确定水驱气藏废弃压力与可采储量的简便方法

Easy determination of abandonment pressure and recoverable reserves for gas reservoirs with water drive

刘世常 李闽 巫扬 于春生

Liu Shichang Li Min Wu Yang Yu Chunsheng

西南石油大学,油气藏地质及开发工程国家重点实验室, 成都 610500; 中国石油四川石油管理局川东开发公司, 重庆 400021

State Key Laboratory of Reservoir Geology and Exploitation·Southwest Petroleum University, Chengdu 610500; East Sichuan Production Company, Sichuan Petroleum Administration Bureau, PetroChina, Chongqing 400021

水驱气藏的废弃压力和可采储量是确定采收率的关键参数, 它们的大小直接影响到气藏采收率的高低, 因此如何准确计算水驱气藏废弃压力与可采储量的大小显得非常重要。引入虚拟曲线法, 根据容积法地质储量计算公式, 推导出水驱气藏的视废弃地层压力与可采储量关系式。应用生产动态数据绘制水驱气藏压降储量曲线与虚拟曲线于同一图中, 压降储量曲线延长线和虚拟曲线的交点即是水驱气藏的废弃压力点。该点对应的压力即是水驱气藏的废弃压力, 对应的累计产气量为可采储量。

Abandonment pressure and recoverable reserves are the key parameters to determine recovery efficiency of a gas reservoir with water influx. Their values directly affect gas recovery efficiency. Therefore it is so important to obtain accurate data of abandonment pressure and recoverable reserves for a gas reservoir with water influx. This article presents the imaginary line method. First we can derivate the equation of pseudo abandonment pressure and recoverable reserves using volumetric method. Then plot p/z curve and imaginary line by applying the production performance data, the two curves will bring up an intersection, this intersection is the abandonment point, then we can calculate abandonment pressure and recoverable reserves using this abandonment point.