页岩气藏注CO2渗透率界限及开发参数优化  

Permeability Demarcation and Process Parameter Optimization of Shale Gas Recovery on CO2 Injection

作　　者：卫诗豪 段永刚 蒋天遥 李政澜 伍梓健 WEI Shi-hao;DUAN Yong-gang;JIANG Tian-yao;LI Zheng-lan;WU Zi-jian(Petroleum Engineering School,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]西南石油大学石油与天然气工程学院,成都610500

出　　处：《科学技术与工程》2020年第25期10262-10267,共6页Science Technology and Engineering

基　　金：国家科技重大专项(2016ZX05037-006)。

摘　　要：根据页岩气井的现场生产情况,压裂水平井产量会迅速下降,注CO 2技术是改造储层提高产量的有效手段。连续驱替与吞吐式注入作为注CO 2提高页岩气采收率的两种常见方式,却在相同页岩气藏中驱替效果存在差异。为了对不同储层条件下注CO 2开发方式进行优选,基于现场页岩气藏实际情况建立了双孔介质气藏机理模型,并通过建立采收率影响因素的正交试验,分析了渗透率、孔隙度、储层厚度、CH 4和CO 2最大吸附量以及Langmuir压力等的影响规律。将渗透率作为主控因素,划分了5个不同渗透率条件,进行直接驱替与吞吐注CO 2模拟,并针对不同CO 2注入驱替开发方式进行了布缝模式、井位排列、闷井时间等开发参数优化。结果表明:不同渗透率条件下两种开发方式驱替效果不同,以0.001 mD为界限,渗透率低于0.001 mD时,直接驱替效果更优;渗透率高于0.001 mD时,选择吞吐式注CO 2为宜;针对连续注气,交叉布缝模式具有更高的采收率,在多井同产同注时,应将生产井置于内部;另外,吞吐式注气应该选择较短的焖井时间来节约成本获得更好的经济效益。According to situations in the shale gas reservoir,production will decrease rapidly in fractured horizontal well.Continuous injection and huff-n-puff injection are commonly used to develop shale gas reservoir,but the results are different.In order to optimize the way of CO 2 injection under different reservoir conditions,based on the actual situation of shale gas reservoir,a mechanism model of dual-porosity and dual-permeability was established.By established orthogonal test,the influence law of permeability,porosity,thickness of reservoir,methane maximum absorption,carbon dioxide maximum absorption and Langmuir pressure were studied.As permeability as the main control factor,five different permeability conditions were divided to simulate continuous injection and huff-n-puff CO 2 injection.In addition,the technological parameters such as cloth pattern,well location and soak time were optimized according to different CO 2 injection.The results show that the continuous injection effect is better when the permeability is lower than 0.001 mD and the huff-n-puff CO 2 injection is better when the permeability is higher than 0.001 mD.For CO 2 continuous injection,the cross pattern has a higher recovery rate,and the production wells should be placed inside when multiple wells are simultaneously produced and injected.In addition,the CO 2 huff-n-puff injection should choose shorter soaking time to save cost and get better economic benefits.

关 键 词：页岩气 CO2驱替 CO2吞吐 渗透率界限 正交试验 数值模拟 

分 类 号：TE348[石油与天然气工程—油气田开发工程]