低渗透底水气藏水侵动态模拟实验及其对采收率的影响  

Simulation experiment of water invasion performance in low-permeability bottom water gas reservoir and its influence on recovery factor

作　　者：高树生[1,2] 杨明翰 叶礼友 刘华勋[1] 朱文卿 GAO Shusheng;YANG Minghan;YE Liyou;LIU Huaxun;ZHU Wenqing(PetroChina Research Institute of Petroleum Exploration&Development,Langfang,Hebei 065007,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国石油勘探开发研究院 [2]中国科学院大学

出　　处：《天然气工业》2022年第3期61-70,共10页Natural Gas Industry

基　　金：中国石油天然气股份有限公司科学研究与技术开发项目“不同类型气藏采收率标定与提高采收率机理研究”(编号:2021DJ1701)。

摘　　要：水侵是底水气藏衰竭开发的常态,而水侵对于气藏开发动态有何影响,又如何影响采收率是气藏开发关注的重点和难点。根据气藏构造及底水水侵特征,设计出入口之间多测压点的实验流程,运用带有多个测压点的长岩样模拟低渗透底水气藏衰竭开发动态过程,研究均质和纵向非均质底水气藏的水侵动态、规律及其对采收率的影响。研究结果表明:(1)均质气藏衰竭开发过程中底水侵入动态受储层渗透率影响明显,渗透率在0.1 mD左右或更致密时,底水侵入非常缓慢,水体能量补充有效性不足,废弃压力决定于渗透率,对采收率影响不大;相反,渗透率越高,水侵越快,水体能量有效性强,见水越早,废弃压力越高,采收率明显降低。(2)纵向非均质底水气藏的水侵动态受控于不同渗透率储层的叠置模式,致密储层接近于底水可有效延缓水侵速度,降低废弃压力,提高采收率;相反,水侵速度加快,废弃压力高,采收率低。结论认为,运用物质平衡方程导出的底水气藏采收率计算模型可以准确拟合岩样的开发动态特征与采收率,气藏开发实例证明了采收率模型对于底水气藏水侵开发动态及采收率预测的有效性。Water invasion is a normal state during the depletion development of bottom water gas reservoirs.How water invasion influences the development performance of gas reservoirs and the recovery factor is the focus and difficulty of gas reservoir development.In this paper,the experimental process with multiple pressure measuring points between inlet and outlet is designed according to the structural characteristics of gas reservoirs and the invasion characteristics of bottom water.A long core with multiple pressure measuring points is used to simulate the depletion development dynamic process of low-permeability bottom water gas reservoirs.In addition,the water invasion performance and laws of homogeneous and vertically heterogeneous bottom water gas reservoirs and its influences on recovery factors are studied.And the following research results are obtained.First,the invasion performance of bottom water during the depletion development of homogeneous gas reservoir is obviously affected by reservoir permeability.When the permeability is about 0.1mD or lower,the invasion of bottom water is very slow,and the supplement effectiveness of water energy is insufficient,so the abandonment pressure is dependent on permeability and the recovery factor is little influenced.On the contrary,the higher the permeability,the faster the water invasion,the more effective the water energy,the earlier the water breakthrough,the higher the abandonment pressure and the greater the decrease of recovery factor.Second,the water invasion performance of vertically heterogeneous bottom water gas reservoir is controlled by the superposition mode of reservoirs with different permeabilities.If the tight reservoir is close to the bottom water,the water invasion speed slows down effectively,the abandonment pressure decreases and the recovery factor increases.On the contrary,the water invasion speed is increased,the abandonment pressure is high and the recovery factor is low.In conclusion,the recovery factor calculation model of bottom water gas reser

关 键 词：底水气藏 水侵动态 模拟实验 储集层 非均质性 低渗透 致密 废弃压力 采收率 

分 类 号：TE37[石油与天然气工程—油气田开发工程]