Mechanism research on technical policy of liquid extraction depressurization development for buried hill reservoirs

Most of buried hill reservoirs are in the late stage of water flooding development, especially for this kind of reservoir with large water-oil volume ratio, it is more difficult to develop the residual oil in matrix system. This article presents a new idea about technical policy of extraction depressurization development which has not been studied in domestic and abroad, and analyses the major influence factor of liquid extraction depressurization by dual-media numerical simulation in depth. The results show that it can increase the oil production in matrix system to a greater extent by liquid extraction depressurization. The liquid extraction capacity is the most important factor which contains the effect of uniform speed liquid extraction, variable speed liquid extraction and periodic liquid extraction. Under the condition of keeping stable production, the larger the liquid volume extracted, the faster pressure dropped, and the more oil will be discharged in matrix system. According to these results, this paper suggests the reasonable technical policy of liquid extraction depressurization, and it is of great significance to obtain good effect of slowing down water cut and enhancing oil recovery in depressurization development of the buried hill reservoirs with high water cut and enough energy.