Experimental and Optimization Study of In-Situ Combustion in Jinjia Strongly Sensitive Heavy Oil Reservoir

In-situ combustion (ISC) is an important means to improve oil recovery after steam stimulation. Jinjia oilfield has entered the end of steam stimulation, so it is urgent to change the development mode. Experiment of indoor thermal analysis and one-dimensional physical simulation experiment show that the underground ignition temperature of Jinjia crude oil is 390–450 ℃, which can form 450–500 ℃ high-temperature stable heat transfer front and have good conditions for the implementation of in-situ combustion. The results of numerical simulation show that the optimal gas injection rate is 15000 Nm3/D at the initial stage of ignition for ISC development in Jin10 block; According to the optimized fire flooding scheme, through numerical simulation verification, the recovery factor of fire flooding can be increased by 45.5% on the basis of steam stimulation, which indicates that Jinjia oilfield has the potential of greatly improving oil recovery after implementing fire flooding development.