2 petroleum reservoir engineering slides (feb 2016)

GEOPET BACHELOR PROGRAM IN PETROLEUM ENGINEERING PETROLEUM RESERVOIR ENGINEERING 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Learning Objectives At the end of this lecture, you should be able to understand the fundamentals of reservoir engineering and some basic analyses/calculations as follows:  PVT Analysis  Special Core Analysis  Well Test Analysis  Production Forecast 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT References L.P.Dake (1978) Fundamentals of Reservoir Engineering, Elsevier Science, Amsterdam L.P.Dake (1994) The Practice of Reservoir Engineering, Elsevier Science, Amsterdam B.C.Craft & M.Hawkins (1991) Applied Petroleum Reservoir Engineering,Prentice Hall, New Jersey T Ahmed (2006) Reservoir Engineering Handbook , Gulf Professional Publishing, Oxford 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Outline  Key Concepts in Reservoir Engineering  Fundamentals of Oil & Gas Reservoirs  Quantitative Methods in Reservoir Characterization and Evaluation 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Part I Key Concepts in Reservoir Engineering 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Definition of Reservoir In petroleum industry, reservoir fluids is a mixture of hydrocarbons (oil and/or gas), water and other non-hydrocarbon compounds (such as H2S, CO2, N2, ) 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Definition of Engineering Engineering is the discipline or profession of applying necessary knowledge and utilizing physical resources in order to design and implement systems and processes that realize a desired objective and meet specified criteria 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Definition of Engineering Engineering is the discipline and profession of applying necessary knowledge and utilizing physical resources in order to design and implement systems and processes that realize a desired objective and meet specified criteria 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Necessary Knowledge  Knowledge about oil & gas reservoirs  Reservoir Rock Properties & Behavior during the Production Process  Reservoir Fluid Properties & Behavior during the Production Process  Fluid Flows in Reservoirs 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT Necessary Knowledge (cont’d)  Technical & Scientific Knowledge  Quantitative Methods for Reservoir Characterization  Quantitative Methods for Reservoir Evaluation 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 10 Tracy’s method  Step 6: calculate cumulative oil production Np 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 234 Tracy’s method  Step 7: calculate the oil and gas saturations at selected average reservoir pressure  Step 8: Obtain the relative permeability ratio krg/kro at Sg  Step 9: Calculate the instantaneous GOR 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 235 Tracy’s method  Step 10: Compare the estimated GOR in step with the calculated GOR in step  If the value are within the acceptable tolerance, proceed to step 11  If not, set the estimated GOR equal to the calculated GOR and repeat the calculations from step  Step 11: calculate the cumulative gas production 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 236 Tracy’s method  Step 12: results of the calculations are based on STB of oil initially in place, a final check on the accuracy of the prediction should be made on the MBE or  Step 13: repeat from step 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 237 Exercise 13  The following PVT data characterize a solutiongas-drive reservoir:  Pi = Pb = 4350 psi; Sw = 30%; N = 15 mmSTB  Predict the cumulative oil and gas production to 3350 psi 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 238 Coupled method for production forecast Principles:  IPR: flow performance from the reservoir  TPR: flow performance from the wellbore 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 239 Coupled method for production forecast Oil production forecast through periods:  Transient flow period  Pseudo–steady single-phase flow period  Pseudo–steady two-phase flow period 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 240 Oil production forecast for transient flow period IPR: TPR: based on models of Poettmann–Carpenter and the modified Hagedorn–Brown 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 241 Oil production forecast for Pseudo– steady single-phase flow period IPR: TPR: based on models of Poettmann–Carpenter and the modified Hagedorn–Brown 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 242 Oil production forecast for Pseudo– steady two-phase flow period IPR: Vogel’s correlation TPR: The Hagedorn– Brown correlation 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 243 Oil Production Forecast for SolutionGas Drive Reservoirs The commonly used material balance model is found in Craft and Hawkins (1991) The following procedure is taken to carry out a production forecast during the two-phase flow period: • Step 1: Assume a series of average-reservoir pressure pavg values between the bubble-point pressure pb and abandonment reservoir pressure pa 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 244 Oil Production Forecast for SolutionGas Drive Reservoirs ▪ Step 2: Estimate fluid properties at each average-reservoir pressure, and calculate incremental cumulative production Np and cumulative production Np within each average-reservoir pressure interval ▪ Step 3: Perform Nodal analyses to estimate production rate q at each average-reservoir pressure ▪ Step 4: Calculate production time t for each average reservoir pressure interval by t =  Np/q and the cumulative production time by t = t 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 245 Exercise 14 Based on the flowing data, perform oil production forecast: Transient flow period (Suppose a reservoir can produce oil under transient flow for the next months) Pseudo–steady single-phase flow period (bubble point pressure = 4500 psi Pseudo–steady two-phase flow period when reservoir pressure declines from 4500 psi to 2500 psi 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 246 Exercise 14 (cont’d) 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 247 GEOPET BACHELOR PROGRAM PETROLEUM ENGINEERING The End 12/15/2017 Mai Cao Lân – Faculty of Geology & Petroleum Engineering - HCMUT 248