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Joint Structural and Petrophysical History Matching of Stochastic Reservoir Models Thomas SCHAAF * & Bertrand COUREAUD Scaling up and modeling for transport and flow in porous media Conference Dubrovnik, 13-16 October 2008. Outline. Motivation : Getting reliable production forecasts
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Joint Structural and Petrophysical History Matchingof Stochastic Reservoir ModelsThomas SCHAAF* & Bertrand COUREAUDScaling up and modeling for transport and flow in porous media ConferenceDubrovnik, 13-16 October 2008
Outline • Motivation : Getting reliable production forecasts • Current methodology • Focus on the History Matching process • Proposed workflow to perform joint HM • Test case : Synthetic 3D waterflooding model • History Matching process & results • Conclusions & Perspectives
Motivation Decision taking in uncertain environment Getting reliable production forecasts
CPU intensive, non linear Numerical Modeling Steps Uncertain Input Parameters Outputs of interest Decision Making Objective Function Data Assimilation Under-determinded Problem Current Methodology 3 steps approach: • Sensitivity study with respect to the OF (ED+proxy model) • Multiple History Matching processes with remaining parameters • Propagation of uncertainties to forecasts using those HM models
History Matching Process • Updating simultaneously geological and simulation models • But structural and petrophysical uncertainties are seldom tackle at the same time; leading to sub optimal History Matched models All the ingredients are currently available to go ahead (Rivenæs & al.(2005) ; Suzuki & Caers(2008))
CONDOR (IFP R&D version) GEOMODELER Generic component : launch any exe file in the workflow Geomodeler workflow manager Proposed workflow (1/2) • Assisted History Matching (AHM) softwares are mature & versatile • Geomodeling softwares have powerful internal workflow managers • Geomodeling softwares can be launch in batch mode • Capitalize on existing geomodeling projects • Consider both structural and petrophysical HM
1 1 2 3 2 3 Proposed workflow (2/2) From a practical point of view : • Condor writes a text file with current inversion parameters value • Condor launches the geomodeler that : • reads that file • assigns the values to its own internal variables • launchs its internal workflow : • Structural modeling, • Facies modeling, poro/perm modeling, • Upscaling, export of the data file • Condor launches the fluid flow simulator • Condor get the simulation results, computes the OF value • Parameters updating • Next iteration • Capitalize on existing projects • Consider both structural and petrophysical HM
Synthetic 3D waterflooding model Geological Model : 5038100 Simulation Model : 201620 • 3 zones : • Top : Sequential Gaussian Simulation for poro/perm • Middle : Object based stochastic modeling • Bottom : SGS for poro/perm
Inversion Parameters set Fault throw Fault transmissivity Channels orientation Channels proportion kvkh ratio Mean k value for SGS Geological Model : 5038100 + Sorw = 7 parameters
Synthetic 3D waterflooding model Final oil saturation field Observation Data • 2 oil producers, 1 injector : 12 years of production history • Observation data : Fine scale fluid flow simulation results BHP & WCT
CONDOR GEOMODELER Condor inversion parameters have their counterpart in the geomodeler internal workflow Condor inversion parameters (Initial value, lower & upper bounds) History Matching Process • 7 parameters : Channels (%,dir), Fault (throw,T),kvkh, Sorw, Mean_kx
GEOMODELER WORFLOW MODELED GEOLOGICAL MODEL $throw = 15 m $Chan_dir = 90° History Matching Process • Concrete view of the Geomodeler workflow runs :
GEOMODELER WORFLOW MODELED GEOLOGICAL MODEL $throw = 25 m $Chan_dir = 110° Grid modified @ each iteration ! History Matching Process • Concrete view of the Geomodeler workflow runs :
Fault Throw Management • Freeze NW seismic horizons • Apply the throw to SE horizons
Initial OF value History Matching Results • Gradients based constrained optimization (not optimal, P. King work) • Numerical gradients computation (no adjoints …)
«Optimal» OF value History Matching Results • Gradients based constrained optimization • Numerical gradients computation
Conclusions & perspectives • Full History Matching Process : technicaly & operationnaly ok • Lead to more robust integrated geological stochastic reservoir models More reliable production forecasts • Ongoing work : • Better integration of the HM process in the global Geophysics / Geology / Reservoir Engineering Process eg. (fault throw / velocity model updates) Geologicaly realist updating of the reservoir structure ! • Parameterization/updating of the geological scale fields (facies,poro, perm) eg. gradual deformation, geomorphing techniques. • Prior sensitivity study should be done • Test gradients free algorithms : GA, simplex, PSO, VFSA, NEWUOA, hybrid or even better, Bayesian Approach!
Joint Structural and Petrophysical History Matchingof Stochastic Reservoir ModelsThomas SCHAAF* & Bertrand COUREAUDScaling up and modeling for transport and flow in porous media ConferenceDubrovnik, 13-16 October 2008
Outline • Motivation : Getting reliable production forecasts • Current methodology: • Sensitivity study • Multiple History Matching (HM) processes • Propagation of uncertainties to forecasts • Focus on the History Matching process : • Updating both geological and simulation models • Necessity to tackle both types of uncertainty : structural and petrophysical • Proposed workflow : • Versatile assisted HM softwares • Geomodeling software internal workflow manager • Test case : Synthetic 3D waterflooding model • History Matching process & results • Conclusions & Perspectives