Optimization Design Of Gas Injection Scheme For Donghe 1C? Reservoir

After the integration of clastic reservoir into the high water cut and high oil recovery development stage,it is faced with the challenges of increasing water cut,decreasing production and insufficient reserve resources.It is difficult to maintain stable production.Tarim oilfield is affected by the unfavorable factors such as deep buried depth,high temperature,high salinity,thin well network and so on,so the enhanced oil recovery is facing great challenges.Through improving the pre-evaluation of recovery ratio technology,gas injection EOR can not be limited by the severe conditions of reservoir high temperature,high salinity and other reservoirs.it is easy to realize miscible displacement in high pressure condition.The Tarim oilfield is rich in natural gas resources,and gas injection is the practical technology direction to improve oil recovery in high temperature and high salt reservoirs.The basic idea by combining geology,reservoir engineering and numerical simulation,using the related knowledge of reservoir engineering on the distribution of remaining oil reservoir is studied,the minimum miscibility pressure was determined by tube test,through long core displacement experiment tested the injection of gas and gas injection rate on the influence of mining.The miscible mechanism of gas injection is simulated by numerical simulation.On the basis of the 1 mining Donghe reservoir geological characteristics,effect,combined with the fine depiction of gas injection and the results of the laboratory evaluation,focusing on the optimization method of gas injection parameters of gas production,design,selection of appropriate test area and gas injection layer,comparing the different well spacing,different well types and different gas injection rate for gas injection and production capacity,design and optimization of development scheme,and ultimately get the best gas injection scheme 1CIII Donghe reservoir.Research shows that Donghe oilfield associated gas and dry gas injection can achieve miscible gas injection(1mL/h);low end high sweep efficiency;with 40×10~4m~3/d gas injection,gas injection time should be 5 years;the top of the gas injection flooding,gravity assisted local area flooding supplemented by miscible flooding method new injection wells and production wells;should adopt horizontal well,from 400 meters above the injection well;gas injection wells should be located in the 1~2+1~3 layer,new wells should be located on the 1 sand group edge and 2 sand group;injection production ratio is 1.3 and the recovery rate is 2%~3%.Through the tracking analysis of the production situation of the gas injection test well group,it is proved that the gas injection development effect is remarkable,it is clear that the main technical direction of improving the recovery ratio for the"three-high"reservoir of clastic rock.