摘要:
准噶尔盆地西北缘三叠系一直是我国重要的油气攻关层位,然而其地层发育情况却长期存在争议,尤其是精细层位划分以及内部是否存在不整合界面的问题。本次研究结合了前人研究成果、岩性、测井、地震资料,并以野外露头研究为基础,通过对深底沟—大侏罗沟、花园沟、黑油山沟、吐孜沟、水库沟5条野外剖面的考察,识别出各类标志层以及 J/T、T/C、T3/T2、T2k2/T2k1、S6/S7界线,认为三叠系内部并不缺失 S2、S3(砂组,位于 T2k2),并可区分出此二层位,随即建立起多个野外剖面的时空对应关系;此外,本次研究还通过不同岩性岩石测井响应特征将下三叠统划分为3段6砂组,将上三叠统划分为3段7砂组,将中三叠统则更细划分为2段7砂组14小层,并通过元素地层学方法对层位进行了局部检验。
关键词:
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准噶尔
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克拉玛依
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三叠系
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地层
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界线
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测井
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地震
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元素
Abstract:
Triassic strata on the northwest margin of Junggar Basin constitute one of the most significant oil and gas strata in China. However, there has long existed much controversy concerning the development state of the strata, especially the subdivision of inner small strata and the existence or nonexistence of the unconformity. In combination with previous results, lithology, logging and seismic data, on the basis of outcrop research, and according to the field investigation along five profiles of Shendigou–Dazhuluogou, Huayuangou, Heiyoushangou, Tuzigou, and Shuikugou, the authors identified the marker beds and boundaries of J/T, T/C, T3/T2, T2k2/T2k1 and S6/S7. It is held that there is no hiatus in Triassic, and S2 and S3 can be distinguished according to outcrop characteristics. On such a basis, the Triassic stratigraphic framework is set up. Furthermore, the Lower Triassic is subdivided into 3 members and 6 sand groups, the Upper Triassic is subdivided into 3 members and 7 sand groups, and the Middle Triassic is further subdivided into 2 members, 7 sand groups and 14 small strata by analyzing the logging data. Also, the strata is partly verified according to the method of elementary stratigraphy.
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