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Society of Petroleum Engineers Distinguished Lecturer Program www.spe.org/dl Completion of Hydrocarbon Bearing Shale Reservoirs
George Waters Schlumberger Society of Petroleum Engineers Distinguished Lecturer Program www.spe.org/dl 60,00060k MarcellusMarcellus Shale Shale Evolution of US Shales HaynesvilleHaynesville Shale Shale 50,00050k WoodfordWoodford Shale Shale FayettevilleFayetteville Shale Shale Initially driven by desportion s NewNew Albany Albany Shale Shale 40,00040k LewisLewis Shale Shale BarnettBarnett Shale Shale AntrimAntrim Shale Shale Focus shifts to pore gas OhioOhio Shale Shale 30,00030k
Deeper Gas Well Shale Producing 20,00020k
Higher Reservoir Pressures of Number
10,00010k Dramatic increase in production 00 ~1 BCF/day in 1997 197979 1981 198384 1985 1987 198989 1991 199394 1995 1997 199999 2001 200304 2005 200708 25002,500 +7 BCF/day in 2009 MarcellusMarcellus Shale Shale HaynesvilleHaynesville Shale Shale WoodfordWoodford Shale Shale 20002,000 FayettevilleFayetteville Shale Shale NewNew Albany Albany Shale Shale LewisLewis Shale Shale BarnettBarnett Shale Shale 15001,500 AntrimAntrim Shale Shale duction, Bcf duction, oo OhioOhi Shaleo Sha le
10001,000 Annual Shale Gas Gas Pr Shale Annual
500500
00 197979 1981 198384 1985 1987 198989 1991 199394 1995 1997 199999 2001 200304 2005 200708 Shale in Perspective: Permeability m. ate nn FF Sand h Lance nic Shale -D Carbo aa aa aa kk Jon Org Arab Salt Bric Bere
Unconventional
1000100 10 1.0 0.10.01 0.001 0.0001 0.00001 1e-06 md 100 nd = 0.0000001 D Shale Stimulation Requirements: Closelyyp Spaced Fractures
Extremely Low Matrix Permeabilities – Majority of Pressure Drop at Fracture Face – At Initial Reservoir Pressure 10s of feet from fracture for years – Hydraulic Fracture Complexity induces pressure drop from multiple points
Horizontal Wells Frequently Employed 10 Year Pressure Profile
– Drilled in direction of sh – Generate multiple, transverse hydraulic fractures 4500 Pressure Profile After 30 years 4000 with 30 Acre Well Spacing
3500
B1 : 1 1 B3 : 1 1
3000
2500 B2 : 1 1 B4 : 1 1
2000 Dense Fracture
1500 Patterns Required 1000 via
500 4500 Closely Spaced 4000 Vertical Wells
B6 : 1 1 3500 B3 : 1 1 B1 : 1 1 or B8 : 1 1 3000
B5 : 1 1 Horizontal Wells B4 : 1 1 2500
B2 : 1 1 B7 : 1 1
2000
1500
1000 Pressure Profile After 30 years with 15 Acre Well Spacing 500 Lateral Landing Example Best Petrophysics φ, k, GIP Mineralogy – Lowest Clay Volume Borehole Stability Breakout Expandable Clays Stress Lowest Closure Stress Oppgtimum Landing Points Frac Simulations to Quantify In-situ Stress Direction Induced Fractures, Borehole Breakout, Sonic Logs, & Microseismic
Induced Fractures
oriented in σH direction
Breakout oriented Microseismic events in σh direction orient in σH direction Calibration of In-Situ Stress Isotropic Stress Profile versus Anisotropic Stress Profile Isotropic Stress
Anisotropic Stress Barnett Shale Arkoma Shale Fracture Geometry Fracture Geometry
Natural Fractures normal to σH Natural Fractures Parallel to σH Low Horizontal Stress Anisotropy High Horizontal Stress Anisotropy Wide Hydraulic Fracture Networks Narrow Hydraulic Fracture Network
Vertical Well Lateral Azimuth = σH Spacing of Hydraulically Fractures
Example: bb Young’s Modulus = 3x106 psi Hy drau lic Width = 0. 05 in Spacing Stress Increase w = Δb (ft) (psi)
1 12,500 w=Δb 10 1,250 ε =w/b 25 500 50 250 Hooke’s Law 100 125 Δσ = Ε ε = Ε w/b Simultaneous Hydraulic Fracturing
“In-situ Pulverization” SPE 119635 Simultaneously Hydraulically Fracturing Results
1,000,000
100,000 [mscf]
Gas 10,000 [mscfd],
te aa R
1,000
100 0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0
Days
Initial Gas Simulfrac Gas Simul Cum Initial Cum The Role of Effective Stress – Do We Need Proppant? Force actinggy on fracture systems
σ’ = σ - αPf Barnett Shale Example 150000 5 MMPSI, 1.0 lb/ft2 D = 7,000 ft Pr = 0.55 psi/ft 5MMPSI05lb/ft25 MMPSI, 0.5 lb/ft2 5 MMPSI, 0.25 lb/ft2 σh = 0.60 psi/ft Pwf = 500 psi 120000 2 MMPSI, 1.0 lb/ft2 2 MMPSI, 0.5 lb/ft2 σH = 0.65 psi/ft 2 MMPSI, 0.25 lb/ft2 1 MMPSI, 1.0 lb/ft2 90000 Barnett 1 MMPSI, 0.5 lb/ft2 (md)
Initial Conditions During Production yy 1 MMPSI, 0.25 lb/ft2
σ’h = 350 psi σ’h = 3,700 psi 60000 σ’H = 700 psi σ’H = 4,050 psi Permeabilit Haynesville late Δσ’ = 350 psi Haynesville H-h Production 30000early Haynesville Shale Example Production
D = 11,000 ft Pr = 0.85 psi/ft 0 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 σh = 0.95 psi/ft Pwf = 7,,p500 psi Stress on Proppant σH = 1.00 psi/ft Pwf = 3,000 psi Initial Conditions During Production σ’h = 1,100 psi σ’h = 2,950 psi
σ’H = 1,650 psi σ’H = 3,500 psi
Δσ’H-h = 550 psi σ’h = 7,450 psi σ’H = 8,000 psi Fracturing Fluid Selection
Slickwater Crosslinked Gel Frac More Surface Area/Unit Cost Wider Fracture “Fairways” GlGels Fracture Initiation
Foams SPE 95568 Low Pore Pressure
Swelling Clays Slickwater Refrac Water Shortages Diversion FibBllSlSdFibers, Ball Sealers, Sand Slugs Simul-fracs, Zipper-fracs, Refracs
Propped Fractures SPE 95568 Effective Frac Conductivity Prop Volume, Viscous Fluids, Light Weight Props, Foams… Fracturing Fluid Additives Barite Salts Shale Compatibility Swelling Clays Scale Inhibitors 30.0
Mixed/Reused Waters 25.0 High TDS Waters 20.0 tio aa Surfactants 15.0
CST R 10.0
Impact Wetting Phase 5.0 Exacerbate Imbibition 000.0 01234567 Oil or Non-Wetting KCl [%] Bactericides Untreated Water Breakers Higgoyesh MW Polymers Iron Stabilizers Chlorite & Pyrite Perforation Practices – Impact on NWB Complexity σ Longer Perforation Clusters v 2 Can induce Parallel Fracturing σH 1.98 Q ρ Δp = perf 2 4 2 High Density Phasing c dp Np Tortuous Path leaving the Wellbore
Limited Entry Design σH Perf Clusters per Frac Stage
PfPerf Clust er Spaci ng Surface Can create Fracture Interference Wellhead
Perforation Performance Colinear Fracture Aligned Main Fracture HdHard RRkocks – Shor ter Pene tra tion along Wellbore Axis Secondary & Multiple Argillaceous Rocks – Collapsed Tunnels Competing Fractures Sand Jetting Perforations Deeper Penetration Physically Remove Rock Single Plane Phasing Colinear Frac Projection Projection of Main Fracture Projection of Secondary & Multiple Competing Fractures
Wellbore Projection Summary KtOtiiiShlGCltiKeys to Optimizing Shale Gas Completions:
– Identify Stimulation Drivers • Fracture Height Growth & Complexity • Fracture Conductivity & Fluid Compatibility – Must Perform “Science” At Beginning of Development • 3D Seismic Acquisition to understand Structure • Core Analysis for Mechanical Properties, Conductivity & Fluids Testing •Loggy Analysis to quantif y Petro pyphysics and Geomechanics • Microseismic Monitoring to Quantify Hydraulic Fracture Geometry – Evolves to Manufacturing Process • Maximize Drilling Efficiency • Optimize Well Spacing & Completion Process – Change Process as Acreage Changes – Continually Learn as Project Evolves Key Parameters for Shale Plays
Geology Engineering • Thermal maturity y Stress field and magnitude • Organic richness y Frac height growth • Mineralogy y Frac orientation • Matrix permeability Hydraulic vs. natural • Thickness y Frac complexity • Porosity y Frac conductivity • Fluid saturations y Fluid compatibility • Hydrocarbons in place • Faults and fractures • Adjacen t wa ter bibearing ftiformations Your Feedback is Important
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