M. Y Soliman, PhD, PE, NAI Ali Rezaei

Transcription

1 Role of Geomechanics in Production enhancement in Conventional and Unconventional Reservoirs M. Y. Soliman, PhD, PE, NAI and University of Houston UH Petroleum Engineering Department Energy Research Park 1

2 Our Department Highlights Established January professors 3 NAE 1 NAI 16 Adjunct professors 500+ undergraduate students 80+ MS students 29 PhD students Outline Introduction Early work Geomechanical considerations of multi-fractured wells Vertical wells Horizontal wells Conventional unconventional Issues and challenges Infill drilling Refracturing in horizontal wells 2

3 Introduction Rock mechanics considerations in fracturing well and stress shadow (interference) is not new. Application for multiple fracturing of horizontal and vertical wells is not exactly new Treatment issues exist in breakdown, propagation and re-orientation of fractures Conventional practices for stimulating horizontal wells must be challenged Analytical Solution, Semi-Infinite Fracture 1.2 CHANGE IN STRESS/NET EXTENSION PRESSURE _ _ 0 _ L/H Soliman, et al 2008 SPE

4 Analytical Solution, Penny-Shaped Fracture Dimensionless Stress Variation versus Dimensionless Distance Penny-Shaped Fracture 1.0 Stress Change / Net Extension Pressure _, _ Soliman, et al 2008 SPE Dimensionless Distance, L / H Refrac and multiple fracturing of vertical wells Proposed for low perm formation Declining fracture productivity Observed during drill cutting re-injection 4

5 Tangential Stress at wellbore Wall Tangential Stress No Fracture Tangential Stress after One Fracture Stress, psi Theta, degree Fracturing Seminar - M. Y. Soliman, PhD, PE - January 2010 Tangential Stress at Wellbore Wall Tangential Stress along the Wellbore Wall Tangential Stress, psi Sh=3000 psi rw=4.25 inch Pw=6000 psi Lf=6 inch Pf =2000 psi E=1,090,000 psi =0.225 Wang, et al SPE o W Frac, SH=Sh W/O Frac, SH=Sh W Frac, SH=1.5Sh W/O Frac, SH=1.5Sh W Frac, SH=2Sh W/O Frac, SH=2Sh W Frac, SH=3Sh W/O Frac, SH=3Sh 11 5

6 1 Min 1 Max 1 Min 2 Max 6

7 Pressure Distribution One-Frac Case Two-Frac Case Dual frac video Cumulative Production Cumulative production comparison for one and two fractures Total Production, mmcf Single Frac Two fracs Time, days 7

8 Planar Fracture Geometry PETR M. Y. Soliman, PhD, PE, NAI - Spring 2018 Non-Planar Fracture Geometry After Daneshy 8

9 Non-Planar Fracture Geometry V Single Fracture Single Fracture Single T-shaped Multiple Hmax Reorientation Multiple (at wellbore) Reorientation Hmin Abass - SPE Production & Facilities Journal, August 1996 Multiple Fracture (away from wellbore) Non-Planar Fracture Geometry After Warpinski 9

10 Fracturing Pressures from Arbitrarily Oriented Horizontal Wells North Sea Chalk Formation 7000 Fracture Initiation Pressure, psi Actual averaged well data (Less 370 psi perforation friction/tortuosity) Predicted fracturing pressure MFA- 16 MFA- 15 MFA- 14 MD-7 MFA- 13 MFB- 13 After Owens, et al SPE MFB- 15 MFA GeoMechanics Deviation Congress Angle, degrees April 18, 2018 pressure bpm Soliman, et al SPE

11 ISIP s for 12 consecutive Barnett Shale Hydra-jet Waterfracs placed in a single horizontal well in one day 12-Frac Hydra-jet Waterfrac 8060 Measured Depth, ft True Vertical Depth, ft Frac Targets ISIP's Instantaneous Shut-in Pressure, psi Soliman, et al SPE Change of Stress, Multiple Fracturing of a Horizontal Well Ratio of Change of Stress Contrast to Original Net Extension pressure During Multiple Fracturing of a Horizontal Well Ratio ofchange in Stress Contrast Fracture 5 Fracture 4 Fracture 3 Fracture 2 Soliman, et al 2008 SPE Soliman, et al 2008 SPE Dimensionless Distance between Fractures, L / h 11

12 Complexity Why it happens and how to maximize it? Brittle rock Low stress Contrast Naturally fractured Fracture parts of the formation that are Brittle, reduce stress contrast Zipper Frac Alternating Fracturing Modified Zipper Frac Different Designs of Fractures Alternating Fracturing 12

13 Geomechanical Considerations of Multi- Fractured Wells GeoMechanics Congress April 18, 2018 Consecutive Fracturing 13

14 Change in Stress, Single Fracture Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE Change in Stress, Single Fracture Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE

15 Change in Stress, Single Fracture Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE Change in Stress, Single Fracture Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE

16 Alternating Fracturing SPE Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE

17 Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE

18 Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE

19 Change in Stress, Alternating Fractures Change in Shear Stress( psi) Change in Minimum Horizontal Stress ( psi) Rafiee, et al 2012 SPE Modified Zipper Frac (MZF) 19

20 Change in Maximum Horizontal stress Rafiee, et al 2012 SPE Change in Maximum Horizontal stress Rafiee, et al 2012 SPE

21 Change in Maximum Horizontal stress Rafiee, et al 2012 SPE Implementing Alternating Fracturing (TTS) Alternating Fracturing Application by LUKOIL Eight horizontal wells in 2013/2014 in Western Siberia using TTS The horizontal wells post TTS-based MZHF have four times higher flow rate LUKOIL Group s Average Flow Rates in Western Siberia, bbl/d Horizontal wells post TTS-based MZHF Horizontal wells post standard MZHF Post-frac sidetracks 21

22 Propagation of Multiple Fractures (Clusters) Propagation of Clusters Rezaei, et al 2015 ARMA

23 Overlapping Zones of Two Interacting Fractures Rezaei, et al 2015 ARMA Fracture Interactions in Nature Microcrack in Glass A vein in granite Rock 25 a dike Overlapping spreading centers Swain 1978, Pollard 1984, Atkinson

24 Fully Poroelastic Model Infill well fracturing Refracturing GeoMechanics Congress April 18, 2018 Infill Well Drilling & Refracturing + q Several hours Depleted zones Parent Well + q 0 Dominated fractures + q Several years Dominated fractures Child Well Horizontal Well Horizontal Well Fractures at their final lengths Depleted area around fractures after production 24

25 Infill Well Fracturing Depletion of legacy wells creates a pressure sink that attracts fractures from new infill wells nearby The sink moves away from the legacy well with time It is desired to mitigate the asymmetric propagation in order to reach to the intact areas of the reservoir SPE MS Several methods to avoid asymmetric growth of the hydraulic fractures from infill well The asymmetry may be observed in both lateral and radial direction of the wellbore Study this issue numerically, SPE MS 25

26 Infill Drilling Effect of the Pore Pressure Depletion on Refarc Propagation Rezaei, et al

27 Propagation of the Child Fracture Vs. Spacing 6 months 1 year 5 years Rezaei, et al 2017 SPE Asymmetric Child Fracture Half-Length 6 months 5 years a b a b Rezaei, et al 2017 URTeC

28 Asymmetric Propagation Path from a child well 6 months 1 year Rezaei, et al 2017 SPE Safari, et al SPE

29 Fast Multipole Fully Poroelastic Model New numerical technique that has been used in quantum chemistry Method Run time, sec Exact PDDM 8802 FMPDDM - Chebyshev Polynomial degree FMPDDM - Chebyshev Polynomial degree GeoMechanics Congress April 18, 2018 Final remarks New challenges in stimulation of wells, specially in shale formations JPT listed some of those challenges that included Stress shadowing Fracture conductivity Optimization of fracture and fracturing parameters 29

30 THANK YOU 30