Optimization Of Gas Injection Technology For Tight Reservoir In X2 Area

X2 area is a typical tight oil reservoir in Ordos Basin,with poor reservoir properties,small ground-filling pressure difference and insufficient natural energy.The previous depletion development test showed the development characteristics of fast decreasing production and low recovery rate.In order to improve the effect of reservoir development in X2 area,there is an urgent need to carry out research on the optimization of technical countermeasures for gas injection development in target reservoirs.The paper first summarizes three dynamic models for producing wells in the target reservoir based on development dynamic characteristics:Integrating static data such as logging,geology,analysis and assay,and reservoir dynamic mode.The fine geological study of the target reservoir was carried out,a three-dimensional geological model of the reservoir was established,and the geological main control factors of different development dynamic modes were analyzed.Then,numerical experiments were used to investigate the dissolution mechanism,expansion mechanism,crude oil viscosity reduction mechanism,and crude oil mixing mechanism between the injected gas medium and crude oil during the gas injection development of tight reservoirs,laying the theoretical foundation for the gas injection development of the target reservoir.It also deeply compared and analyzed the differences of four gas media commonly used in the mine,such as CO₂,CH₄,BSQ1 and BSQ2,on the development effect of the target reservoir,and then preferably selected the gas injection media suitable for the target reservoir.Finally,using the reservoir numerical simulation technology,the evaluation study of gas injection method for three production dynamic mode wells was carried out with oil production and recovery rate as the main evaluation index,and the technical parameters of gas injection such as daily gas injection volume,gas-water ratio and production cycle ratio were optimized,and the effects were predicted.The research results of the paper provide technical support for gas injection development of tight reservoirs in the X2 area,and also provide a reference for gas injection development of similar tight reservoirs.