Logging evaluation of shale laminae: A case study from the Wufeng-Longmaxi formations in the southern Sichuan Basin

• Published in: 地质科技通报 Vol. 42; no. 6; pp. 281 - 296
• Main Authors: Yuhan Tan, Fengsheng Zhang, Yabin Yao, Heng Wu, Tao Nian
• Format: Journal Article
• Language: Chinese
• Published: Editorial Department of Bulletin of Geological Science and Technology 01-11-2023
• Subjects: evaluation methods; geophysical logging; shale laminae; sichuan basin; wufeng-longmaxi formations
• ISSN: 2096-8523
• DOI: 10.19509/j.cnki.dzkq.tb20220385

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. Methods 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. Results It is concluded that the target formation has developed four types of bed, includingthe silicic bed (lamina poorly developed), silicic lamina, calcareous lamina, and argil