static model development
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- Kunal RathodFinal year petroleum engineering student of
School of Petroleum Technology, RaisanYear : 2012-13
Static Model Development
Section 3
Section 4
Section 2
Section 5
Static model development |
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Section 1
This presentation is a part of our B.Tech project “A comprehensive
study of effect of well spacing on ultimate recovery”.
Section 3
Section 4
Section 2
Section 5
Static model development |
Introduction to static reservoir modeling
For decision making and improving the estimation of reserves; a computer model of a reservoir is constructed which we call as “The Reservoir Model”.
Section 1
Real Model Computer Model ……How ??
CLICK HERE FOR MORE INFO
Building the model
So this is how it may be done…!!?
Introduction to static reservoir modeling
Geocellular modelingIt is a way to describe the subsurface in 3D space (mathematically), which is constrained by a structural and stratigraphic framework.In a layman’s language, it is the process of generating the model/prototype of the subsurface. This model will resemble the real reservoir model. The physical properties of the reservoir are stored at the grid points or at the centers of gravity (3D voxels).
So the first thing is to define the GRID
Grid The simulation grid is the definition of how we divide, or discretize, space in order to solve the differential equations numerically. Common grid co-ordinate system includes Cartesian Cylindrical Corner Point Curvilinear
Introduction to static reservoir modeling
Grid Simulation |
Selection of proper GRIDIt is necessary that the grid that is defined should have desired level of accuracy in the solution of the flow equations; properly represents the reservoir geology; locations of wells, boundaries, faults, etc. and has the lowest computer memory and time requirements to solve the problem.
Common rules of constructing GRID In case of cylindrical grid system, the grid spacing is at logarithmic scale difference. The grid spacing should be such that the adjacent block size should not increase by the factor more that 3. Even the pressure drop between the blocks should not decrease by 30-20 %. Reservoir flow units should be separated by grid block boundaries. Vertical discretization should be fine enough for accurate accounting of gas percolation and migration and/or gravity over-ride or under-ride
Grid Simulation | using CMG simulator (version 2007.1)
GRID type (Cartesian, corner or cylindrical)
# of grid blocks in x, y and z direction respectively
Here, 10 is width of the block and 3 is the # of blocks in
each direction
Grid Simulation | using CMG simulator (version 2007.1)
A block with width 10m each
in x, y & z direction
Date @ which simulation starts
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Section 4
Section 2
Section 5
Static model development |
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Once the GRID is defined properly all we need to do is to give “LIFE” to our model …
Which can be done in 4 stages :
Structural Modeling
Stratigraphic Modeling
Lithological Modeling
Petrophysical Modeling
Section 1
Section 3
Section 4
Section 5
Static model development |
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Section 1
Identifying the Structural top &
Interpreting the set of faults
Section 2
Structural modeling
Identifying structural topStructural top identification means recognizing the geometric structure of hydrocarbon trap. The workflow(in petrel) for the same would be :
Load SEG-Y format data.
Interpret it manually.
Full range of tools allows us to take a traditional line-by-line approach combined with the latest algorithms and tools including amplitude & waveform based tracking for best interpretation, allowing us to achieve rapid results
Structural Modeling |Using Petrel 2009 Seismic Simulator
Interpreting set of faultsSince the presence of fault/set of faults directly makes a huge difference to the field development plan and production characteristics…we need to carefully investigate it’s presence.Fault can be interpreted in the same way (as we seen the workflow in case of structural top).
But consider only Sealing faults !!!
BUT STILL …THERE CAN BE NUMEROUS FAULTS
SO, MANUAL INTERPRETATION BECOMES TEDIOUS !
Structural Modeling |Using Petrel 2009 Seismic Simulator
Structural Modeling |Using Petrel 2009 Seismic Simulator
So many faults
Can we do it automatically ?
??..
Structural Modeling |Using Petrel 2009 Seismic Simulator
The Petrel Automated Structural Interpretation module uses an advanced computing algorithm "AntTracking" to overcome the tedious task.
Benefits :
Increases structural accuracy and detail & thus provides unbiased, repeatable & highly detailed mapping of discontinuities.
Significantly reduces tedious manual interpretation time.
All u need is ANT TRACKING module
The Ant Tracking workflow consists of four independent steps:
Structural Modeling |Using Petrel 2009 Seismic Simulator
Step 1
Enhance the spatial discontinuities in your seismic data using any edge detection algorithm (i.e. variance, chaos, edge detection) and optionally, pre-condition your seismic data by reducing noise.
Step 2 Generate the Ant Track Cube and extract the fault patches.
Step 3 Validate and edit the fault patches.
Step 4 Create final fault interpretation model.
Section 2
Section 4
Section 5
Static model development |
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Section 1
Well-to-Well correlation :
The basic data used for well-to-well correlations are the
logs recorded in open hole or cased hole, and cores.
Section 3
Stratigraphic modeling
Analytically the best technique to establish the correlation between the geological units is by using the sequence stratigraphic method.
As per this technique the deposition of sedimentary bodies is governed by the combined effects of changes in sea-level, sedimentation, subsidence and tectonics.
On this basis, we can identify sequences of different hierarchical order within a geological unit that are separated by sequence boundaries which represent Unconformities or maximum flooding surfaces.
Stratigraphic Modeling |Analytical approach
Stratigraphic Modeling |Analytical approach
Biostratigraphy
Production data (density, GOR etc.)
Stratigraphic Modeling |Analytical approach
Drilling Data (ROP)
Formation & Pore pressure
In Petrel we can display and organize your logs in a flexible 2D visualization environment.
Stratigraphic Modeling |Petrel v2009 Simulator
A flexible 2D canvas allows simultaneous display of logs, seismic, 3D grid, and simulation results.
Stratigraphic Modeling |Petrel v2009 Simulator
Stratigraphic Modeling | Petrel v2009 Simulator
The workflow for correlation can be given as follows :
[1] Import well log las-file data :By importing well trajectories, well deviations and logs(las file) you can pick/select any horizon top and analysis it.
[2] Create cross sections :Under “window” option select “new well section window”. Then you can select the #of wells (to display their cross section)
Then after you can carry out other secondary operations (colorfill, thickness etc.)
Stratigraphic Modeling | Petrel v2009 Simulator
[3] Revise formation top picks & compare: Pick horizon tops in the well panel and see the effects directly in 3D, or vice versa.Now you can compare the required section of the well log to other sections by using “ghost curve” option in the right hand side bar of petrel.Using ghost curve you can clip out a small section of your seismic and drag it over to other parts to correlate acrossfaults. (refer to next slide)
Stratigraphic Modeling | Petrel v2009 Simulator
Now after selecting the portion, you can drag it to the other portion of the log to figure out the similarity between them.(see the yellow curves in box)This operation is called ghosting.
[4] Evaluate real-time updated picks in 2D and 3D interpretation windows :You can view the real time updated picks by turning ON (simply click on it) the well section fence.
Section 2
Section 3
Section 5
Static model development |
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Section 1
Identifying and recovering hydrocarbons requires an
accurate, high-resolution geological model of the reservoir
structure and stratigraphy.
Sedimentological Model Classification of facies
3D distribution of facies
Section 4
Lithological modeling
As a rule, facies Modeling can be performed using appropriate deterministic or stochastic functions which allow us to generate 2 or 3 dimensional spatial distributions of significant characteristics, such as porosity and permeability, directly from well data.
The idea behind this procedure is that the petrophysical characteristics of the reservoir can be considered intimately linked to the lithological facies.
In practical terms, the lithological model of a reservoir is constructed by integrating an ideal representation of the reservoir (sedimentological model), a classification stage (definition of facies) and a spatial distribution stage (three-dimensional model).
Lithological Modeling |
Lithological Modeling
3D distribution of facies
Sedimentological Model
Classification of facies
Lithological Modeling |
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Lithological Modeling |
.Example of a stochastic model of
facies
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Section 4
Section 3
Static model development |
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Section 1
Deterministic Model
Stochastic Model
Section 5
Petrophysical modeling
The values between the cells are interpolated by various techniques. Two of the important techniques are:
• Deterministic Model• Stochastic Model
Deterministic Model
It uses moving average method, based on inverse distance weighting.• Open the petrophysical process option from the menu.(this will open a dialog box)• From the dialog box, select Use Existing Property and select the Porosity property as the property to be modeled from the drop down menu.
Petrophysical Modeling |using Petrel v2004
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.• Select the Moving average as the Method; leave all other settings as default.• Click on OK; display the model in 3D window and it would appear like :
Stochastic ModelThis method uses Sequential Gaussian Simulation method. To create stochastic Modeling follow the given steps:
• Open the Petrophysical Modeling process. Go to the Use Existing property and select Porosity from the drop-down list.• Activate the required zone by clicking on the zone tab.• Select Sequential Gaussian Simulation as the method to use.• In variogram tab, select the Variogram type. In it select the Major Range, Minor Range, Vertical Range and Azimuth. Then after click on OK and create the property model.
Petrophysical Modeling |using Petrel v2004
. .Stochastic method : user defined variogram and range.
Journal article, organization as author :ESSCA Group, L'ESSCA, la Grande Ecole directement Petrel 2009 Seismic to Simulation Software, 2009.Petrel-A Schlumberger product group, Release notes; Petrel™ Workflow Tools 2004, November 2004.
Encyclopaedia on the Internet : Portale Treccani. L'enciclopedia Italiana; Oil Field Characteristics and Relevant Studies [Internet] , Italy Inc.; 2008, Available from : http://www.treccani.it/enciclopedia/oil-field-characteristics-and-relevant-studies_(altro)/
Part of an Internet website :West Virginia University, Department of Geology and Geography [Homepage on Internet], West Virginia : The University; c2008, Available from : http://www.geo.wvu.edu/~wilson/casi/
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