摘要
以野外露头剖面、岩心及薄片观察为基础，结合测、录井以及地震等资料，对川东地区开江—梁平海槽东侧长兴组沉积组合类型及分布规律进行了研究。结果表明：长兴组沉积组合可分为生物礁型及无生物礁型2类。其中，生物礁型沉积组合细分为台缘礁+台缘滩、台缘礁+台内滩、台缘礁+无滩、台内礁+台内滩、台内礁+无滩等5个亚类，无生物礁型沉积组合细分为无礁+台缘滩、无礁+台内滩、台缘滩+台内滩及无礁+无滩等4个亚类。长兴组发育陡坡型台缘礁及缓坡型台缘礁，2种生物礁呈现不同的沉积组合规律。前者为台缘礁+台缘滩沉积组合；而后者主要为台缘礁+无滩沉积组合，可见少量白云岩化的台缘礁+台缘滩沉积组合。研究成果为该区长兴组生物礁下一步的油气勘探提供了理论依据。
Abstract
Based on the observation of field outcrop profiles, cores and thin sections, combined with the data of logging, mud logging and seismic interpretation, the sedimentary assemblage type and distribution law of Changxing Formation on the east side of Kaijiang-Liangping trough in eastern Sichuan Basin are studied. The results show that the sedimentary assemblages of Changxing Formation can be divided into two types: reef sedimentary assemblages and non-reef sedimentary assemblages. Furthermore, the reef sedimentary assemblage can be divided into five types such as platform margin reef + platform margin beach, platform margin reef + intra-platform beach, platform margin reef + non-beach, intra-platform reef + intra-platform beach and intra-platform reef + non-beach. There are four types of non-reef assemblage: non-reef + platform margin beach, non-reef + intra-platform beach, platform margin beach + intra-platform beach and non-reef + non-beach. The Changxing Formation develops steep-slope type platform margin reefs and gentle slope type platform margin reefs, and the two reef types show different sedimentary assemblage law. The former develops platform margin reef + platform margin beach sedimentary assemblage. The latter is mainly platform margin reef + non-beach sedimentary assemblage, with a small amount of dolomitic platform reef + platform beach assemblage. The research results provide a theoretical basis for further oil and gas exploration of Changxing Formation reefs in this area.
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