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通过大量钻井岩性统计、岩心观察、露头沉积相研究与地震相分析,结合板块构造演化等区域地质资料,以体系域为单元编制了4张三级层序地层格架下的四川盆地及邻区早三叠世印度期岩相古地理图,明确了开江—梁平盆地相主要发育于飞仙关组一段及二段沉积期,在飞仙关组三段沉积期已演化为台内洼地,以及不同时期盆地内部鲕粒滩体的展布与迁移特征,且在盆地周缘绵竹、湖北利川等露头发现了台地边缘鲕粒滩,为四川盆地飞仙关组鲕滩气藏的勘探提供依据。四川盆地飞仙关组各体系域都有鲕粒滩体分布,其中层序TSQ1高位体系域(相当于飞仙关组二段)及层序TSQ2海侵体系域(相当于飞仙关组三段)沉积期鲕滩规模最大,也是主要产气层段,滩体展布具有由台地内部不断向盆地相区迁移的特征。层序TSQ1海侵体系域(相当于飞仙关组一段)沉积期,开江—梁平盆地相两侧的镶边台地边缘鲕粒滩(坝)规模不大,鲕粒滩体主要分布于台内古地貌高地以及滨岸地带;层序TSQ1高位体系域沉积期,鲕粒滩(坝)沿开江—梁平盆地相两侧及城口—鄂西盆地相西南缘台地边缘集中分布;层序TSQ2海侵体系域沉积期,川北、川东地区发育鲕粒滩体且规模较大;层序TSQ2高位体系域(相当于飞仙关组四段)沉积期,滩体分布较少,主要为局限台地和蒸发台地沉积。四川盆地下三叠统飞仙关组天然气有利勘探区带主要是环开江—梁平盆地白云石化台缘滩相、城口—鄂西盆地西南缘白云石化台缘滩相以及溶蚀的台内滩相。
Based on a large number of drilling lithology statistics, core observation, outcrop sedimentary facies analysis and seismic facies analysis, combined with the regional geological data of plate tectonics and evolution, four Sichuan basin and adjacent The lithofacies palaeogeographic maps of the Early Triassic Indian period reveal that the Kaijiang-Liangping basin mainly developed in the first and second periods of the Feixianguan Formation. During the sedimentary period of the third member of Feixianguan Formation, , As well as the distribution and migration of oolitic beach in different periods of the basin. Oolitic beach on the edge of platform was found on the outcrop of Mianzhu and Lichuan in the basin, which provided the basis for the exploration of the oolitic beach gas reservoirs in Feixianguan Formation in Sichuan Basin . The Feixianguan Formation of Sichuan Basin has oolitic beach body distribution in all the systems, of which the sequence TSQ1 highstand system tract (equivalent to the second member of Feixianguan Formation) and the sequence TSQ2 transgressive system tract (equivalent to Feixianguan Formation III During the sedimentary period, the oolitic beach is the largest in size and also the major gas-producing interval. The distribution of the beach body has the characteristics of continuous migration from the interior of the platform to the facies of the basin. In the sedimentary period of the sequence TSQ1 transgressive system tract (equivalent to the first member of Feixianguan Formation), the oolitic beach (dam) at the edge of the margin of the Kaiping-Liangping Basin is not large in scale and the oolitic beach body is mainly distributed in Taiwan In the depositional period of the TSQ1 highstand system tract, the oolitic beach (dam) is concentrated along the margin of the platform margin of the Kaixiang-Liangping basin and the southwestern margin of the western margin of the Chengkou-western Hubei basin. Sequence In the depositional period of the TSQ2 transgressive system tract, the oolitic beach body developed in the northern Sichuan and eastern Sichuan was larger in scale. In the sedimentary period of the TSQ2 highstand system tract (equivalent to the fourth section of Feixianguan Formation), the distribution of the beach body was less Deposition and evaporation platform deposition. The favorable gas exploration zones in Feixianguan Formation of the Lower Triassic in the Sichuan Basin are mainly dominated by the Wanjianjiang-Dolomitization platform margin facies in the Liangping Basin, the dolomitization margin margin in the southwestern margin of the Chengkou-Western Hubei basin, phase.