超深层致密砂岩储层孔喉结构及其动态变化特征实验研究  

Experimental study on pore throat structure and its dynamic change characteristics of ultra-deep tight sandstone reservoir

作　　者：徐朝晖[1,2] 宋雯丹 刘广峰[1,3] 李军[1,2] 王立冬 王艳丽 XU Zhaohui;SONG Wendan;LIU Guangfeng;LI Jun;WANG Lidong;WANG Yanli(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum,Beijing,Beijing 102249,China;College of Geosciences,China University of Petroleum,Beijing,Beijing 102249,China;College of Petroleum Engineering,China University of Petroleum,Beijing,Beijing 102249,China;Dina Exploration and Development Management Department,PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China;Kela Exploration and Development Management Department,PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China)

机构地区：[1]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国石油大学(北京)石油工程学院,北京102249 [4]中国石油塔里木油田分公司迪那采油气管理区,新疆库尔勒841000 [5]中国石油塔里木油田分公司克拉采油气管理区,新疆库尔勒841000

出　　处：《中国海上油气》2025年第2期164-176,共13页China Offshore Oil and Gas

基　　金：国家自然科学基金企业创新发展联合基金重点支持项目“克拉苏构造带超深层致密砂岩成储机制与甜点智能预测方法研究(编号:U24B2015)”;国家自然科学基金面上项目“致密砂岩油藏孔喉构型与微观多模态流动机理研究(编号:52274049)”部分研究成果。

摘　　要：孔喉结构是控制超深层异常高压致密砂岩气藏储层物性与气水渗流规律的核心要素。随着开发过程气藏压力的逐渐下降,岩石骨架及孔喉系统发生应力敏感性形变,孔喉结构随之发生依赖于孔隙压力的动态变化,从而影响气水渗流规律。以库车坳陷KS2气田巴什基奇克组为研究对象,结合高压压汞、恒速压汞和核磁共振等实验手段,阐明了超深层致密砂岩储层微观孔喉结构特征,根据不同孔隙压力条件下的孔喉结构表征实验明确了孔喉结构的动态变化特征。研究结果表明:在35.0 MPa围压条件下,将孔隙压力从35.0 MPa逐步降低到5.0 MPa、相应的有效应力从0 MPa提高到30.0 MPa的过程中,孔隙和喉道半径均变小,主流喉道平均半径平均降低幅度为26.0%,喉道半径下限平均降幅为24.6%;孔隙和喉道的收缩导致孔隙度和绝对渗透率分别从5.43%和0.116×10^(-3)μm^(2)降至4.66%和0.027×10^(-3)μm^(2);渗透率越低,渗透率伤害率越高,应力敏感性越强。研究结果明确了开发过程中孔隙压力降低条件下孔隙与喉道尺度、孔喉结构的定量变化特征,可为超深层致密砂岩气藏储层动态评价及气水渗流规律研究奠定基础。Pore throat structure is the core element to control the physical properties and gas-water seepage law of ultra-deep abnormally-high-pressure tight sandstone gas reservoirs.With the gradual decline of gas reservoir pressure in the development process,stress-sensitive deformation occurs in the rock skeleton and pore throat system,and the pore throat structure changes dynamically depending on the pore pressure,which thus influences the gas-water seepage law.Taking the Bashijiqike Formation of KS2 gas field in Kuqa Depression asthe research object,this study clarifies the microscopic pore throat structure characteristics of ultra-deep tight sandstone reservoirs with the experimental methods of high-pressure mercury injection,constant-rate mercury injection,and nuclear magnetic resonance.The dynamic change characteristics of pore throat structure are clarified through the pore throat structure characterization experiments under different pore pressure conditions.The results show that under the confining pressure of 35.0 MPa,when the pore pressure is gradually reduced from 35.0 MPa to 5.0 MPa and the corresponding effective stress is increased from 0 MPa to 30.0 MPa,the pore and throat radius become smaller.The average radius of the mainstream throat decreases by 26.0%on average,and the lower limit of the throat radius decreases by 24.6%on average.The shrinkage of pores and throats leads to the decrease in porosity and absolute permeability from 5.43%to 4.66%and from 0.116×10^(-3)μm^(2) to 0.027×10^(-3)μm^(2),respectively.When the permeability is lower,the permeability damage rate is higher,and the stress sensitivity is stronger.The research results clarify the quantitative variation characteristics of pore and throat scales and pore throat structure under the condition of pore pressure reduction during the development process,which can lay a foundation for the dynamic evaluation of ultra-deep tight sandstone gas reservoirs and the study of gas-water seepage law.

关 键 词：库车坳陷 巴什基奇克组 致密砂岩 应力敏感性 动态孔喉结构 

分 类 号：P618.13[天文地球—矿床学]