库拜煤田阿艾矿区煤储层地应力特征及其对储层物性的制约  

In-Situ Stress Characters of CBM Reservoir in the Flexure Basin of Kubai Coalfield and Its Constraints on Reservoir Physical Properties

作　　者：李鑫 魏永恒 王文峰 琚宜文[2,3] 田继军 吴斌 冯烁 LI Xin;WEI Yongheng;WANG Wenfeng;JU Yiwen;TIAN Jijun;WU Bin;FENG Shuo(Xinjiang Key Laboratory for Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt,Xinjiang University,Urumqi Xinjiang 830017,China;Key Laboratory of Computational Geodynamics of Chinese Academy Sciences,Beijing 100049,China;School of Earth Science,University of Chinese Academy Sciences,Beijing 100049,China;No.161 Geological Exploration Team,Coalfield Geology Bureau of Xinjiang Uygur Autonomous Region,Urumqi Xinjiang 830002,China)

机构地区：[1]新疆大学新疆中亚造山带大陆动力学与成矿预测自治区重点实验室,新疆乌鲁木齐830017 [2]中国科学院计算地球动力学重点实验室,北京100049 [3]中国科学院大学地球与行星科学学院,北京100049 [4]新疆维吾尔自治区煤田地质局一六一地质勘探队,新疆乌鲁木齐830002

出　　处：《新疆大学学报（自然科学版）（中英文）》2022年第6期727-735,746,共10页Journal of Xinjiang University(Natural Science Edition in Chinese and English)

基　　金：国家自然科学基金(42002188;U1903303;41872160);新疆维吾尔自治区高校科研计划(XJEDU2019Y010)。

摘　　要：地应力是影响煤层气高效开发的关键因素之一.基于南天山山前挠曲盆地库车坳陷阿艾矿区的多套煤层气储层注入/压降试井、原地应力测试、吸附气含量测试等数据以及库车坳陷构造演化史分析,阐明了阿艾矿区煤储层地应力分布特征及其对储层物性的制约,探讨了挠曲盆地构造演化对煤储层地应力的制约作用.结果表明:(1)阿艾矿区垂向上煤储层埋深处于350~500 m、500~900 m和900~1200 m时,地应力状态类型依次为σH>σv>σh、σH≈σv>σh和σv>σH>σh;(2)埋深900 m处既是垂直主应力和最大水平主应力的转换点,也是渗透率趋势变化点,暗示了储层地应力对渗透率的制约作用.阿艾矿区吸附气含量临界深度在900~1000 m;(3)喜山期的构造挤压及逆冲推覆将浅部(埋深<500 m)碎裂煤储层裂隙压实闭合,使其渗透率降低.受浅部逆冲推覆影响,中深部(埋深500~1200 m)煤储层古NS向构造挤压应力部分释放后渗透率回弹,再加上含气性较好,总体有利于煤层气开发;(4)阿艾矿区南部比尤勒包谷孜背斜煤储层地应力小于中部夏阔坦向斜水平主应力,导致比尤勒包谷孜背斜煤储层渗透率大于夏阔坦向斜煤储层渗透率,相对更利于煤层气开发.In-suit stress is one of the key factors determining the success or failure of coal bed methane(CBM)development.Based on the data of well tests,in-situ stress tests,and adsorbed gas content tests of multiple coal reservoirs of the A’ai Mining Area locating in the Kuqa Depression of the piedmont flexural basin southern Tianshan Mountain,stress distribution of the A’ai Mining Area and its constrains on physical properties of coal reservoir were clarified,and the constraints of tectonic evolution of flexure basin on in-situ stress of coal reservoir were discussed.The results showed:(1)The in-situ stress state types areσH>σv>σh,σH≈σv>σhandσv>σH>σhwhen the reservoir depth is 350~500 m,500~900 m and 900~1200 m,respectively;(2)The depth of 900 m is not only the conversion point of the vertical principal stress and the maximum horizontal principal stress,but also the transition point of permeability trend,suggesting the control effect of in-situ stress on permeability,the critical depth of adsorbed gas conversion of the A’ai Mining Area was 900~1000 m;(3)The fractures of the shallow(buried depth<500 m)coal reservoir were compacted and closed by structural compression and thrust nappe during Himalayan period,which reduced the permeability.Influenced by the shallow thrust nappe,the NS directional compressive stress of the middle and deep(buried depth of 500~1200 m)coals with relative higher gas capacities released partly,leading to the permeability rebound,thus the middle and deep coals were generally conducive to the development of CBM;(4)The coal reservoir stress of the Biyoulebaoguzi compound anticline in the south of the A’ai Mining Area was less than that of the Xiakuotan syncline in the middle,resulting in the permeability of former was greater than that of the latter.Hence the Biyoulebaoguzi compound anticline was relatively more conducive to the development of CBM.

关 键 词：挠曲盆地 煤层气 煤储层 地应力 渗透率 

分 类 号：P618.11[天文地球—矿床学]