Wireline Mini-frac (Stress Testing)

Vinay K. Mishra, P. Eng.Reservoir Domain Champion NAOReservoir Domain Champion NAO

Schlumberger, Houston, Texas

6th International Symposium, Aug. 23-25, 2011

Applications of Mini-frac/Micro-frac/Stress Testing

Hydraulic Fracture Stimulation Fracture Confinement Critically Dependent Upon Stress Contrast Between Fracture Confinement Critically Dependent Upon Stress Contrast Between

Layers Fracture orientation

Cap rock integrity testCap rock integrity test SAGD Projects Underground gas storageg g g

Well Trajectory Design Input to Mechanical Earth ModelMud Weight Optimisation

Concept of Stress Testing

z

OverburdenStressObjectives:

F t O i t ti & Di ti

Max Hz Stress

Fracture Orientation & Direction Minimum In-situ stress

x

yMin Hz Stress Fracture

Solution:

Conventional CH Mini-Frac Operation.

Wireline OH Mini-Frac Operation. Logging derived Stress

Measurements.

Th f k f il ld b hi

Cap Rock Integrity

The consequences of a caprock failure could be catastrophic.

Fracture to Surface

Cap Rock P > m

Shear Failure Tensile Failure Reference: (Surface Steam Release of May 18, 2006 Joslyn Creek SAGD Thermal Operation, ERCB Staff Review and Analysis, February 11, 2010)

Sleeve Fracture prior to Mini-fracPacker Expands

Pumpout module

Wireline

Pressure gage P Downhole pump

Packer Expands

Packer

P

Inflate sealvalve

Interval sealvalve 1m

Software controlled in real time

Sleeve Fracture

P

valve 1m

Very stiff hydraulic system

C ti

Samplechamber

Continuous pressure records

chamber

A Wireline Conveyed Stress Tool

Pumpout module

Wireline

Pressure gage P Move tool to straddle

sleeve frac depth

Packer

g g

P

Inflate sealvalve

Interval sealvalve 1

p

Inflate packers

Packer

SlidingP

valve 1m

Injection between interval

gcoupling

Samplechamber

Fracture growth, closure reopening Hydraulic Fracture

chamber

Hydraulic Fracture Test ProcedureBreak Down, Growth, Closure, Reopen

PPressure

Minimum in-situ stress

Flow Time

Interval Pressure

FlowRate

Time

Wireline Mini-Frac Solution

Press Break-Down PressurePress PressureFrac Propagation Pressure

Re-Open Pressure

ISIP

Closure Pressure

FlowRate Time

Determination of Closure Pressure

Linear fit

Fracture closes

Fracture identification using Imaging Tools

Borehole imaging are useful tools for seeing fractures before mini-frac

Large vertical fractures may prevent packer seal

Small fractures assist or eliminate breakdown

I i t l d t l i di ti f

Before After

Imaging tools dont always see indications of mini frac

Case study 2

Wireline mini-frac in shaleObjective: Cap rock integrity test

Job details Sleeve frac performed 3 Leak off tests (LOT)

5 i j ti f ll ff 5 injection fall offs 2 flow back & BU

Interpreted Results Shale Formation mini-fracInterpreted Results Closure pressure determined Fracture initiation, fracture

growth pressure g p

Wireline Mini-frac Experiences Canada 2002-2011

> 120 SAGD Shale Cap Rocks

> 30 Gas Reservoir (Shale/siltstone)

> 5 fracture orientation

> 10 Oil Sands reservoir > 10 Oil Sands reservoir

Open Hole Gas Storage Shale Cap Rock

Cased Hole Gas Storage Shale Cap Rock

Conclusions

MDT Micro Frac provides Closure Pressure Closure Pressure

Far Field Stress Directions in conjunction with FMI Used as Calibration for Other Stress Measurements (sonic logs) It is a short interval measurement at a known depthIt is a short interval measurement at a known depth Mini-frac has been performed in Shale gas/cap rock / Sandstone / Carbonates reservoirs Job planning is important Job planning is important

References SPE 58086-PA, Title: Applications of Wireline Stress Measurements Authors Jean Desroches, A.L. Kurkjian, Schlumberger Oilfield

Services, Journal SPE Reservoir Evaluation & Engineering Volume Volume 2, Number 5 Date October 1999 SPE 25906-PA, Title: A New Wireline Tool for In-Situ Stress Measurements, Authors Thiercelin, M.J., Plumb, R.A., Desroches, Jean,

Schlumberger Cambridge Research; Bixenman, P.W., Jonas, J.K., Schlumberger Well Services; Davie, W.A.R., Schlumberger Evaluationand Production Services, Journal SPE Formation Evaluation Volume Volume 11, Number 1 Date March 1996

SPE 78486-MS, Title: An Advanced Method of Determining Insitu Reservoir Stresses: Wireline Conveyed Micro-Fracturing, Authors: A. Carnegie, Schlumberger; M. Thomas, M.S. Efnik, M. Hamawi, ADCO; M. Akbar, M. Burton, Schlumberger, International Petroleum Exhibition and Conference, 13-16 October 2002, Abu Dhabi, United Arab Emirates

SPE 127233-MS , Title: Advances in Wireline Conveyed In-situ Reservoir Stress Testing Measurements: Case Studies from the Sultanate of Oman Authors: Koksal Cig and Alyaqdhan Sulaiman Al Mandhari, Schlumberger, and Salem Mohammed El Msallati and Latifa Qobi,Petroleum Development Oman, Kuwait International Petroleum Conference and Exhibition, 14-16 December 2009, Kuwait City, Kuwait