Mixture Gas Flooding Mechanism In Carbonate Reservoirs And Optimization Of Development Parameters

Carbonate oil and gas reservoirs are widely distributed worldwide.Among them,low-permeability volatile oil carbonate reservoirs are difficult to inject water and have high gas-oil production ratios.Aiming at this type of reservoir,the development of produced gas injection is gradually attracting the attention of scholars at home and abroad.Most experts and scholars have conducted a lot of research on the mechanism of gasliquid miscible formation during gas injection,the characteristics of crude oil phase changes,and the optimization of injection and production parameters in low pressure reservoirs and abnormal high pressure reservoirs through experiments and theoretical methods.The thesis focuses on the typical carbonate reservoirs in Kazakhstan,and conducts research on gas injection development.The Jean-Najor reservoir is a low-permeability and low-pressure carbonate reservoir.It is currently in the late stage of waterflood development.Due to the serious heterogeneity of the reservoir,poor water-injection capacity of water-injection wells,poor oil production capacity of production wells,and poor crude oil flow capacity At present,the reservoir pressure is kept at a low level.At present,it is considered to use the produced gas as a gas source for reinjection to supplement the formation energy and improve the development effect.The Kasha dry oil reservoir is an abnormally high-pressure and low-permeability carbonate reservoir.At present,gas injection development is considered.Aiming at the problems in the above development process,the paper carried out research from the perspectives of volatile oil gas injection mechanism,factors affecting gas injection development,and optimization of gas injection development parameters,and obtained the following conclusions:(1)Compound gas forms miscibility with crude oil in the reservoir according to the phase equilibrium theory.(2)Through numerical simulation calculation,the minimum miscible pressure of the produced gas in Naror Oilfield is 22.03 MPa.The minimum miscible pressure of Kasha dry produced gas is 28.5 MPa.(3)Taking typical well groups of carbonate reservoirs as the research object,starting from the reservoir well pattern parameters and fracture parameters,the recovery rates in low-pressure reservoirs and abnormal high-pressure reservoirs are analyzed along with the reservoir well pattern parameters and oil.Changes in Tibetan development parameters.(4)Taking typical well groups of carbonate reservoirs as research objects,the reservoir development parameters are optimized,and reasonable development parameters under different reservoir well pattern parameters and fracture parameters are optimized,the final numerical simulation results are similar to those of the development technology board.