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Value of Horizontal Shale Evaluation

DAN BULLER Global Advisor

Unconventional Optimization Formation & Reservoir Solutions

2 © 2011 HALLIBURTON. ALL RIGHTS RESERVED.

Defining the Sweet Spot – Vertical to Horizontal

Higher index of brittleness and low plasticity = highest fracture complexity & most surface area

Highest effective porosity (most free gas or oil)

Lowest amount of VTI mechanical anisotropy (horizontal clay layering) and highest amount HTI anisotropy (vertical fracturing)


Pseudo Brittleness from Rock Mechanics

SPE 115258

YM_BRIT = ((YMS_C-1)/(8-1))*100

PR_BRIT = ((PR_C-0.4)/(0.15-0.4))*100

BRIT = (YM_BRIT+PR_BRIT)/2


Pseudo Brittleness from PR & YM ShaleLog® Service – Haynesville Shale

Core “Calcite” facies. Lowest Clay

Slightly higher Pseudo Brittleness in upper = better horizontal target

Top

Bottom


Effective Porosity & 3-D Stress (VTI-HTI) Core Calibrated GEM Volumetrics & Oriented X-Y Dipole

Bossier Shale Haynesville CV Lime


SPE 115258

Shale Completion Strategy: Based on Formation Pseudo Brittleness

Brittleness Fluid System Fracture Geometry Fracture Width Closure Profile

70% Slick Water

60% Slick Water

50% Hybrid

40% Hybrid

30% X-Linked

20% X-Linked

10% X-Linked

Brittleness Proppant Concentration Fluid Volume Proppant Volume

70%

60%

50%

40%

30%

20%

10%

Liquid Production

Low

High

High

Low

Low

High

Youngs Modulus

7 E 6

6 E 6

5 E 6

4 E 6

3 E 6

2 E 6

1 E 6

Low

High

Barnett

Marcellus

Eagleford Haynesville

Barnett

Marcellus

Eagleford Haynesville


Reality Check – Current Horizontal Performance

Reason: Sweet spot targeted, but shales are rarely homogeneous over long horizontal course lengths and LWD GR steering doesn’t reflect complex reservoir behavior

Statistical Analysis of all available horizontal Production Log data in North America from equal spaced plug/perf stage frac’s supports: 61% of frac clusters produce less than the mean for any given well 41% of clusters produce less than a half of the mean (bottom quartile) for any given well 34% of clusters may have entry, but produce less than detectable resolution of the PL logs


– Real Time Steering – Min of 20’ Mudlogged Samples

collected at surface

– Thru bit/drill pipe conveyed logging

– Tractor, E-Coil, Pumpdown

– Tractor-While-Logging, E-Coil, Memory

Horizontal Evaluation Options

Geo Steering Open Hole – LWD Dipole & Imaging (Density,

Resistivity, GR, Acoustic) – LaserStrat

Open Hole Wireline

– OH Logging Suite – UltraSlim Logging

Cased Hole Evaluation

– RMT- Neutron Capture Spectroscopy & CHI Model

– Cased Hole Wave Sonic

Production Logs – CAT – SAT – RAT


Buller et al (2010) SPE 132990

VTI Anisotropy Viewed by Sonic Logs


Surveydegrees85 95

True Vertical Depthfeet 0150

Real-Time Gamma Rayapi0 150

Rate of Penetrationfeet per hr500 0

Real-Time AFR Image1 256

Top Right Bottom Left Top

1 16

8 7

6

5

4

3

2 15 14

13

12

11

10 9

Real-time Images for Wellbore Placement

Gamma Ray, Density and High Resolution Resistivity

GABI™

AFR™

ALD™


LaserStrat® – LIBS Chemostratigraphy Sample Cuttings Mechanical Properties


LaserStrat® Steering Application Target – Red & Green Upper Haynesville, Blue Lower Haynesville, 30% in zone


No frac issues encountered & hybrid gel design Brittleness index varying between 37-55

2010

Horizontal Cased Hole Shalelog Haynesville Core Area – Pulsed Neutron RMT Tool


Post Frac Production Log – day 45, well flowing 9MM

Brittleness Index vs. Gas Production


BP George A9H – 9 of 10 Water Fracs Placed – PL rate 8.2 MMCF/D


Frac Results Simplified

Near Wellbore Region (1-2 ft.) Higher injection pressure

Pad and proppant entry

High pressure drawndown during flowback

Higher Clay Interval Smaller effective

fracture width

Increased likelihood of screenout

Lower gas production higher embedment

Lower Clay Interval Wider effective fracture

width

Better chance of placing proppant and achieving complexity

Better gas production


Horizontal Evaluation Conclusions & Recommendations

Because of layered horizontal anisotropy effects, optimal evaluation should include horizontal open hole LWD dipole or cased hole cross dipole sonic for slow & fast shear detection. ALD density imager adds direct mechanical properties

Triple Combo & lithology inputs from either LWD suite or RMT Neural Net can be used for total clay volume and a horizontal anisotropy estimate by proxy

Laserstrat sample analysis is a viable mechanical proxy unless shale is too homogenous over horizontal, (assumes good hole cleaning)

Use formation evaluation for frac optimization. Plan frac stages by similar mechanical properties. Fewer entry points per stage appear reasonable in softer shales

Lateral placement rules dictate well performance. Frac’s placed in clay rich, or other layered, highly horizontal anisotropic rock, will underperform because of near well “chokes” and limited height growth


Thank you. Questions?

Market J., Quirein J., Pitcher J, Hinz D., Buller D., Al-Dammad C., Spain D., Odumosu T. 2010. Logging-While-Drilling in Unconventional Shales. Paper SPE 133685 presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September.

Buller D., Hughes, S., Market, J., Petre, E., Spain D., Odumosu T. 2010. Petrophysical Evaluation for Enhancing Hydralic Stimulation in Horizontal Shale Gas Wells. Paper SPE 132990 presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September.

Mullen M., Pitcher J., Hinz D., Everts M., Dunbar D., Carlstrom G., Brenize G. 2010 Does the Presence of Natural Fractures Have an Impact on Production? A Case Study from the Middle Bakken Dolomite, North Dakota. Paper SPE 135319 presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September.

J.Market, C.Bilby, and G.Varsamis, 2011, Introducing the First LWD Crossed-Dipole Sonic Imaging Service prepared for presentation at the SPWLA 52nd Annual Logging Symposium held in Colorado Springs, Co, USA, May 14-18, 2011.

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