Shale & Tight Reservoir Simulation Jim Erdle - VP/USA & LA OCTOBER 2012
AGENDA How CMG s simulators are being used o Shale/Tight reservoir modelling features o Shale/Tight reservoir modelling workflows How other simulators are being used Shale Operators using CMG s simulators SPE References
CMG S PRODUCTS IMEX Black Oil reservoir simulator GEM EOS-compositional reservoir simulator STARS Thermal/Reactive-Transport reservoir simulator GEOMECH Geomechanics simulator (GEM & STARS) BUILDER Model creation/editing GUI RESULTS Simulator output display GUI WINPROP PVT modelling CMOST SA, UA, Aided History-Matching & Optimization
MODELLING FEATURES PVT o Black Oil treatment (IMEX) primary production of dry gas, wet gas, black oil, volatile oil and gas condensate reservoir fluids o Multi-component EOS Treatment (GEM) Adds ability to model Multi-Component fluids including non-hc gases (e.g. CO2, H2S, acid gas, Flue Gas & N2) for EOR
MODELLING FEATURES Single vs Dual Porosity o Single Porosity if no open natural fractures o Dual Permeability if open natural fractures
MODELLING FEATURES Adsorped Components o Single gas component (new in IMEX for 2012) o Multiple gas or oil components (GEM)
MODELLING FEATURES Diffusion o Multi-component molecular diffusion (GEM) Competitive with darcy flow in some very low matrix perm situations Injection of solvents to aid liquid recovery (e.g. CO2, propane, etc.) Sequestration of CO2, acid gas, etc.
MODELLING FEATURES Relative Perm & Capillary Pressure o Independent curves for matrix, natural fractures & propped fractures Usually straight line for natural & propped fracs Matrix can be oil-wet or water-wet (which is it?) Can include hysteresis if modelling solvent injection Can also include wettability alteration via relative permeability interpolation (new in GEM for 2012)
MODELLING FEATURES Compaction/Dilation o Pressure-dependent Compaction/Dilation tables for modelling degradation of permeability & porosity In propped fractures, natural fractures & matrix, including hysteresis for modelling shut-in periods o Effective Stress-dependent Compaction/Dilation tables when using GEOMECH (GEM) Barton-Bandis approach for modelling of natural fracture perm vs Effective Stress
Conductivity Multiplier Conductivity Multiplier MODELLING FEATURES Compaction/Dilation Unpropped Fracture Compaction Table 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0 1000 1500 2000 2500 3000 3500 4000 Pressure (psi) Propped Fracture Compaction Table 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0 1000 1500 2000 2500 3000 3500 4000 Pressure (psi)
MODELLING FEATURES Initial Fluid Saturations o Non-equilibrium initialization of fluids for modelling presence and flowback of frac fluids in propped & natural fractures
MODELLING FEATURES Explicit Gridding of Propped Fractures o LS-LR-DK (TARTAN) grids to model propped fracs o Single Plane or Complex geometry o Non-Darcy flow in propped fracs
MODELLING FEATURES Explicit Gridding of Propped Fractures Single Plane geometry Complex geometry
MODELLING FEATURES Explicit Gridding of Propped Fractures o Automatic generation of TARTAN grids (BUILDER) o SRV delineation (BUILDER) Import & Filtering of Micro Seismic data Interactive selection on simulation grid display o TARTAN grids can be applied to any parent grid geometry Cartesian & Corner Point Grids
MODELLING FEATURES Explicit Gridding of Propped Fractures Hydraulic Fracture Wizard Microseismic Wizard
MODELLING FEATURES Time-dependent Propped Fractures o TARTAN grids can be added when wells are fracked Don t have to put all grids in place at beginning of run! Efficient way to model re-fracs & multi-well models o Compaction/Dilation Tables (with Hysteresis) can be time-dependent (coming in Dec 2012)
MODELLING WORKFLOW 1. Choose CMG simulator with required physics 2. Build single well base models 5. Build multi-well models 3. Perform SA & AHM on single well models 4. Forecast EUR for single well models 6. Perform OPT of multi-well models
Base Case Results Initial model with assumed values does not match historical production data o Too much gas produced o Not enough water produced
Sensitivity Analysis using CMOST Reservoir parameter uncertainty o Fracture Permeability o Fracture Width o Pressure Dependent Permeability of Fracture (CROCKTAB) o Langmuir Adsorption parameters o Diffusivity o Initial Water Saturation in Fractures (to model water from the HF fluid)
Sensitivity Analysis using CMOST
History Match Error Reduction Objective Function Error Reduced from 55% to 1.4% 21
History Match Final Results
History Match Final Results History match error reduction o Overall HM error reduced from 55% to 1.4% o Final Gas Rate Match error = 0.70% o Final Water Rate Match error = 2.13% Total Calendar Time to complete HM o Engineering Time = 10 hours o Computing Time = 15 hours (8 concurrent 2-way parallel jobs) o Total calendar time = 25 hours
-800-700 -600-500 -400-300 -200-100 0 100 200-900 -800-700 -600-500 -400-300 -200-100 0 200 ANOTHER APPROACH TO GRIDDING Representation of Single-Plane Propped Fractures o Some are using Logarithmically Refined grids over entire model in both X & Y directions (LS-GR-DK grids) to model single-plane fracs Porosity 2011-07-24 K layer: 1 Porosity 2011-07-24 K layer: 1 100 0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500 File: ECLIPSE_Global Grid Refinement.dat User: kpatel Date: 7/27/12 Scale: 1:2374 Y/X: 1.00:1 Axis Units: ft 200 100-100 0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500 File: CMG_Local Grid Refinement.dat User: kpatel Date: 7/27/12 Scale: 1:2480 Y/X: 1.00:1 Axis Units: ft 0 0-100 -100-200 -200-300 -300-400 Mangum -400 Mangum -500-500 -600-600 -700-700 -800 0.00 180.00 360.00 feet 0.00 55.00 110.00 meters -800 0.00 195.00 390.00 feet 0.00 60.00 120.00 meters -900 0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500-900 -100 0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500 Global Logarithmic Grids CMG s TARTAN Grids
ANOTHER APPROACH TO GRIDDING TARTAN grids = Same Results in 1/10 the time!
ANOTHER APPROACH TO GRIDDING TARTAN grids = Same Results in 1/10 the time!
Pressure -600-500 -400-300 -200 ANOTHER APPROACH TO GRIDDING TARTAN grids = Same Results in 1/10 the time! 6000 5000-200 Pressure (psi) 2039-11-24 K layer: 1 File: cmg_local grid refinement.irf User: kpatel 400 500 600 700 800 900 1,000 Date: 7/27/12 Scale: 1:1148 Y/X: 1.00:1 Axis Units: ft 4000 3000-300 Mangum -400 4,815 4,413 4,010 3,608 3,205 2000 2,803 2,401-500 1,998 1000 1,596-600 0.00 75.00 150.00 feet 0.00 25.00 50.00 meters 1,193 0 0 2000 4000 6000 8000 10000 12000 Time 400 500 600 700 800 900 1,000 791 Pressure 40 ft from propped frac is the same!
USING CMG FOR SHALE/TIGHT RESERVOIRS Anadarko Apache BG Group BHP Billiton BP Chesapeake Chevron Devon Encana EOG ExxonMobil Marathon Matador Noble Energy Reliance Rosetta Resources Samson Shell Statoil Talisman Total Venoco Vitruvian XTO
SPE REFERENCES CSUG/SPE 148710-PP Shale Gas Modeling Workflow: From Microseismic to Simulation A Horn River Case Study o Joint paper with CMG and NEXEN IPTC-14940 Evaluation in Data Rich Fayatteville Shale Gas Plays Integrating Physics-based Reservoir Simulations with Data Driven Approaches for Uncertainty Reduction o by Yitian Xiao et al (ExxonMobil) presented at 2012 IPTC Bangkok
SPE REFERENCES SPE 147596 Shale Oil Production Performance from a Stimulated Reservoir Volume o by A.S. Chaudhary, C. Economides & R. Wattenbarger (TAMU) presented at 2011 ATCE - Denver SPE 146975 Heat Transfer Applications for the Stimulated Reservoir Volume o by S. Thoram & C. Economides (TAMU) presented at 2011 ATCE - Denver
SPE REFERENCES SPE 132093 Accurate Simulation of Non-Darcy Flow in Stimulated Fractured Shale Gas Reservoirs o by B. Rubin (CMG) presented at 2010 WRM Anahiem
Thank you! Any Questions?