塔里木盆地沙雅隆起草湖凹陷三叠系划分对比

Stratigraphic classification and correlation of Triassic in Caohu Sag of Shaya Uplift, Tarim Basin

蔡习尧 魏玲 田纹全 杨玉芳 赵丽娜 成俊峰

Cai Xiyao Wei Ling Tian Wenquan Yang Yufang Zhao Lina Cheng Junfeng

中国石油化工股份有限公司石油勘探开发研究院, 北京, 100083 2. 中国石油化工股份有限公司西北油田分公司勘探开发研究院, 乌鲁木齐, 830011

SINOPEC Exploration & Production Research Institute, Beijing 100083, China 2. Research Institute of Exploration & Production, SINOPEC Northwest Company, Urumqi, Xinjiang 830011, China

塔里木盆地草湖凹陷三叠系发育较齐全,沉积厚度大,但地层划分对比精度低,已成为制约该区油气勘探的重要因素之一。根据多口钻井样品获得的丰富孢粉化石资料建立了4个孢粉组合,即Lundbladispora-Limatulasporites-Taeniaesporites,Punctatisporites-Aratrisporites-Calamospora,Apiculatisporis-Rugulatisporites-Colpectopollis,Dictyophyllidites-Aratrisporites-Alisporites组合。将草湖凹陷三叠系划分为3统3组5个段,自下而上为下统柯吐尔组(进行了重新厘定,上、下段)、中统阿克库勒组(上、下段)与上统哈拉哈塘组。各段的岩电特征十分明显,柯吐尔组下段上部的"纯泥岩段"及哈拉哈塘组上部的"大泥巴"为区域对比标志层,中、下三叠统之间存在地层缺失。层序地层共划分为3个Ⅱ级、5个Ⅲ级层序。以生物地层为依据,结合岩石地层、层序地层与测井地层,对该区三叠系进行了详细的地层划分与对比,从而为沉积相、构造运动及油气成藏等其它学科的深入研究奠定了地层学基础。

Triassic was found well-developed and thick in the Caohu Sag of the Tarim Basin;however,stratigraphic classification was not precise,restricting petroleum exploration.According to the study of plentiful of Triassic sporopollen fossils in mudstones from several wells,4 sporopollen fossil assemblages were established,including Lundbladispora-Limatulasporites-Taeniaesporites,Punctatisporites-Aratrisporites-Calamospora,Apiculatisporis-Rugulatisporites-Colpectopollis,and Dictyophyllidites-Aratrisporites-Alisporites.Triassic was divided into three series,three formations and five members.From bottom to top,there are the Ketuer Formation(it was revised as the upper and lower segments)in the lower series,the Akekule Formation(the upper and lower segments)in the middle series and the Halahatang Formation in the upper series.Lithologic and logging characteristics are obvious in each member.The "pure mudstone segment" at the top of the lower member of the Ketuer Formation and the "big mud" at the top of the Halahatang Formation were regarded as the key beds in this area.There is lacuna between the lower series and the middle series.Triassic was divided into three second-order sequences and five third-order sequences.Based on biostratigraphy,combined with rock stratigraphy,sequence stratigraphy and logging strata,Triassic in the area was classified and correlated more precisely,providing data for the analyses of sedimentary facies,tectonic movement and petroleum accumulation.

中国石化重点科技攻关项目(P08047)

https://doi.org/10.11781/sysydz201206564