFICIENCIES WILL BE REMEDIED. Limited Liability: CMG does not warrant the accuracy or usefulness of the technology and software - Refer to your license.

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Contents

Introduction 1Important Changes between IMEX 2012.10 and IMEX 2011.10 ................................. 1Important Changes between IMEX 2011.10 and IMEX 2010.10 ................................. 5Important Changes between IMEX 2010.10 and IMEX 2009.10 ............................... 10Important Changes between IMEX 2009.10 and IMEX 2008.10 ............................... 13Important Changes Between IMEX 2008.10 and IMEX 2007.10 .............................. 15Important Changes Between IMEX 2007.10 and IMEX 2006.10 .............................. 17Important Changes Between IMEX 2006.10 and IMEX 2005.10 .............................. 21Important Changes Between IMEX 2005.10 and IMEX 2004.10 .............................. 25Important Changes Between IMEX 2004.10 and IMEX 2003.10 .............................. 27Important Changes Between IMEX 2003.10 and IMEX 2002.10 .............................. 29Important Changes Between IMEX 2002.10 and IMEX 2001.10 .............................. 32Important Changes Between IMEX 2001.10 and IMEX 2000.10 .............................. 36Important Changes Between IMEX 2000.10 and IMEX 1999.10 .............................. 39Important Changes Between IMEX 1999.10 and IMEX 98.05 .................................. 44Important Changes Between IMEX 98.05 and IMEX 98.00 ...................................... 48Important Changes Between IMEX 98.00 and IMEX 97.00 ...................................... 49Important Changes Between IMEX 97.00 and IMEX 96.00 ...................................... 54Important Changes Between IMEX 96.00 and IMEX 95.00 ...................................... 59Important Changes Between IMEX 95.00 and IMEX 94.00 ...................................... 63Important Changes Between IMEX 93.00 and 92.00 ................................................. 67Introduction to IMEX ................................................................................................. 71

Tutorial 75Introduction ................................................................................................................. 75Data Groups in the Keyword Input System ................................................................ 76How to Document Your Data Set ............................................................................... 77How to Do a Restart .................................................................................................... 78Controlling Contents of the Output File ..................................................................... 79Controlling Contents of the Graphics File (SR2) ........................................................ 80Describing Your Grid System ..................................................................................... 81Describing Refined Grid ............................................................................................. 83Using Dual Porosity/Dual Permeability ...................................................................... 84Input of Null Blocks ................................................................................................... 88Using the Aquifer Option (see Appendix G) .............................................................. 90

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Using the Pseudo-Miscible Option ............................................................................. 92Using the API Tracking Option .................................................................................. 93Using the Rock Compaction/Dilation Model Option ................................................. 94Using the Polymer Option ........................................................................................ 102Problems with Small Timesteps or Long Execution Times ..................................... 103Problems with Solver Convergence ......................................................................... 106Simulating a Gas-Water or Gas Reservoir ............................................................... 107Simulating a Gas-Water with Condensate Reservoir ............................................... 108Simulating a Tilted Water-Oil/Water-Gas Contact .................................................. 110Horizontal Wells....................................................................................................... 114Vertical Equilibrium Calculation ............................................................................. 115Defining Multiple PVT Regions .............................................................................. 119Defining Wells ......................................................................................................... 122Defining the Well Type ............................................................................................ 124How to Shut In a Well and Reopen It....................................................................... 125Voidage Replacement ............................................................................................... 127Using the Wellbore Model ....................................................................................... 128Operating and Monitoring Constraints ..................................................................... 130Definition of Well Indices within IMEX .................................................................. 132Input of Well Indices ................................................................................................ 134Stopping a Simulation Run ....................................................................................... 136Using Wildcards in Well Lists ................................................................................. 137Guidelines for Setting Up Well Data ........................................................................ 138Recurrent Data from Other Sections ........................................................................ 141Subsidence Output .................................................................................................... 143Parallel IMEX........................................................................................................... 145Using the Seawater Injection Option ........................................................................ 147Using the Scale Buildup Option ............................................................................... 148Simulating a Volatile Oil Reservoir ......................................................................... 150Using the Subdomain-Dual Permeability-Reinfiltration Model ............................... 151Modelling Non Darcy Flow in Hydraulic Fractures Accurately Using a Grid Based Approach ............................................................................................ 153Using the Fracture Clean-up Model ......................................................................... 159Using the Oil Wet Option ......................................................................................... 163Special Keywords for Advanced Users (SHIFT) ..................................................... 171Modelling Non Darcy Flow in Fractured Shale Gas Reservoirs .............................. 172The WATER_FIX Keyword .................................................................................... 185Introducing a Hydraulic Fracture in Recurrent Data ................................................ 186The Trapped Oil Hysteresis Option for Pcow and Krow (Oil-Water System) ............. 187

Keyword Data Entry System 195Introduction to Keyword System.............................................................................. 195Comments (Optional) ............................................................................................... 201Blank Lines (Optional) ............................................................................................. 202

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Scan Mode for Checking Errors ............................................................................... 203Include Files (Optional) ............................................................................................ 204Controlling Data File Listing (Optional) .................................................................. 205Controlling Data File Listing Using NOLISTLIM (Optional) ................................. 206Changing the Comment Indicator (Optional) ........................................................... 207Changing the Keywords by Using Translate Rules (Optional) ................................. 208Input of Grid Property Arrays ................................................................................... 209Entering Matrix Grid Properties ............................................................................... 211Entering Fracture Grid Properties ............................................................................. 212Entering Refined Grid Properties .............................................................................. 213J and K Direction Data from I Direction .................................................................. 214Constant Value Arrays .............................................................................................. 215Array Input in IJK Notation ...................................................................................... 216Array Input of Values that Vary in the I Direction ................................................... 218Array Input of Values that Vary in the J Direction ................................................... 219Array Input of Values that Vary in the K Direction ................................................. 220Values that Vary for Most or All Grid Blocks .......................................................... 221Modifying Array Data (Conditional) ........................................................................ 222Interpolating Table Data (Optional) .......................................................................... 225

Input/Output Control 227Command Line Input/Output Control ....................................................................... 227Values Stored in Binary Form .................................................................................. 231ASCII Characters ...................................................................................................... 233Input/Output File Names (Optional) ......................................................................... 234Important Notes (Run Time Dimensioning) ............................................................. 238Problem Type Where IMEX Fails to Allocate Adequate / Appropriate Storage .......... 239Run Time Dimensioning (Optional) ......................................................................... 240Background (Run Time Dimensioning) .................................................................... 245Advantages of Run Time Dimensioned IMEX ......................................................... 246Project Main Title (Optional) .................................................................................... 247Project Second Title (Optional) ................................................................................ 248Project Third Title (Optional) ................................................................................... 249Case Identification (Optional) ................................................................................... 250Check Only (Optional) .............................................................................................. 251Trap UNIX Signal 2 Interrupt (Optional) ................................................................. 252ASCII Form of SR2 (Optional)................................................................................. 254Precision of SR2 (Optional) ...................................................................................... 255Controlling Data File Listing Using NOLISTLIM (Optional) ................................. 256Input Data Units (Optional) ...................................................................................... 257Output Data Units (Optional) .................................................................................... 260Data Range Checking (Optional) .............................................................................. 261Maximum Number of Error Messages (Optional) .................................................... 262Restart Timestep (Optional) ...................................................................................... 263

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Restart Record Writing Frequency (Optional) ......................................................... 264Output Printing Frequency (Optional) ...................................................................... 266Items in Output Print File (Optional) ....................................................................... 269Simulation Results File Writing Frequency (Optional) ............................................ 276Items in Simulation Results File (Optional) ............................................................. 278Items in Diary File (Optional) .................................................................................. 284Production Split Output (Optional) .......................................................................... 286Debug Output (Optional) .......................................................................................... 287

Reservoir Description 291Fundamental Grid Definition (Required) ................................................................. 291K Direction Index (Optional) ................................................................................... 298Block Dimensions for the I Direction (Conditional) ................................................ 300Block Dimensions for the J Direction (Conditional) ................................................ 302Block Dimensions for the K Direction (Conditional) .............................................. 304Depth to the Centre of a Grid Block (Conditional) .................................................. 306Depth to the Tops of Grid Blocks (Conditional) ...................................................... 308Depths to Centre of Pay (Conditional) .......................................................................... 310Depths to Top of Block (Conditional) ...................................................................... 312Grid Tilt Angles (Conditional) ................................................................................. 314Corner Point Depths for Corner Point Grids (Conditional) ...................................... 316Lateral Corner Point Locations for Corner Point Grids (Conditional) ..................... 318Line-Based Corner Point Locations for Corner Point Grids (Conditional) .............. 320Complete Corner Point Locations for Corner Point Grids (Conditional) ................. 322Local Refined Grid (Optional) ................................................................................. 325Refined Grid Location (Conditional) ....................................................................... 337Dual Porosity (Optional) .......................................................................................... 339Dual Permeability (Optional) ................................................................................... 340Dual Porosity Subdomain Method (Optional) .......................................................... 341Assigning Fractional Volumes to Subdomain blocks (Optional) ............................. 343Subdomain to Subdomain Flow Transmissibility Multipliers (Optional) ................ 345Dual Porosity MINC Method (Optional) ................................................................. 347Shape Factor Calculation (Conditional) ................................................................... 348Matrix-Fracture Transfer Calculation (Conditional) ................................................ 350Allowing Addition Matrix-Fracture Connections (Optional) ................................... 352Fracture Spacing (Conditional) ................................................................................ 353Null Block Indicator (Optional) ............................................................................... 354Porosity (Required) .................................................................................................. 356Rock Compressibility (Required) ............................................................................. 357Pore Volume Modifiers (Optional) .......................................................................... 359Block Geometry Modifiers (Optional) ..................................................................... 361Permeabilities (Required) ......................................................................................... 368Netpay (Optional) ..................................................................................................... 370Netgross (Optional) .................................................................................................. 372

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Transmissibility Multipliers (Optional) .................................................................... 373Transmissibility Multipliers for Lower Indexed Block Faces (Optional) ................. 376Pinch Out Array (Optional) ........................................................................................... 378Pore Volume Cut-Off Threshold (Optional) ............................................................. 380Pinchout Tolerance (Optional) .................................................................................. 381Corner Point Tolerance (Optional) ................................................................................ 383Faults (Optional) ....................................................................................................... 384Aquifers (Optional) see Appendix G ........................................................................ 386Pressure Influence Function (Conditional) see Appendix G .................................... 393Sectors (Optional) ..................................................................................................... 395Sector Array (Optional) ............................................................................................ 397Sector Assignment via Names and an Array (Optional) ........................................... 398Flux Sector (Optional) .............................................................................................. 400Lease Planes (Optional) ............................................................................................ 402Irregular Connection (Optional) ............................................................................... 404Special Connections (Optional) ................................................................................ 407Fault Array (Optional) .............................................................................................. 409Compaction/Dilation Rock Type (Optional) ............................................................ 411Compaction/Dilation Rock Compressibility (Optional) ........................................... 413Compaction Rock Table (Optional) .......................................................................... 414Compaction Hysteresis Rock Table (Optional) ........................................................ 416Treat *CCPOR/*CROCKTAB/*CROCKTABH as Depletion Parameters/ Tables (Optional) ................................................................................................... 419Compaction Irreversibility Flag (Optional) .............................................................. 421Dilation Rock Table in Elastic Zone (Optional) ....................................................... 422Dilation Rock Table in the Plastic Zone (Optional) ................................................. 424Dilation Rock Table in Unloading Zone (Optional) ................................................. 426Dilation Rock Table in Recompacting Zone (Optional) ........................................... 429Dilation Rock Table in Reloading Zone (Optional) .................................................. 431Compaction/Dilation Rock Region (Optional) ......................................................... 439Dispersion Coefficients (Conditional) ...................................................................... 445Fault Transmissibilities (Optional) ........................................................................... 447

Component Properties 449Fluid Model (Required) ............................................................................................ 449Reservoir Temperature (Optional) ............................................................................ 453Oil and Gas PVT Table (Optional) ........................................................................... 454Oil and Gas Differential Liberation Table (Optional) .............................................. 459Gas PVT Table for API Model (Optional) ............................................................... 466Oil PVT Tables for API Model (Optional) ................................................................... 469Gas PVT Table for GASWATER Model (Optional) ................................................ 474Condensate - Oil and Gas PVT Table (Optional) ..................................................... 477Volatile - Oil and Gas PVT Table (Optional) ........................................................... 483

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Oil Compressibility as a Function of Pressure (Optional) ........................................ 489Bo Above the Bubble Point as a Function of Pressure (Optional) ........................... 492Oil Viscosity Above the Bubble Point as a Function of Pressure (Optional) ........... 494Bo above the Bubble Point as a Function of Pressure and STC Oil Density for API Tracking (Optional) ....................................................................................... 497Condensate Model - Undersaturated Eg, Bg, Zg Table ............................................ 502Condensate Model - Undersaturated Gas Viscosity Table ....................................... 506Oil Viscosity Above the Bubble Point as a Function of Pressure and STC Oil Density for API Tracking (Optional) .................................................................... 510Reference Pressure for Gas-Oil Capillary Pressure (Optional) ................................ 516Solvent PVT Table (Conditional) ............................................................................. 517Densities (Required) ................................................................................................. 521Under-Saturated Oil Compressibility (Optional) ..................................................... 524Oil Phase Viscosity Pressure Dependence (Optional) .............................................. 525Water Formation Volume Factor (Required) ........................................................... 526Water Phase Viscosity (Required) ................................................................................ 528PVT Type (Optional) ................................................................................................ 530Maximum Rate of Increase of Solution Gas Ratio or Bubble Point Pressure (Optional) .................................................................................................................... 531Maximum Rate of Increase of Oil Content or Dew Point Pressure (Optional) ........ 533Initial Gas-Oil Ratio (Conditional) ........................................................................... 535Gas and Solvent Mixing Parameter (Conditional) ................................................... 536Minimum Solvent Saturation (Conditional) ............................................................. 537Polymer Adsorption Table (Conditional) ................................................................. 539Polymer Viscosity Mixing (Conditional) ................................................................. 541Reference Polymer Viscosity (Conditional) ............................................................. 544Reference Polymer Concentration (Conditional) ..................................................... 545Polymer Permeability Table (Conditional) .............................................................. 546Reference Seawater Viscosity (Conditional) ............................................................ 547Gas Adsorption for Water Filled Blocks (Optional) ................................................ 548

Rock-Fluid Data 549Notes on Rock-Fluid Data ........................................................................................ 549Start of Rock-Fluid Property Input (Required) ........................................................ 552Relative Permeability Curves by Table (Required) .................................................. 553Water-Oil Relative Permeability Table (Conditional).............................................. 556Liquid-Gas Relative Permeability Table (Conditional) ............................................ 567Hysteresis Parameters (Optional) ............................................................................. 578Reduced Vertical Extent of Pcow Cycle for Trapped Oil Hysteresis (Conditional) ...... 583Method for Evaluating 3-Phase Kro (Optional) ....................................................... 584Rock Type (Optional) ............................................................................................... 587Saturation Endpoints for each Grid Block (Optional) .............................................. 588

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Maximum Relative Permeability/Capillary Pressure Values for Each Grid Block (Optional) .................................................................................................... 596Three Point Scaling Option (Optional) ..................................................................... 599Extrapolation of Krw outside of the *SWT table to 1.0 (Optional) .......................... 602Water Oil-Capillary Pressure (J Function) Shift for Each Grid Block (Optional) ........ 603Non-Darcy Flow in Reservoir (Optional) ................................................................. 604Non-Darcy Coefficient Correction Factor (Conditional) .......................................... 607Fracture Velocity Width Correction for PolymerWater Mixture Viscosity (Conditional) .......................................................................................................... 608Pressure Gradient Threshold Arrays ......................................................................... 609Leverett J Function Option ....................................................................................... 611J Function Surface Tension Arrays ........................................................................... 614Scale Deposition Table (Optional) ............................................................................ 615Scale Damage Table (Optional) ................................................................................ 617Subdomain Reinfiltration (Optional) ........................................................................ 618Adsorption Parameters for each Gridblock (Optional) ............................................. 620

Initial Conditions 623Notes on Initial Conditions ....................................................................................... 623Initial Conditions Identifier (Required) .................................................................... 626User Input or Vertical Equilibrium Selection (Required) ......................................... 627Initial Oil Phase Reservoir Pressure (Conditional) ................................................... 632Initial Bubble Point Pressure (Conditional) .............................................................. 633Initial Bubble Point Pressure vs. Depth (Conditional) .............................................. 634Initial Solution Gas Ratio vs. Depth (Conditional) ................................................... 636Initial Dew Point Pressure (Conditional) .................................................................. 638Initial Dew Point Pressure vs. Depth (Conditional) .................................................. 639Initial Oil Content (Rv) vs. Depth (Conditional) .......................................................... 641Initial Solvent Bubble Point Pressure (Conditional) ................................................. 643Initial Oil Saturation (Conditional) ........................................................................... 644Initial Water Saturation (Conditional) ...................................................................... 645Initial Polymer Concentration (Conditional) ............................................................ 646Initial Seawater Volume Fraction (Conditional) ....................................................... 647Initial Light Oil Volume Fraction (Conditional) ....................................................... 648Initial Light Oil API Volume Fraction vs. Depth (Conditional) ............................... 649Reference Depth and Reference Pressure (Conditional) ........................................... 651Depth to Water-Oil Contact (Conditional) ............................................................... 653Datum Depth Specification (Optional) ..................................................................... 656Specification of Capillary Pressure Values at Contacts (Optional) .......................... 659Specification of Method for Computing Oil Saturations in Gas Zone ...................... 662Specification of Water Saturation Above GOC or Below WOC (Optional) ............ 663Water Saturation Input Used with Gravity-Capillary Initialization (Conditional) ........ 665Non Equilibrium Water and Oil Saturation Used with Gravity-Capillary Equilibrium Initialization (Conditional) ................................................................ 667

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Numerical Methods Control 669Numerical Methods Control Identifier (Optional) ................................................... 669Maximum Timesteps (Optional) .............................................................................. 670Maximum CPU Seconds (Optional) ......................................................................... 671Maximum Timestep Size (Optional) ........................................................................ 672Minimum Timestep Size (Optional) ......................................................................... 673Normal Variation in Variables per Timestep (Optional) .......................................... 674Relaxation Options (Optional) ................................................................................. 676Adaptive Implicit Switching (Optional) ................................................................... 678Convergence of Newton's Method (Optional) .......................................................... 680Maximum Newtonian Cycles (Optional) ................................................................. 683Minimum Number of Newtonian Cycles (Optional) ................................................ 684Formulation Modification for Blocks with no Hydrocarbon .................................... 685Force Maximum Change Checks (Optional) ............................................................ 687Number of Cuts (Optional) ....................................................................................... 688Convergence Tolerance for Linear Solver (Optional) .............................................. 689Convergence Tolerance for Linear Solver (Optional) .............................................. 690Orthogonalization (Optional) ................................................................................... 691Solver Equation Ordering (Optional) ....................................................................... 692Solver Factorization Degree (Optional) ........................................................................ 693Pivot Stabilization (Optional) ................................................................................... 694Maximum Iterations (Optional) ................................................................................ 695AIMSOL/PARASOL Switch (Optional) .................................................................. 696Red-Black Ordering Check for Parasol (Optional) .................................................. 697Factorization Degree within PARASOL Classes (Optional) ................................... 698Factorization Degree between PARASOL Classes (Optional) ................................ 699Parasol Class Partitioning Pattern (Optional) ........................................................... 700Target number of Planes per Jacobian Domain (Optional) ...................................... 705Number of Threads to be Used (Optional) ............................................................... 706Complete Storage Grid Array of Jacobian Domain Numbers (Optional) ................ 707Target Number of Jacobian Domains (Optional) ..................................................... 708Target Number of Jacobian Domains based on Parasol Classes (Optional) ............ 710

Well and Recurrent Data 713Notes on Well and Recurrent Data ........................................................................... 713New Keywords and Options for the 2012.10 Release .............................................. 715New Keywords and Options for the 2011.10 Release .............................................. 716New Keywords and Options for the 2010.10 Release .............................................. 717New Keywords and Options for the 2009.10 Release .............................................. 719New Keywords and Options for the 2008.10 Release .............................................. 720New Keywords and Options for the 2007.10 Release .............................................. 721New Keywords and Options for the 2006.10 Release .............................................. 723New Keywords and Options for the 2005.10 Release .............................................. 725

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New Keywords and Options for the 2004.10 Release .............................................. 727New Keywords and Options for the 2003.10 Release .............................................. 728New Keywords and Options for the 2002.10 Release .............................................. 729New Keywords and Options for the 2001.10 Release .............................................. 731New Keywords and Options for the 2000.10 Release .............................................. 732New Keywords and Options for the 1999.10 Release .............................................. 733New Keywords and Options for the 98.05 Release .................................................. 734New Keywords and Options for the 98.00 Release .................................................. 735New Keywords and Options for the 97.00 Release .................................................. 737New Keywords and Options for the 96.10 Release .................................................. 740New Keywords and Options for the 96.00 Release .................................................. 741Old Options No Longer Supported by IMEX 97.00 ................................................. 742Well Management and Group Control ...................................................................... 743Specifying the Well and Group Control Hierarchy .................................................. 745Introducing Group Control after Start of Simulation ................................................ 747Data Incompatibilities Between 93.00 and Previous Versions of IMEX .................. 748Limitations of the Well Management and Group Control Module ........................... 749Recurrent Data from Other Sections ......................................................................... 750Well and Recurrent Data Identifier (Required)......................................................... 752Well Change Date (Conditional) .............................................................................. 753Well Change Time (Conditional) .............................................................................. 754Well Change First Time-Step Size (Optional) .......................................................... 755Maximum Time-Step Size (Optional) ...................................................................... 756Minimum Time-Step Size (Optional) ....................................................................... 757Setting Grid Blocks to Implicit or Explicit (Optional) ............................................. 758Setting Well Blocks and Neighbours to Implicit (Optional) ..................................... 760Set Frequency of Initialization of Bottom-Hole Pressure (Optional) ....................... 762Group Identification (Optional) ................................................................................ 765Well Identification (Required) .................................................................................. 770Well Backflow Model (Optional) ............................................................................. 773Well Head Method (Optional) .................................................................................. 775Well Head Iteration (Optional) ................................................................................. 778Simultaneous BHP and Well Head Iteration (Optional) ........................................... 780Perforations in Inactive Blocks (Optional) ............................................................... 782Well Type Definition (Required) .............................................................................. 784Shut in Wells above Formation (Optional) ............................................................... 787Well Status Definition (Optional) ............................................................................. 789Shut and Reopen a List of Wells (Optional) ............................................................. 791Tubing Data for Injectors (Conditional) ................................................................... 793Tubing Data for Producers (Conditional) ................................................................. 796Composition of Injected Water, Gas, and Oil Phases (Conditional)......................... 801Well Operating Constraints (Required) .................................................................... 803Maximum Number of Continue-Repeat (Optional) .................................................. 812

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Monitored Well Constraints (Optional) .................................................................... 813Alter Primary Well Operating Constraint Value (Optional) .................................... 821Alter Well Constraint Value (Optional) ................................................................... 824Sets/Alters a Wells Phase Productivity (Optional) ................................................. 828User-Specified Reference Depth for Well BHP (Optional) ..................................... 833User-Specified Pressure Gradient For Reference Depth for Well BHP (Optional) ....... 835Pressure Gradients for Calculation of Pressure Differences Between Completions (Conditional) .................................................................................... 837Alter Polymer Concentration (Optional) ...................................................................... 840Alter Seawater Injection Volume Fraction (Optional) ............................................. 842Well Scale Table Assignment (Optional) ................................................................. 844Layer Scale Table Assignment (Optional) ............................................................... 846Well Scale Removal (Optional)................................................................................ 848Layer Scale Removal (Optional) .............................................................................. 850Data for Workover Action for Wells (Optional) ...................................................... 851Resetting Well Operating Constraint after Value Change (Optional) ...................... 854Gas Lift Option (Optional) ....................................................................................... 856Gas Lift Control (Optional) ...................................................................................... 859Gas Lift Optimization (Optional) ............................................................................. 862Well Element Geometry (Conditional) .................................................................... 865Location of Well Completions (Conditional) ........................................................... 868Location of Vertical Well Completions (Conditional) ............................................. 878Location of Vertical Well Completions for Hybrid Refined Grids (Conditional) ........ 885Geometric Data for Deviated Well Completions (Conditional) ............................... 893Simplified Geometric Data for Deviated Well Completions (Conditional) ............. 898Data for Hydraulic Fracture Proxy (HFP) Model (Conditional) .............................. 901Special Relative Permeability Data for Well Completions (Conditional) ................ 906Group Production Constraints (Optional) ................................................................ 912Group Injection Constraints (Optional) .................................................................... 918Gas Make-up Target for Group Gas Recycling (Optional) ...................................... 929Maximum Make-up Gas Rate for Group Gas Recycling (Optional) ........................ 931Gas Producing Group for Group Recycling / Voidage Replacement (Optional) ........ 933Injection Group for Group Recycling/Voidage Replacement (Optional) ................. 935Maximum Re-injection Rate for Group Gas Recycling (Optional) ......................... 937Fuel Consumption Fraction for Group Gas Recycling (Optional) ........................... 939Maximum Fuel Consumption Rate for Group Gas Recycling (Optional) ................ 941Sales Rate Fraction for Group Gas Recycling (Optional) ........................................ 943Maximum Sales Rate for Group Gas Recycling (Optional) ..................................... 945Water Make-up Target for Group Water Recycling (Optional) ............................... 947Maximum Water Make-up Rate for Group Water Recycling (Optional) ................. 949Water Producing Group for Group Recycling (Optional) ........................................ 951Maximum Re-injection Rate for Group Water Recycling (Optional) ...................... 953Solvent Make-up Target for Group Solvent Recycling (Optional) .......................... 955

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Maximum Make-up Solvent Rate for Group Solvent Recycling (Optional) ............ 957Solvent Producing Group for Group Recycling (Optional) ...................................... 959Maximum Re-injection Rate for Group Solvent Recycling (Optional) .................... 961Monitored Group Constraints (Optional) .................................................................. 963Allow a Cycling Group to be Defined (Optional)..................................................... 967Allow Cycling Group Data to be Revised (Optional) ............................................... 978Allow Cycling Group Data to be Revised (Optional) ............................................... 980Select Cycling Group Cycle Part to Start and End Cycling Group Control (Optional) ............................................................................................................... 982Defining Group Production or Injection as Going Through a Manifold (Optional) ............................................................................................................... 984Pressure Constraint Translation for Manifolds (Optional) ....................................... 986Specification of Hydraulics Tables for Calculating Pressure Difference Between Manifold and Surface (Optional) .............................................................................. 988Manifold Depth for Calculating Pressure Difference Between Manifold and Surface (Optional) .................................................................................................. 990Group Artificial Lift Quantity Value (Optional)....................................................... 992Well Artificial Lift Quantity Value (Optional) ......................................................... 994Priority List for Automatic Drilling of Wells (Optional) .......................................... 995Group Apportionment Options (Optional) ................................................................ 997Apportionment Method for Meeting Group Targets (Optional) ............................... 999Priority Formulae for Apportionment (Conditional) .............................................. 1003Guide Rates for Groups or Wells ............................................................................ 1007Flag for Accompanying Groups or Wells under or not under Group pportionment (Optional) ...................................................................................... 1010Allows for a Set of Keywords to be Processed When a Specified Condition (Trigger) is Satisfied (Optional) ........................................................................... 1012Alter Well Constraint Value via a Multiplier (Optional) ........................................ 1033Group Production Constraints Multiplier (Optional) .............................................. 1037Group Injection Constraints Multipliers (Optional)................................................ 1040Define Reporting Group (Optional) ........................................................................ 1045Well/Group On-time Fraction (Optional) ............................................................... 1047Hydraulic Pressure Table (Conditional) ................................................................. 1051Set Number of Points for WHP Root Search (Optional) ........................................ 1059Control Layer Lumping Option (Optional) ............................................................. 1061Report Layer Lumping Option (Optional) .............................................................. 1067Control Layer Lumping Option (Optional) ............................................................. 1069Control Layer Lumping Option (Optional) ............................................................. 1070Control Layer Lumping Option (Optional) ............................................................. 1071Selection of Instanteneous Versus Actual Rates (Optional) ................................... 1072Dynamic Grid Amalgamation Control (Optional) .................................................. 1073Terminate Simulation (Required) ........................................................................... 1077

xii Contents User's Guide IMEX

Documentation, Templates and Execution 1079Introduction ............................................................................................................ 1079Documentation ....................................................................................................... 1079Templates ............................................................................................................... 1080Running IMEX ....................................................................................................... 1085

Sample Data Sets 1087Notes on Sample Data Sets .................................................................................... 1087MXSPE001.dat: First SPE Comparative Solution Model ..................................... 1091MXSPE002.dat: Three-Phase Coning Model ........................................................ 1094MXWWM004.dat WAG with Simple Wellbore Model ....................................... 1097MXWWM005.dat: Voidage Replacement & Lease Line Model .......................... 1104MXFRR002.dat: Dual Permeability Radial Coning Model .................................. 1107MXGRO008.dat: Hybrid Refined Grid Model ..................................................... 1111

Appendix A 1115Theoretical Outline ................................................................................................. 1115

Four Component Black-Oil Model with Dual Porosity ............................ 1115Dual Permeability ...................................................................................... 1119Subdomain Model ..................................................................................... 1120Matrix-Fracture Transfer Coefficient, sigma ............................................ 1120Independent and Dependent Variables ...................................................... 1121

Appendix B 1125Well Model ............................................................................................................. 1125

Total Mobility Weighted Injectors ............................................................ 1125Unweighted Injectors ................................................................................ 1125Well Injectivity .......................................................................................... 1125Producers ................................................................................................... 1126Wellhead Pressure Wellbore Model .......................................................... 1126

Appendix C 1129Calculation of Well Parameters .............................................................................. 1129

Appendix D 1133Figure D-1a: Numbering of the Grid (Non-Corner Point) .................................... 1133Figure D-1b: Numbering of the Grid (Corner Point) ............................................ 1134Figure D-2: Cylindrical Reservoir ......................................................................... 1135Figure D-3: Calculation of Gravity Components for a Tilted Grid System .......... 1136Figure D-4: Radial (Cylindrical) Coordinates ....................................................... 1137Figure D-5a: Depth Measurement ......................................................................... 1138

User's Guide IMEX Contents xiii

Figure D-5b: 3-Dimensional Variable Thickness Grid System (8x3x2) ............... 1139Figure D-6: Fault Throw Definition ...................................................................... 1140Figure D-7: Typical Data Curves ........................................................................... 1141Figure D-8: Typical Relative Permeability Curves ................................................ 1142

Appendix E 1143Polymer Option ....................................................................................................... 1143

Factors and Mechanisms Affecting Polymer Floods ................................. 1143Polymer Types ........................................................................................... 1149Mass Conservation Equations .................................................................... 1150Guidelines for Polymer Application .......................................................... 1151References for Polymer Option ................................................................. 1152

Pseudo-Miscible Option ......................................................................................... 1153Mass Conservation Equations .................................................................... 1153Pseudo-Miscible Considerations ................................................................ 1154References for Pseudo-Miscible Option .................................................... 1159

Appendix F 1161The Use of IMEX in Well Testing Applications .................................................... 1161

Appendix G 1169Analytical Aquifers ................................................................................................. 1169Mathematical Background ...................................................................................... 1170

Van-Everdingen and Hurst Method ........................................................... 1170Infinite Aquifer with Constant Rate Solution ............................................ 1170Limited Aquifers with Constant Rate Solution .......................................... 1171Carter-Tracy Method ................................................................................. 1171Fetkovich Method ...................................................................................... 1172

Practical Aspects of Using Analytical Aquifers ..................................................... 1173a) Selecting Type of Aquifer .................................................................... 1173b) Selecting Method of Solution ............................................................... 1173Aquifer Parameters .................................................................................... 1174

Model Defaults ....................................................................................................... 1175Appendix H 1183

Running IMEX Coupled to the GAP Surface Network Model............................... 1183Remote Simulation Job Submission via SSH ......................................................... 1195IMEX Results Accessible from RESOLVE Script ................................................. 1199Operation on Well Layers via RESOLVE Script.................................................... 1205

Keyword Index 1207

User's Guide IMEX Introduction 1

Introduction

Important Changes between IMEX 2012.10 and IMEX 2011.10 SIMULATOR CHANGES

Gas Adsorption The new keywords *ADGMAXV, *ADGCSTV, *ROCKDEN *ADGPCRIT (Rock-Fluid Section) and *ADS_WATERZONE (Component Properties section) allow the user to specify the Langmuir Isotherm parameters used to model the adsorption/desorption of gas to/from rock. This feature can be used to model simple adsorption effects in shale gas and CBM problems.

Multiple Solvent PVT Tables IMEX now optionally allows the PVTS table, the *OMEGASG keyword and the *DENSITY *SOLVENT keywords to be entered for each PVT region. This allows the solvent properties and mixing parameters between solvent and oil and solvent and gas to vary from PVT region to PVT region. This option is backwards compatible; no data modification is required for earlier solvent models to run.

Solver Technology Improved Cache Alignment For both fully implicit and adaptive implicit models this will improve parallel efficiency. Automatic Parallel Partitioning in 2 Dimensions (Any Two of the x, y, and z Directions) Two dimensional partitioning now can be set up automatically using *PPATTERN *AUTOP2D Improved Parallel Performance Improvements to the implementation of parallelization in IMEX have allowed the Simulator to run more efficiently on larger number of threads on Shared Memory Processors.

Improved Initialization of skewed corner point grids A very fine scale (optional) horizontal integration option has been introduced into the DEPTH_AVE integration option to be used with skewed corner point grids. Sub-keyword *FINE_INTG enables this option for corner point grids.

Additional *MOD Keyword Feature (*ARRAY) The *MOD *ARRAY option lets you replace values in a rectangular region of the grid, using an array of values. For example: *MOD *ARRAY value_array replaces the existing property values in the region by the corresponding values from value_array. The number of

2 Introduction User's Guide IMEX

values in value_array must be (i2-i1+1) (j2-j1+1) (k2-k1+1) and repeat counts are allowed. A value must be specified for each block in the I-J-K range, even if the block is null.

Other New Keywords Three Point Endpoint Scanning (*3PTSCALING) When *3PTSCALING is enabled an interior scaling point is added to the saturation endpoint scaling procedure. For each of Krw, Krow, Krg, and Krog, a different interior scaling point is used depending on the value of block water saturation (oil-water table) and block liquid saturation (gas-liquid table).

Krw Scaled between Swcrit and (1-Sorw), if block Sw is less than or equal to (1-Sorw), or between (1-Sorw) and (1-Soirw), if Sw is greater than (1-Sorw).

Krow Scaled between Swcon and Swcrit, if block Sw is less than or equal to Swcrit, or between Swcrit and (1-Sorw), if Sw is greater than Swcrit.

Krg Scaled between Slcon and Slrg, if block Sl is less than or equal to Slrg, or between Slrg and (1-Sgcrit), if Sl is greater than Slrg.

Krog Scaled between Slrg and (1-Sgcrit), if block Sl is less than or equal to (1-Sgcrit) or between (1-Sgcrit) and (1-Sgcon), if Sl is greater than (1-Sgcrit)

Extrapolate Krw from Krw (Sorw) to Krw=1.0 at Sw = 1.0 (*KRWEXTRAP) This keyword enables the linear extrapolation of water relative permeability from the last water saturation in the oil-water table to a saturation of 1.0 and a value of Krw of 1.0.

Enhancements to Existing Keywords *WATER_FIX Option 4 The WATER_FIX keyword has been used in the past to improve performance in water filled blocks when small amounts of oil or gas re-enter the block. Without this option, numerical issues could occur. The *WATER_FIX 4 option has been implemented to improve its performance. *WATER_FIX 4 is recommended for models where the complete disappearance of water leads to numerical issues. Water_fix 4 includes all of the enhancements included in water_fix 2 and 3.

Template Data Set Changes Added mxgro024.dat to demonstrate the *IRCONNECT keyword Added mxspr009.dat to demonstrate multiple solvent PVT regions Added mxsmo054.dat to demonstrate *PPARTITION *AUTOP2D (two dimensional partitioning) Added mxsmo055.dat to demonstrate a shale gas model using with desorption Added mxsmo056.dat to demonstrate a coal bed methane model using gas desorption Added mxsmo057.dat to demonstrate three point scaling (*3PTSCALING) Added mxsmo058.dat to demonstrate Krw extrapolation (*KRWEXTRAP) Added mxwwm054.dat to demonstrate on-time average layerlump rate output (*LAYERLUMP_ACTR)


Added mxwwm055.dat to demonstrate the specification of the minimum time interval between the opening of auto-drill wells in a dill queue (*DRILLT) *DRILLT not in 2012 manual, outboard documentation only

Data Incompatibilities with Previous Versions of IMEX Keywords *SECTOR, *SECTORARRAY and *SECTORNAMES may not be used together. The *LAYERXYZ calculation method has been improved, producing different results, in some cases, from the previous calculation method. Use of variable *PB and* PDW and *API initialization arrays may result in slightly different initialization. A problem, which occurred when inconsistent data was entered, has been corrected. This does not affect the *PBT, *PDWT or *APIT table vs. depth initialization options.

WELL MANAGEMENT CHANGES

*LAYERXYZ-METHOD *DIRECT The original method for calculating well bore radius and well permeability for directional wells has been improved. The New default method, directional weighting (*DIRECT) replaces the previous method (*OLD) which used cardinal weighting. Please see the keyword *LAYERXYZ-METHOD for a detailed description of the differences.

*MONITOR *SHUTLAYER1 Plug the most offending layer (which, when shut, causes the well to have the lowest/highest value of the monitored variable) and continue the simulation. *SHUTLAYER1 has the same effect as *SHUTLAYER for a rate type monitor (e.g. STO), but will be different for a ratio type monitor (e.g. GOR).

*MONITOR *AUTOLAYER1 Similar to *AUTOLAYER but corresponding to *SHUTLAYER1.

*GCONP *TARGET *NONE Remove any production target specified previously (including *VREP, *RECYCLE and *PMAINT). Existing maximum / minimum constraints are not affected.

*GCONI stream *TARGET *NONE Remove any previously specified injection target (including *VREF, *VREFP, *RECYCLE and *PMAINT) for the indicated stream (gas, water or solvent). Existing maximum constraints are not affected.

*LAYERLUMP_ACTR Use on-time averaged rates for calculation of rates and rate based quantities when using LAYERLUMPS. The default is to use instantaneous rates.

*DRILLT *DRILLT is a keyword to allow the specification of minimum time intervals between the auto-drilling of injectors and producers (keyword not in 2012 manual, outboard documentation only).


GRID CHANGES

*IRCONNECT Keyword A new irregular connection keyword (*IRCONNECT) has been added to the grid module. It is more flexible than the existing *SCONNECT keyword in that it is direction aware and so may be used with compaction and dilation models. It will use permeabilities in the blocks specified to be connected as well as input lengths, input interblock area and input connection direction to calculate block transmissibility.

*SECTOR, *SECTORARRAY and *SECTORNAMES Keywords *SECTOR, *SECTORARRAY and *SECTORNAMES may not be used together. In a single data set all sectors need to be defined using the same method. BUILDER can be used in the conversion of one format to another.

*MOD *ARRAY Input option Added The *MOD *ARRAY input option has been implemented for Grid Module variables (see Simulator Changes).

Corner Point Node Location Entry Specify the location and usage of each corner point node node of a fundamental grid. The keywords *NNODES, *NODEX, *NODEY, *NODEZ, *NODES, and *BLOCKS are used. This option reduces the size of the grid data and speeds up grid reading.

LGR Grid Definition Enhancement (Ratio Method) For a locally refined grid, the default action is to divide the parent block into child blocks of uniform size. To over-ride this default, use sub-keyword *RG to specify the ratios of child block sizes. This ratio method makes it easy to specify child block sizes when parent block size is odd or unknown.


Important Changes between IMEX 2011.10 and IMEX 2010.10 SIMULATOR CHANGES

Static Grid Amalgamation IMEX can now use the DYNAGRID Option to statically amalgamate, re-refine and de-refine grid blocks. The keywords *AMALGAMATE *INTO, *DEREFINE, *REREFINE and *DEAMALGAMATE are supported. Please see the *DYNAGRID Keyword in the Recurrent Data section for details

Solver Technology Improved Manual Parasol Partitioning The manual Parasol partitioning feature can be used to optimize Parasol partitioning when required, this feature, along with the Command Line Option info_partition allows the user to optimize parallel solver performance. Improved Parallel Performance Improvements to the implementation of parallelization in IMEX have allowed the Simulator to run more efficiently on larger number of threads on Shared Memory Processors.

Improved Crossflow Handling for API Tracking, Solvent and Polymer Models The fully mixed crossflow model previously had difficulties properly distributing fluids in the wellbore for API tracking, solvent, and polymer/seawater models. This issue has been addressed in the 2011.10 version of IMEX.

Improved API Tracking Formulation Prior to this release of IMEX, the API tracking formulation in IMEX could fail to converge adequately enough to ensure a consistent solution. This has been remedied in the 2011.10 release.

Improvements to Condensate Model STC Density Under some circumstances it was possible that the condensate STC density was not calculated properly, this has been corrected in the 2011.10 release. This was noted as an issue when the well module *VREFP voidage replacement option was introduced.

Other New Keywords Undersaturated Bo and Oil Viscosity with API Tracking (*BOTAPI, *VOTAPI) Prior to this release, the use of the *BOT and *VOT undersaturated tables was not supported when the API tracking option was used. Instead simpler options were required (see *APIGRAD and *CVO). This release introduces the *VOTAPI and *BOTAPI tables for API tracking models. The two tables are entirely analogous to the *BOT and *VOT tables for non API tracking models. Please see keywords *BOTAPI, *VOTAPI and *APIGRAD for more details. Limit Maximum Rate of Increase of Oil Content (*DRVDT) Analogous to *DRSDT for solution gas ratio, *DRVDT controls the rate of increase in condensate oil content with time. Please see the *DRVDT and *MINCYC keywords for more details.


STARS-Like Endpoint Scaling Option (*SCALING-STARS) On the face of it, IMEX and STARS endpoint scaling seem very similar; unfortunately the devil is in the details. Often it was necessary to use additional endpoint array keywords to ensure STARS and IMEX would use the same scaling. The differences were due to the fact that IMEX considered SLCON in the gas-liquid table to be the independent variable (changing SOIRG) when SWCON was altered on the oil-water relative permeability table and STARS considered that SOIRG was the independent variable (changing SLCON). In addition, STARS has the additional feature (which IMEX did not have) to allow the user to alter both critical and connate (or irreducible) endpoint pairs by altering one of the pair, when in a relative permeability table those endpoints are identical (i.e. critical = connate). Both of these differences have been addressed when using the *SCALING-STARS endpoint scaling option. Explicitly using the *SCALING-STARS keyword in any relative permeability table or defining the *SOIRG array keyword (standard IMEX uses the *SLCON array) will turn on *SCALING-STARS and enable IMEX to treat these two aspects of endpoint scaling as STARS does. Rs and Rv vs. Depth Tables Added (*RST and *RVT) Previous versions of IMEX allowed bubble point and dew point pressure versus depth tables to be entered in the initialization section. The new version of IMEX also allows the entry of Rs vs. Depth and Rv vs. Depth tables. These tables are converted into either Pb or Pdew vs. depth tables immediately after input. Please see keywords *RST and *RVT for a complete description. This option is incompatible with API tracking models. *FORCE_MAXCHK Keyword Normally the maximum change test (entered using the *MAXCHANGE keyword) is not applied on the first three Newton iterations of a timestep, and convergence is allowed even if the maximum change test is violated. When *FORCE_MAXCHK is active (*ON), convergence will not be allowed in the first three Newton iterations if the maximum change test is violated. However the test itself is not applied to repeat the timestep. If it is violated, the simulator will continue iterating until either the maximum change test is not violated within the first three Newton iterations or until the 4th Newton iteration is reached and the maximum change test is applied. The default for *FORCE_MAXCHK is *OFF for all models except the API tracking models, where the default is *ON. Please see the *FORCE_MAXCHK keyword for a complete description.

Enhancements to Existing Keywords *WATER_FIX Formulation Option Extended to Non Black Oil Models The WATER_FIX keyword has been used in the past to improve performance in water filled blocks when small amounts of oil or gas re-enter the block. Without this option, numerical issues could occur. The use of this option has been extended to the non Black Oil models, including API tracking, condensate and gas-water with condensate models. In addition, a new version of the keyword, *WATER_FIX 3, has been implemented to improve its performance.


*WATER_FIX 3 is recommended for API tracking models. Please see the *WATER_FIX keyword for more details. Capillary Pressure Stabilized Initial Water Saturation Input (*SWINIT) Compatible With the *DEPTH_AVE Initialization Option The useful *SWINIT option has been made compatible with the *DEPTH_AVE initialization option, previously it was only implemented for the *BLOCK_CENTER option. The *DEPTH_AVE implementation does not scale the oil water capillary pressure to maintain equilibrium; it adds the appropriate amount of capillary pressure to the block to maintain equilibrium. This is akin to the simulator determining the correct entry capillary pressure for each block based on the desired block saturation (*SWINIT). This has the benefit of allowing the option to function even if Pcow = 0.0 and usually results in capillary pressures which are less altered than by scaling (*BLOCK_CENTER). MINC-DK Option (*MINC and *TRANSD > 0) Similar to SD-DK (see *TRANSD), the MINC-DK option allows the use of the *MINC dual continua option with the *TRANSD keyword. When *MINC and *TRANSD > 0 are both input, in the vertical direction, all matrix blocks in a MINC block will be connected to the corresponding matrix MINC block directly above and below the current block. This allows the user to obtain the better areal transient response of MINC and have the same type of gravity drainage seen in dual permeability models. When this option is used, it is necessary to set all DKFRAC = 0.0 to avoid overestimating matrix-fracture and matrix-matrix flow within a MINC block. Please see keywords *TRANSD and *MINC for more details.

Template Data Set Changes Added mxdrm008.dat to demonstrate grid amalgamation Added mxdrm009.dat to demonstrate grid derefinement and rerefinement Added mxfrr021.dat to demonstrate MINC-DK Added mxsmo049.dat to demonstrate *DRVDT Keyword Added mxsmo050.dat to demonstrate the Use of *BOTAPI and *VOTAPI tables in an API tracking Model Added mxsmo051.dat to demonstrate the usage of *SWINIT with the *DEPTH_AVE initialization option and the *RST option (Rs vs. depth table) Added mxsmo052.dat to demonstrate the *SCALING-STARS option Added mxsmo053.dat to demonstrate the manual selection of Parasol partitions Added mxwwm053.dat to demonstrate the use of the logical OR condition in triggers

Data Incompatibilities with Previous Versions of IMEX *SCALING-OLD relative permeability endpoint scaling is no longer supported as it is incompatible with the *SCALING-STARS option


WELL MANAGEMENT CHANGES

*FRAC Added to *WELL Keyword Well fractions can now be defined per well and is useful for defining fractional (, , etc) wells when simulating elements of symmetry. Rates and well indices for full well are input, *FRAC determines the fraction of the rate and index to use. See the *WELL keyword for more information.

*AND and *OR Conditions in Triggers The trigger facility allows for conditional execution of certain user specified actions related to well and group control. Whereas previously only a single condition per trigger could be entered by the user, it is now possible for the user to specify multiple conditions for a single trigger. This essentially constitutes a compound logical statement with connecting logical operators AND/OR. The user also needs to assign a priority to each logical operator as this influences how the overall compound logical statement is evaluated. For more information refer to the explanation section of the *TRIGGER keyword in the well and recurrent data section of the user manual.

Voidage Replacement Injection Group The new keyword *VRI_GROUP is used to specify the injection group from which injection rates will be taken to calculate a production recycling or voidage replacement target for a given group or groups. Please see keyword *VRI_GROUP for more information.

Voidage Replacement by Pattern Capability A group named as a source for recycling or voidage replacement (in a keyword like *GPRODGROUP) can now be a reporting group. Since reporting groups allow for fractional well membership, use of a reporting group as a contributing or nominating group for recycling or voidage replacement enables imposition of injection targets based on a pattern type flood (using a reporting group which represents an element of symmetry). For example, the source group could be made up of the four producing wells surrounding an injector. The injection group defined using *VRI_GROUP may be a reporting group. This allows fractional well membership, allowing production targets based on pattern injection.

GRID CHANGES

Improve Corner-Point Efficiency These changes were made to the SR2 file format to improve efficiency and capacity for large corner-point grids. Results and IMEX can read both the new and previous SR2 file formats. Increase binary record index from 32 bits to 64 bits, effectively removing the limitation of number of blocks with *GRID *CORNERS (previously 22 million). *VAMOD and *VATYPE Keywords Added The *VAMOD and *VATYPE keywords were enabled in the grid module to more easily create elements of symmetry. This feature can be used in conjunction with *WELL *FRAC (see above).


*3DMF Added to SUBDOMAIN Option Normally when calculating the matrix-fracture transmissibility term for the subdomain dual continua model, the vertical flow into the subdomain is ignored. In certain circumstances this may significantly reduce the overall matrix-fracture transmissibility, the use of the option *3DMF introduces the M-F transmissibility terms from the vertical direction into the top and bottom subdomain cells. Please see the *SUBDOMAIN keyword in the Reservoir Description Section. *TRANSD Support Added to *MINC to Produce MINC-DK Option Support for simulator change.


Important Changes between IMEX 2010.10 and IMEX 2009.10 NOTES FOR IMEX 2010.10

Well Module 1. Completion Lumping Option 2. *WHYSTAB *AUTOWELL Monitor 3. *MXCNRPT Maximum number of Continue Repeats 4. *KRPERF *SORMAX Entry for Trapped Oil Hysteresis

Simulator 1. Improved Parallel Performance 2. Trapped Oil Hysteresis Option 3. IMEX-GAP Interface Improvements:

Handles Crossflow during shut in (like *MODELSHUT) 4. Flux Sector Reporting Option 5. Entry of Permeability and Non Darcy Correction Factor in Recurrent Data

Completion Lumping Option *LAYERCLUMP provides a way for the user to define a control lump - a set of layers (perforations, completions) which possesses a name and a set of computed rate, cumulative, and stream ratio values. To each control lump there is also an associated setting value. *LAYERRLUMP provides a way for the user to lump well layers in a group called a report lump. For report lumps, stream rates, cumulatives and production rate ratios are calculated and the user can design triggers based on these quantities. A given layer can be assigned a partial membership to report lump and the same layer can belong to more than one group. *RM-LAYERCLUMP removes membership of a layer from the named control lump. *RM-LAYERRLUMP removes membership of a layer from the named report lump. *CLUMPSETTING assigns a control setting or flow restriction parameter to the named control lumps. The flow restriction parameter is used as a multiplication factor in adjusting the value of the well index for all the layers belonging to a given control lump. There is also a set of computed rate, cumulative, and stream ratio values for each control lump. Triggers may be defined using these quantities specific to named control lumps; actions can be any valid well data lines, including lines which alter the control lump setting values. The syntax of the control lump based trigger statement is: *TRIGGER trigger_name *ON_CTRLLUMP control_lump_name quantity > value The syntax of the report lump based trigger statement is: *TRIGGER trigger_name *ON_RPTLUMP report_lump_name quantity > value See *LAYERCLUMP keyword for a list of quantities which can be used in control and report lump triggers.


*WHYSTAB *AUTOWELL Monitor *MONITOR WHYSTAB *AUTOWELL frequency can be used to monitor production well wellbore hydraulics stability using the *AUTOWELL option, which shuts the well for a specified time. *MXCNRPT Maximum Number of Continue Repeats Every well having *CONT *REPEAT (continue-repeat) specified through *OPERATE is entitled to one repeat of the current timestep if one of its operating constraints is violated. During convergence of a timestep, it is possible that different wells violate and then switch their operating constraints consecutively after each repeat. Although the maximum number of possible repeat cannot exceed the number of wells, it may lead to a significant increase of run time if there are many wells. Quantity nmxrpt limits the number of such repeats per timestep, and keyword *MXCNRPT lets the user override its default value (of 1). *KRPERF *SORMAX Entry for Trapped Oil Hysteresis SORMAX on the *KRPERF keyword allow the user to change this saturation endpoint in recurrent data. Sormax is the oil saturation in the two phase oil-water system at which oil first becomes immobile during the boundary/primary imbibition process (the imbibition starting from oil saturation equal to 1-Swcon). It only has an effect when the Krow hysteresis or trapped oil hysteresis is modeled for the rock type of the completion.

Improved Parallel Performance Improvements to the implementation of parallelization in IMEX have allowed the Simulator to run more efficiently on larger number of threads on Shared Memory Processors.

Trapped Oil Hysteresis Option Trapped oil hysteresis is now available for Pcow and Krow curves. To invoke the trapped oil hysteresis option, it is only necessary to define the imbibition Pcow in an SWT table using constant Pcow for water saturation values equal to and great than 1-Sormax. Once activated, trapped oil hysteresis couples Pcow and Krow hysteresis. Keyword *HYSKRO is not necessary and will be ignored. The endpoint array *SORMAX has been added to allow the user to enter values of Sormax on a block by block basis. The keyword *DAMP-PCOW-TROIL has been added to reduce the capillary pressure difference between imbibition and drainage curve which might result in a pressure oscillation. Please see the Tutorial section: The Trapped Oil Hysteresis Option for Pcow and Krow (Oil-Water System).

IMEX-GAP Interface Improvements IMEX-GAP Interface Improvements: Handles Crossflow during Shut in (like *MODELSHUT) When wells are shut in by GAP but experience crossflow during the shut in, the resulting pressure profiles around the well may change drastically if the productivity of well layers vary drastically and crossflow is occurring. This feature allows IMEX to shut in a GAP /RESOLVE controlled well using a *MODELSHUT type option, which allows crossflow in the shut in well. GAP/RESOLVE controls whether the well is *MODELSHUT or simply shut in. The user does not need to specify this IMEX keyword.


Flux Sector Reporting Option *FLUX_SECTORNAMES and *FLUX_ISECTOR keywords introduces special sector definitions which are used to calculate reservoir flow between these flux sectors. Flow into these sectors and between these sectors can be reported to the output print file and to the simulation results file as time series data. Flow can be further broken down into I-direction, J-direction and K-direction flow components. *FLUX_SECTORNAMES defines a list of flux sector names and their corresponding flux sector numbers. *FLUX_ISECTOR assigns these flux sector numbers to cells using standard array input options. Both keywords can only appear once in the data set. Please also see the *WPRN *SECTOR, *WSRF *SECTOR, *OUTPRN *FLUX_SECTOR, and *OUTSRF *FLUX_SECTOR keywords for output options. Entry of Permeability and Non Darcy Correction Factor in Recurrent data This option allows the input/redefinition of the permeability arrays *PERMI, *PERMJ and *PERMK and the non Darcy correction factor *NDARCYCOR in recurrent data.


Important Changes between IMEX 2009.10 and IMEX 2008.10 NOTES FOR IMEX 2009.10

Well Module 1. *ITUBE1/*PTUBE1 2. *GCONI Stream *PMAINT *PMMAXR d1 d2 3. *GCONPMULT *RECYCLE 4. *LAYERHFP 5. *PERFRG keyword removed

Simulator 1. Improved Parallel Performance 2. *DRSDT 3. Oil wet Initialization Option 4. *RTYPE Subkeyword of Relative Permeability Scaling Arrays 5. IMEX-GAP Interface Improvements:

Layer Information Available for Scripting Improved IPR Curve Generation

6. PTUBE1/*ITUBE1 Table Generation in Builder

*ITUBE1/*PTUBE1 PTUBE has been replaced by the more flexible PTUBE1, in addition ITUBE1 allows for the definition of injection tables using CMG standard well head pressure input table format. *PTUBE tables are still supported.

*GCONI Stream *PMAINT *PMMAXR d1 d2 Introduces the maximum surface rate of the specified injection stream that is available for the pressure maintenance. It is the summation of two sources: a fraction (d1) of the total produced (from the same group) and a make-up rate (d2). The values must be non-negative real numbers. The fraction d1 is nondimensional and defaulted to 0. The make-up rate d2 is (m3/day | bbl/day | cm3/min) for water and (m3/day | scf/day | cm3/min) for gas or solvent, and is defaulted to 1.0e+20. *GCONPMULT *RECYCLE This subkeyword specifies a recycling production target. This indicates that the production wells connected to this group produce such that the phase injected by the injection wells connected to this group as specified by *GAS, *WATER or *SOLVENT is reproduced (recycled) out of the reservoir.


*LAYERHFP *LAYERHFP allows the user to supply geometric and non Darcy information specifying productivity indices which act as proxies for vertical fractures (assuming pseudo radial flow) on a layer by layer basis.

*PERFRG keyword removed This keyword is no longer required as the *PERF keyword can be used instead.

Improved Parallel Performance Improvements to the implementation of parallelization in IMEX have allowed the Simulator to run more efficiently on larger number of Shared Memory Processors.

*DRSDT This option allows the input of the maximum rate of increase of solution gas ratio.

Oil Wet Initialization Option An oil wet reservoir when initialized using the depth average initialization option now produces realistic saturation profiles. This assumes that the reservoir was initially water wet and over time changed to an oil wet condition.

*RTYPE Subkeyword of Relative Permeability Scaling Arrays The relative permeability scaling arrays can now be made to operate on blocks which are members of specified rocktypes (RTYPES).

IMEX-GAP Interface Improvements The IMEX-GAP interface now is able to output well-layer level information to Resolve, this enables the user to script in Resolve using well-layer information. The IPR curve generation now optimally assigns pressure points in the IPR table to try to capture curvature more accurately.

*PTUBE1/*ITUBE1 Table Generation in Builder The new PTUBE1/ITUBE1 well head pressure tables are supported by the well head pressure calculator program. This now includes generation of injection tables as well as production tables which incorporate gas lift.


Important Changes Between IMEX 2008.10 and IMEX 2007.10 NOTES FOR IMEX 2008.10

Well Module 1. Cycling Groups 2. *GAPPOR *AUTODRILL stream identifier

Simulator 1. Improved Parallel performance 2. Improvements to the IMEX-GAP interface 3. NONDARCY GENERAL option 4. Fracture Cleanup Model

Cycling Groups Allow the user to specify data for EOR/IOR processes which rely on alternating production and/or injection cycles. Generally multiple cycles are required and each cycle consists of a number of well defined parts. Examples include water alternating gas injection (WAG) or cyclic st

imex user manual 2012

Documents

users guide

preface imex

components of cmg technology

cmg technology confidential

license management portion

reservoir simulation

reprise software

confidentiality agreement