摘要
纹层制约着页岩储层的品质和压裂效果,而传统纹层研究依靠的是地质资料,充分挖掘测井数据中蕴含的页岩纹层信息可以为钻孔页岩纹层评价提供新的思路和方法。依托四川盆地南部五峰组-龙马溪组页岩的取心钻孔,基于岩心、全直径岩心CT、大尺寸薄片、全岩衍射和有机碳含量厘定的纹层组构特征,通过地质刻度测井,从元素扫描、电成像、阵列声波、常规和核磁共振测井中提取表征页岩纹层不同属性的测井信息,阐述页岩纹层测井评价的方法体系。研究指出目的层主要发育了富硅质弱纹层、富硅质纹层、富钙质纹层和富黏土纹层4种纹层类型。元素扫描测井用于确定纹层矿物组分和有机碳含量。电成像、阵列声波各向异性指数和常规测井用于评价纹层密度或发育程度。电成像指示纹层厚度,而核磁共振侧重分析纹层的孔隙结构变化。测井分辨率和响应的多解性虽然制约着页岩纹层的测井解释精度,但基于岩石物理属性出发的各类测井方法是页岩纹层以及纹层组评价的有益补充。
Shale laminae influence shale reservoir quality and fracturing,whereas previous studies are simply based on geological materials.Taking full advantage of geophysical logging data could provide novel insights for shale laminae evaluation in drilled boreholes.Cored boreholes in the Wufeng-Longmaxi formations in the southern Sichuan Basin are utilized in this study.Shale cores,CT scanning based on full-diameter cores,large-sized thin sections,X-ray diffraction,and TOC content are first integrated to clarify shale laminae fabrics.Elemental scanning,microresistivity electrical imaging,multipole array acoustic,conventional and nuclear magnetic resonance logging techniques are interpreted to characterize shale laminae by geological calibration,and the methodology of logging evaluation on shale laminae has been set out.It is concluded that the target formation has developed four types of bed,includingthe silicic bed(lamina poorly developed),silicic lamina,calcareous lamina,and argillaceous lamina.Elemental scanning is implemented to determine laminae minerals and TOC content.Electrical imaging and the anisotropy index derived from multipole array acoustic and conventional logs are used to evaluate lamina density or development degree.Besides,electrical imaging is able to reflect the lamina thickness.Nuclear magnetic resonance is performed to analyze the variation in lamina pore structure.Although logging resolution and response complexity can significantly affect the accuracy of logging interpretation of shale laminae,logging techniques rooted in petrophysical properties are valuable supplements for the evaluation of shale laminae and lamina associations.
作者
谭玉涵
张凤生
姚亚彬
吴恒
年涛
Tan Yuhan;Zhang Fengsheng;Yao Yabin;Wu Heng;Nian Tao(Geological Research Institute,CNPC Logging Company Limited,Xi′an 710000,China;Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang 050031,China;School of Earth Sciences and Engineering,Xi′an Shiyou University,Xi′an 710065,China)
出处
《地质科技通报》
CAS
CSCD
北大核心
2023年第6期281-296,共16页
Bulletin of Geological Science and Technology
基金
油气资源与工程全国重点实验室开放课题资助(PRE/open-2303)
中石油“昭通-长宁区块页岩储层纵横向甜点测井综合评价”课题(CPL2021-B05)。
