Exploration and Practice of Efficient Drainage and Expansion Technology for Building Gas Reservoirs in Layered Water Flooded Reservoirs

Bohai Bay has a large demand for future reservoir construction, and there is a scarcity of high-quality gas reservoir construction resources, reservoir construction is the subsequent growth point of gas storage capacity, reservoir reconstruction reservoir as an effective way of gas storage, through the gas-driven drainage technology to achieve the expansion of capacity, not only to improve the reservoir's peak shifting capacity, but also to increase the economic value of the reservoir, but the drainage of the expansion of the process of the three-phase oil, gas and water interaction drive, the osmotic mechanism is complex, in order to improve the In order to improve the reservoir recovery rate and accelerate the construction of gas storage, multi-cycle injection and extraction core replacement experiments and numerical simulations have been carried out to study the space utilization law of reservoir construction in layered water-flooded reservoirs. The study shows that: ① Injection and extraction method, replacement method and well network deployment are the main factors affecting the utilization efficiency of storage space in layered waterflood reservoirs. ② Interactive injection and extraction rolling drive effect is better than single injection and extraction, the first round of large-scale gas extraction new drilling and extraction wells produce 17,000 tons of liquid. ③ Interlayer pressure difference has a greater impact on the effect of gas and oil reservoir combined drainage wells, there is a pressure threshold, the oil reservoir and gas reservoir pressure is higher than the threshold oil reservoir began to produce liquids. ④ Injection and extraction parameters have a large impact on pore space utilization. Liquid drainage efficiency can be improved by strengthening the research on the law of leading edge transport and control countermeasures of gas drive, optimizing the production pressure difference between the two ends of injection and extraction, and optimizing the rate of liquid extraction. ⑤ Differentiated fluid drainage and capacity expansion was implemented, with zone management by fluid zones, synchronized injection and extraction by wells and layers, and sequential shutdown, adding 20,000 tons of oil and forming a reservoir capacity of 310 million cubic meters of drained fluids. ⑥ The intensity of fluid drainage has reached the program design, and the core parameters of reservoir construction, such as kwanbo and coefficient and gas drive efficiency are basically in line with the indoor test, and the effect of liquid discharge and capacity expansion is beginning to be realized.