The Evaluation of Feasibility of Advanced Gas Injection by CO_2 Flooding in Low Permeability Reservoir

Starts from the mechanism of advanced water injection,combines with the numerical simulation and actual production data,the pressure profiles under the different injection mode is contrasted. The water injection timing in ultra low permeability reservoirs,and under the optimal water injection timing is optimized. The effect on transmission of pressure by different ways of advanced gas injection,builds the effect evaluation method of different injection ways is analyzed. Based on low permeability reservoirs property exists start-up pressure gradient,stress the sensitive,thin pore throats,the effect on the lifting amplitude of oil wells,gas injection wells and the oil recovery and miscible affection by the different ways of advanced injection is analyzed. Advanced gas injection solves the poor effect of advanced water injection and the practical phenomenon of oil well critical flooding. Taking Daqing YSL oilfield for example,the development effect has been analyzed under the different gas injection,and the development effect of the method of advance gas injection,which has certain directive significance to set the technology policy is evaluated.