Development Strategy Study and Practice of Thin Bottom-water Oil and Gas Reservoirs in Xihu Sag, East China Sea

Achieving balanced water invasion is the key to slowing down the water invasion rate of thin bottom-water oil and gas reservoirs, prolonging the water-free gas production period and improving the development effect. In this paper, the mechanism model is used to study the development strategy of thin bottom-water oil and gas reservoirs, including well type, horizontal well length, completion method, water avoidance height and production rate. Also the development practice in Xihu Sag of East China Sea is summarized. The study shows that horizontal wells combined with variable density oriented perforation is the key technology to develop thin bottom-water oil and gas reservoirs. It is very important to control the speed of oil and gas production. The length of horizontal well and the height of water avoidance have a significant impact on the development effect. A reasonable development strategy can extend the water-free period for 3 years and increase the recovery rate by 5%. The successful development practices in Xihu Sag of East China Sea can provide some reference for the efficient development of such reservoirs.