有限底水驱气藏气水均衡同采的实例评价

Cases analysis and evaluation of gas-water proportionally simultaneous production for limited bottom water-drive gas reservoirs

为提高有水气藏的采收率,在物质平衡原理分析的基础上,提出了一种与水驱气藏常规开采方式(排水采气)不同的思路——气水均衡同采。具体地讲,就是在气田开发初期、气藏尚未发生严重水侵之前,进行主动排水。在含气区采气的同时,也在含水区排水,使两区的地层压力均衡下降、气水界面保持稳定,使水驱变为纯气驱。实例分析证实,气水均衡同采是一种理论与技术上均可行的水驱气藏有效开采方式,具有明显的技术优势。该开采方式避免了选择性水侵的发生,大大提高了宏观上的波及系数和微观上的驱替效率,基本消除了水锥现象的发生,从而提高了气藏的最终采收率。该研究成果为改善水驱气藏的开采效果提供了新的技术思路。

To increase the recovery rate of water-drive gas reservoirs,based on an analysis of the material balance principles,the technology of gas-water proportionally simultaneous production is presented hereby which is distinguished from the conventional method of drainage gas recovery.In detail,in the early stage of gas field development while the water invasion in the gas reservoir is not very acute,active water drainage will be carried out.Gas production is carried out in gas region;simultaneously,water drainage is carried out in aquifer region.In this way,formation pressures of gas and water regions will decrease in balance,the gas/water interface will be kept stable,as a good result,the water drive will totally be turned into gas drive.An analysis of real cases show that gas-water proportionally simultaneous production is a method with excellent technical advantage that is both theoretically and practically applicable.With this method,selective water invasion will be avoided;both macroscopic sweep efficiency and microscopic displacement efficiency are increased greatly;coning is almost eliminated,thus the ultimate recovery rate of gas reservoirs will be improved.This study has provided novel technical solutions to improve the development of water-drive reservoirs.