Study On EOR Method Of Condensate Reservoir In M Block

Condensate reservoirs are special oil and gas reservoirs between oil reservoirs and pure gas reservoirs formed under certain geological environments such as reservoir,hydrocarbon composition,temperature and pressure.The research object of this paper is block M of a condensate reservoir.In the middle and late stages of its development,because the formation pressure is lower than the dew point pressure,a series of problems such as reverse condensate pollution in the reservoir,insufficient formation energy,poor development effect and low recovery rate of condensate oil and gas will occur.Therefore,it is very important to study the method of improving the recovery of condensate oil and gas in block M.This paper mainly uses the combination of reservoir engineering and numerical simulation to carry out related research on the method of improving the recovery of condensate oil and gas in block M.Firstly,the development status analysis and phase characteristics experimental research of block M are carried out to clarify the current problems in block M,and to identify the change characteristics of fluid phase state and the change law of fluid property parameters of oil and gas reservoirs.Secondly,using geological interpretation data and reservoir dynamic development data,a three-dimensional geological model is established,and a corresponding numerical model is established on this basis,and phase state fitting(PVTi fitting)and history matching of production performance data are completed.Then,the distribution of the remaining oil and gas saturation is studied and the characteristics of the origin of the remaining oil and gas are analyzed.Finally,through the research on several domestic and foreign methods to relieve the condensate pollution phenomenon and improve the recovery rate of condensate oil and gas reservoirs,CO₂huff and puff,methanol+gas injection huff and puff and other gas injection methods are selected for optimization and adjustment to determine the most suitable The technical method of M block.According to the characteristics of the condensate reservoir in block M,the CO₂huff and puff method was finally adopted.The optimization results show that the injection-production well pattern adopts the three-injection and four-production mode,the gas injection rate is 10000m³/d,the injection pressure is 30MPa,and the injection-production ratio is 1.2.A total of 5schemes have been designed,namely the basic scheme,the conversion scheme,the conversion injection+new well scheme,and the conversion injection+new well+gas injection scheme.The optimal scheme is transfer injection+new well+gas injection scheme,the cumulative oil production is 4.52×10⁴t more than the basic scheme,and the recovery degree of condensate oil is increased by 1.83%.The research results provide theoretical support for further improving the recovery of condensate oil and gas in block M condensate oil and gas reservoirs.