渝西地区五峰组—龙马溪组深层页岩储层力学脆性的非均质性特征——以Z-3井为例  

Heterogeneity of mechanical brittleness in Wufeng-Longmaxi shale reservoirs in western Chongqing area——Using well Z-3 as an example

作　　者：魏源 赵迪斐[1,2,3,4] 焦伟伟 张海杰 WEI Yuan;ZHAO Difei;JIAO Weiwei;ZHANG Haijie(School of Resources and Earth Science,China University of Mining and Technology,Jiangsu Xuzhou 221116,China;Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,the Ministry of Education,China University of Mining and Technology,Jiangsu Xuzhou 221008,China;Shandong University of Science and Technology,Shandong Key Laboratory of Depositional Mineralization and Sedimentary Mineral,Shandong Qingdao 266590,China;Chongqing Institute of Geology and Mineral Resources,Key Laboratory of Shale Gas Exploration,Ministry of Natural Resources,Chongqing 401120,China;Chongqing Shale Gas Exploration and Development Co.,Ltd.,Chongqing 401121,China)

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]煤层气资源与成藏过程教育部重点实验室,江苏徐州221008 [3]山东科技大学山东省沉积成矿作用与沉积矿产重点实验室,山东青岛266590 [4]重庆地质矿产研究院页岩气勘探开发国家地方联合工程研究中心,重庆401120 [5]重庆页岩气勘探开发有限责任公司,重庆401121

出　　处：《非常规油气》2021年第1期67-76,共10页Unconventional Oil & Gas

基　　金：重庆页岩气公司科研项目“不同来源石英对页岩储层物性和含气性的控制作用研究”(CYS-FW-2019-0099);刘宝珺地学青年科学基金“五峰组-龙马溪组页岩沉积“精细微相”特征及其对储层发育的控制”(DMSMX2019002);国家自然科学基金项目“海相页岩储层纳米级储集空间精细定量解剖”(41772130;41804106);国家重点基础研究发展计划(973)项目“页岩微孔缝结构与页岩气赋存富集研究”(2012CB214702);江苏省自然科学基金青年基金项目“基于裂隙尖端放电机制的深部岩体损伤自电特征研究”(BK20170274);重庆市绩效激励引导专项“页岩含气量差异性分布影响因素”(cstc2018jxj190002);中国矿业大学资源学院大学生学术科研中心科研训练项目“深层页岩储层力学脆性非均质性表征”(CSA-201902)。

摘　　要：为了研究储层力学脆性对层段优选的作用,针对页岩储层力学脆性的非均质性特征,以渝西地区Z-3井五峰组—龙马溪组页岩储层为例,通过手标本观测、岩石薄片观测、扫描电镜观测、X射线衍射、单轴抗压实验、三轴抗压实验、巴西抗拉强度等储层分析手段,测试评价储层的力学脆性特征,并表征其层段非均质性。结果表明,深层页岩储层物性受特殊储层成岩作用影响非均质性相对减弱,其评价需要不同于中浅部储层的新指标体系。综合峰前、峰后曲线特征的脆性指数和脆性矿物比例参数两种评价方式,可得五峰组—龙马溪组底部是相对优质的力学脆性层段;受沉积环境、矿物组分与沉积分异、差异成岩作用等因素的控制,五峰组—龙马溪组页岩储层具有力学脆性非均质性,主要体现在储层的矿物组分比例、微观沉积特征及力学脆性特征具有横向稳定的层段性差异,可以作为页岩气压裂层段优选与勘探开发的科学依据。In order to study the effect of reservoir mechanical brittleness on interval optimization,aiming at the problem of the mechanical brittleness heterogeneity of shale reservoir.Based on specimen observation,thin section observation,SEM observation,X-ray diffraction,uniaxial/triaxial pressure experiment,brazilian tensile strength test,et al,samples of shale reservoir from the Z-3 well of Wufeng-Longmaxi formation in western Chongqing area is studied in order to evaluate the mechanical brittleness of reservoir and characterize its heterogeneity.The results show that the heterogeneity of deep shale reservoirs is relatively weakened under the influence of special reservoir diagenesis,and its evaluation needs a new index system different from that of middle-shallow reservoirs.The best optimum method of interval brittleness evaluation should combine the brittleness index of pre and post peak curves with the proportion parameter of brittle minerals.Accordingly,the bottom of Wufeng-Longmaxi formation is a relatively high-quality mechanical brittle interval.Controlled by depositional environment,mineral composition,sedimentary differentiation,the shale reservoir of Wufeng-Longmaxi formation has mechanical brittle heterogeneity and it is mainly shown that mineral content,microscopic distribution characteristics and the mechanical brittleness characteristics have obvious horizontal stable interval differences.Thus,it can be used as a scientific basis for interval optimization for shale gas fracturing and exploration.

关 键 词：页岩储层 力学脆性 非均质性 储层评价 龙马溪组 五峰组 

分 类 号：P583[天文地球—岩石学] TE132[天文地球—地质学]