EXPERIMENTAL STUDY ON THE EFFECT OFGAS INJECTION ON THE OIL REPLACEMENT INFRACTURE-CAVITY RESERVOIRS

摘要

In view of the characteristics of fracture-cavity reservoirs such as severe heterogeneity, complex fluid distribution, multi-scale nature and connectivity diversity of fracturc-cavity reservoirs, for high-water cut reservoirs in the later period, it is diflficult to meet the development needs with only water injection measures. Reservoir gas injection can improve the development effect and increase cmde oil recovery rate. Therefore, through the single-well physical model gas injection oil replacement experiment, the effects of bottom water and gas injection method and oil-containing volume on the gas injection effect were studied. The results show that the bottom water energy can be used to drive oil when the bottom water is sufficient. When the gas injection cycle is the same, the oil recovery rate of the oil reservoir with sufficient bottom water is 9.13% higher than that without bottom water. In the case of sufficient bottom water, the effect of pure gas injection and stimulation method is 10% higher than the mixed water-gas injection and about 10.32% higher than that of alternate injection of gas and water slugs. Under the same gas injection conditions, the gas injection effect of the resewoir with large oil volume is 6.85% higher than that of the resewoir with small oil volume.