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塔中地区志留系柯坪塔格组是该地区重要的勘探开发目的层,对其沉积体系的研究可为勘探部署提供重要的依据。综合岩心、测井和地质资料的分析,运用现代沉积学、层序地层学理论,在塔中志留系划分出3个三级层序,6个体系域,柯坪塔格组上、下沥青砂岩段分别对应于层序Ⅰ和Ⅱ的海侵体系域。对其潮坪沉积体系进行深入探讨,识别出3种沉积亚相、8种沉积微相,并建立了塔中地区柯坪塔格组低缓地形背景下的潮坪沉积模式:平面上,塔中16井区主要为潮间带亚相;塔中80—塔中31井区主要为潮下带亚相;满西2井区以潮下低能带为主。纵向上,下沥青砂岩段主要以潮下带沉积为主,上沥青砂岩段主要发育潮间带。
The Silurian Kepingtage Formation in the Tazhong area is an important target for exploration and development in this area. The study on its sedimentary system may provide an important basis for exploration and deployment. Comprehensive core, well logging and geological data analysis, the use of modern sedimentology, sequence stratigraphy theory, in the Tazhong Silurian divided into three third-order sequences, six system domains, Kepingtage group up and down Asphaltic sandstone sections correspond to the transgressive systems tract of sequences I and II, respectively. The tidal flat sedimentary system was explored in depth. Three kinds of sedimentary subfacies and eight sedimentary microfacies were identified, and the tidal flat sedimentary model under the low-lying terrain of the Kepingtage Formation in the Tazhong area was established: on the plane, Well block 16 is mainly intertidal subfacies. Well Tazhong 80-Tazhong 31 is mainly subtidal sub-facies, and Manxi-2 well is dominated by subtidal low-energy bands. Longitudinally, the lower asphaltic sandstone is dominated by subtidal sediments and the upper asphaltic sandstone mainly develops intertidal zones.