【摘要】 通过大量露头、钻井岩心沉积相研究及地震相分析,将四川盆地及邻区二叠系划分为5个三级层序,编制了四川盆地及邻区三级层序地层格架下的二叠纪岩相古地理图,即层序PSQ1(栖霞组)、层序PSQ2-PSQ3(茅口组)、层序PSQ4(龙潭组/吴家坪组)及层序PSQ5(长兴组/大隆组)4个沉积期岩相古地理图,认为四川盆地及邻区二叠纪岩相古地理的演变主要受控于区域张裂构造背景及同沉积正断裂的活动,总体表现为张裂活动逐渐增强的趋势;中二叠世主要发育碳酸盐缓坡,晚二叠世演变为镶边台地;因中二叠世末期的峨眉地幔柱活动及其玄武岩喷发导致了康滇古陆的形成并成为川西南地区陆源碎屑沉积物源。通过岩相古地理图的编制,发现了一批台内礁滩及台内洼地,进一步明确了川北地区中缓坡相及台地边缘相的展布,对于四川盆地及邻区二叠系天然气勘探具有重要指导意义。结合主要烃源岩分布及成藏条件分析,提出环开江—梁平盆地上二叠统白云石化台缘礁滩、城口—鄂西盆地西南缘上二叠统白云石化台缘礁滩、川北地区中二叠统白云石化中缓坡礁滩、茅口组风化壳岩溶储层、上二叠统长兴组白云石化台内礁滩及中二叠统断裂热液白云岩储层是四川盆地二叠系碳酸盐岩储层的有利天然气勘探领域。更多还原

【Abstract】 Based on the sedimentological analysis of outcrops and drilling cores with seismic facies analysis,this study divided the Permian in Sichuan Basin and adjacent areas into five 3rd-order sequences,and prepared four maps of the Permian lithofacies paleogeography of Sichuan Basin and adjacent areas in the 3rd-order sequence stratigraphic framework,i.e.,PSQ1(Guadalupian or Middle Permian Qixia Formation),PSQ2-PSQ3(Guadalupian Maokou Formation),PSQ4(Longtan/Wujiaping Formation,Wuchiapingian Stage of Lopingian or Upper Permian),and PSQ5(Changxing/Dalong Formation,Changhsingian Stage of Lopingian).These showed that the evolution of Permian lithofacies paleogeography in Sichuan Basin and adjacent areas was mainly controlled by the background of regional rifting tectonics and the activities of syndepositional normal faults with an overall increasing trend in the rifting activity.Carbonate ramps mainly occurred in the Guadalupian and evolved into rimmed platform in the Lopingian.The Emei mantle plume activity and basalt eruptions in the end of Guadalupian led to the formation of Kangdian oldland,which became the provenance of terrigenous clastic sediments in the southwestern Sichuan.Through the compilation of lithofacies paleogeography maps,a series of intra-platform reefs and shoals as well as intra-platform depressions was discovered.It further clarified the distribution of middle ramp facies and platform margin facies in the northern Sichuan Basin,and provided guidance for exploration of natural gas in the Permian in Sichuan Basin and adjacent areas.Based on the distribution of main hydrocarbon source rocks and the accumulation conditions,it was proposed that the favorable natural gas exploration zones of Permian carbonate reservoirs in Sichuan Basin included:(1) the dolomitized platform-margin reefs and shoals of the Lopingian around Kaijiang-Liangping basin facies;(2) the dolomitized platform margin reefs and shoals of the Lopingian along the southwest margin of Chengkou-E’xi basin facies;(3) the dolomitized middle-ramp reefs and shoals of the Guadalupian in the northern Sichuan Basin;(4) the weathering crust karst reservoirs of Maokou Formation;(5) the dolomitized intra-platform reefs and shoals of the Lopingian in Changxing Formation;and(6) the fractured hydrothermal dolomite reservoirs of the Guadalupian.更多还原