Jose寫的水和二氧化碳驅(qū)氣PPT.ppt

1、Design and History Matching of Waterflood/Miscible CO2 Flood Model of a Mature Field: The Wellman Unit, West Texas,Chair of Advisory Committee: Dr. David Schechter Committee Members: Dr. Duane McVay and Dr. Luc Ikelle,by Jose Rojas Master of Science Candidate,Content,Research Objectives Review of Ge

2、ology Historical Reservoir Performance OOIP and Water Influx (Material Balance) Simulation Model Model Calibration History Matching Results: Primary Depletion Waterflooding CO2 Injection Conclusions and Recommendations,Objectives,Revise and integrate data from the reservoir description to develop a

3、full field, three-dimensional black oil simulation model to reproduce via history matching, the historical performance of the reservoir under primary, secondary and tertiary stages of depletion,Secondly, develop a calibrated model that can be used to evaluate, design and plan future reservoir manage

4、ment decisions.,Review Of Geology,Location,Terry county, TX, along the Horseshoe Atoll reef complex that developed in North Midland during Pennsylvanian and early Permian time,Review Of Geology,Field is considered geologically unique, because it comprises two types of reef construction,Built in deep

5、 clear water Large mound shape structure Strong depositional dip Water bearing,Built in shallow muddy(turbid) water Encroaching shales at the flank Smaller cone-shape structure Oil bearing,Wolfcamp deposited on top of the prominent Cisco Reef Curved layers at the bottom, more horizontal in upper str

6、ucture,Review Of Geology,Reef on Reef Depositional Model,Review Of Geology,Isopach Structure Map,Historical Reservoir Performance,Primary Depletion (1950 1979),Cum. Oil: 41.8 MMSTB RF: 34.6%,Historical Reservoir Performance,CO2 Injection (1983 1995),Historical Reservoir Performance,Chronological Sta

7、ges of Depletion,OOIP and Water Influx Material Balance,Estimate and validate previous OOIP assessments,Estimate water influx rate prior waterflooding,OOIP and Water Influx Material Balance,Hurst and Van Everdigen,Results,OOIP (N) aprox 125 MMSTB We10: approximately 8.0 MMRB,Final Aquifer Properties

8、,Simulation Model,Grid System,Use of flexible grids: corner point, non - orthogonal geometry.,K, direction subdivided in 23 layers based on porosity correlations (geological description),27 x 27 gridblocks I,J direction,Full field, 3-D black oil simulation “Imex” CMG,Total 16,767 gridblocks,Simulati

9、on Model,3D Structure Development,Simulation Model Input Data,Production data,Over 45 years of monthly cumulative oil, gas and water production from 47 wells was converted into daily rate schedules for simulation,Model initially constrained by oil rates and water/CO2 injection rates,Pressure data,Pr

10、essure measurements reveal good communication within the reservoir Use of BHP corrected and averaged to a common mid-perforation Static BHP seemed to be representative of the average reservoir pressure,Use of isopach maps resulted from geological and petrophysical study in 1994,Geological and strati

11、graphic correlation (Core vs Log data) Quantify major rock properties Lateral and areal continuity,Isopach Maps,60 geological contoured maps from gross thickness, porosity and NTGR were digitized Interpolation between contour allows model to be populated,Simulation Model Input Data,Permeability,Use

12、previous estimates from correlations between open-hole logs and core measurements,K = 10(0.167 * Core porosity 0.537),Water Saturation,Simulation Model Input Data,Simulation Model Input Data,Fluid Properties,Use PVT properties contained in previous lab and reservoir studies Bubble point: 1248 1300 p

13、sig Rs, 400-500 SCF/STB Oil Gravity, 43 API OFVF, 1.30 RB/STB Oil Viscosity, 0.4 cp Black oil fluid type,Relative Permeability,Special core analysis for core well No. 7-6 included measurements on only two samples with a low non-representative permeability,Use functions derived from Honarpours correl

14、ation (past studies),Simulation Model Input Data,Capillary Pressure Data,Only 4 samples, K 1 md (Special core analysis),Model Calibration History Matching,Objective: Validate the model adjusting the reservoir description until dynamic model match the historical production and pressures,Weight and ra

15、nk properties by level of uncertainty (quality, source, amount, availability of data),Historical Responses to be Matched,Fieldwide average reservoir pressure Fieldwide production rates Fieldwide GOR and Water cut Arrival times Individual responses (lesser degree),Results: Primary Depletion,No aquife

16、r modeled,Poor pressure response,First simulation runs,Need of external energy “recognized”,Results: Primary Depletion,Carter and Tracy “Analytic” MB case too strong (top) Aquifer size (,h), trans. (K,h) Reference datum adjusted Influx 20% greater, best case,Preliminary runs,Aquifer Calibration,Resu

17、lts: Primary Depletion,Preliminary runs,Water arrival time and cumulative did not match,Highest corresponds to MB,Poorest corresponds “no aquifer”,Poorest corresponds “no aquifer”,Best pressure match “sharp gas increase”,Results: Primary Depletion,Results: Primary Depletion,Diagnosis,Results: Primar

18、y Depletion,Final Results,Results: Primary Depletion,Final Results,Results: Waterflooding,4 producers converted to water injectors (1979),Injection below and above OWOC - 6,680 ft,Located at the flank forming a perimeter belt,Model primarily constrained by historical injection rate schedule,Injector

19、 Location,Results: Waterflooding,Initial runs,Fluid production needs to be controlled !,Diagnosis,Results: Waterflooding,Model Pressure Map,Model Calibration for Final Pressure Match,Results: Waterflooding,Results: Waterflooding,Model fluid match,Results: Waterflooding,WOC Movement,Results: CO2 Inje

20、ction,Miscible Displacement,Modification of the black oil sim.,Pseudo-miscible option with no chase gas,Based on the “Todd and Long- staff” theory,Highlights,Modifies physical properties and flow characteristics of the miscible fluids,Requires definition of new param.,CO2 PVT prop., MMP, o(P),Result

21、s: CO2 Injection,Initial runs,Abnormal increase in reservoir pressure,VRR greater than 1, correlates with sharp pressure increase VRR decreased (1992) correlating with decrease in pressure,What is happening ?,Results: CO2 Injection,Water Rate,Solvent Rate,Model is not able to reproduce rapid water r

22、ate increase (1986),In 1986, insufficient water and solvent production results in a dramatic increase in reservoir pressure,Initial runs,Most Uncertain Parameters influencing Production of Fluids,Model Calibration,Vertical Transmissibility Aquifer/reservoir vertical arrays local refinements Kv / Kh

23、1,Aquifer Properties , h,k,Relative Permeability Functions end points, shape, crit. Sat New set for middle reef Account for ESPs,Re-interpretation Completion intervals Plug-downs Include wells high on the struct.,“K.H” Term Prod / Inj Index,Uniform Mod. Fluid PVT,Local Absolute (K) Lesser degree,Res

24、ults: CO2 Injection,Negative Skin Stimulations - Acidizing,Diagnosis / adjustments,Results: CO2 Injection,Results: CO2 Injection,Good pressure match “primary”. Lost during waterflooding, poor at CO2 Inj.,Excess of H20 (waterflooding),Overall insufficient water and solvent production (tertiary), caus

25、ing over- pressurization.,Sensitivity runs,Results: CO2 Injection,Final match,Daily oil rate primary constraint expanded to daily total liquid rate (oil + water),Match is preserved (primary, H2O Inj.),Water and H2O breakthrough matched,Oil match sacrificed to match pressure,Results: CO2 Injection,Fi

26、nal match,Chronological Stages of Depletion,Results: CO2 Injection,Chronological Oil Saturation Distribution,a) Primary depletion,b) Waterflooding,c) CO2 miscible flooding Oil saturation considered overestimated due to the excess of oil production,Conclusions,Original fluids in place (according to s

27、imulation): Oil: 127.1 MMSTB Water: 139.0 MMSTB Gas: 54.3 BSCF Model OOIP, proved to be in close agreement not only with past estimations but also with the analytical solution of the material balance technique previously presented.,2. Cumulative water influx (8 MSTB) was estimated from application o

28、f the material balance theory and correlates quite well with water influx obtained in the “best case” being 8.5 MMSTB (first 10 years).,The natural aquifer greatly influenced production of fluids and consequentially, the predicted average reservoir pressure.,4. The initial set of aquifer parameters

29、was derived analytically by the Hurst and Van Everdigen theory and finally tuned by sensitivity analysis,5. The Carter and Tracy (analytic) method resulted as the best alternative to model the Cisco aquifer over the Fetkovich (analytic) and the numerical aquifer method.,Conclusions Cont.,The Cisco a

30、quifer provided energy and supplied water that encroached uniformly advancing the WOC 208 ft (prior to waterflooding) and an additional 210 feet (prior to CO2 injection) being in excellent agreement with field observations.,The use of a flexible grid system, honored the characteristic structure of t

31、he cone-shaped double anticline. The distorted grid blocks allowed a good representation of Wellman Unit geological features.,Historical water production and breakthrough times were identified as one of the most difficult parameters to match and one that greatly influenced the behavior of the predic

32、ted reservoir pressure response.,Conclusions Cont.,A complete pressure match was achieved through primary depletion, waterflooding and CO2 injection, however the match on liquid production was compromised in order to tune the final pressure match.,The results of this work provide the foundation for

33、future research into this hydraulically complicated reservoir,Recommendations for Future Work.,More research is recommended on the geology of the field with the aim of simplifying the total number of gridblocks, specifically the number of layers (23) by the use of some of the upscaling methods in th

34、e literature.,Consider the use of pseudo-functions during simplification of the existing model to increase the accuracy when modeling the production of fluids.,Place additional effort to update the current model by incorporating production and injection data from 1995 to the present time, thereby it can be use