川东南地区须家河组天然气远源成藏模式

摘要

探讨川东南地区须家河组致密砂岩油气成藏条件与主要成藏模式，为进一步深化该领域的勘探提供参考。通过对川东南地区须家河组烃源、储层、盖层和圈闭条件等成藏要素的分析及以官渡须四段气藏为代表的典型气藏解剖，表明川东南地区须家河组气藏主要为“深生浅聚”型的远源成藏模式，气藏具有“多期运移聚集，断层裂缝联合输导，喜马拉雅期调整成藏”的特点。具备与下部海相烃源岩沟通的断层输导体是川东南须家河组远源成藏的关键因素。良好的砂岩储集体匹配发育的裂缝系统，是该区天然气富集高产的保证。川东南地区须家河组油气勘探方向应以“位于心滩、边滩等有利沉积相带内，伴随发育烃源断层形成的致密砂岩构造-岩性复合圈闭及构造圈闭”为主。%This paper discusses the forming conditions of oil and gas accumulation and the main accumulation model of the tight sandstone in Upper Triassic Xujiahe Formation of Southeast Sichuan in order to provide references for deepening the oil and gas exploration of the area.Based on the analysis of the factors of hydrocarbon accumulation,such as hydrocarbon source,reservoirs,cap rocks and traps of Xujiahe Formation,and the dissection of the typical gas pool represented by that in the 4th member of Xujiahe Formation in Guandu,it is found that the distal gas accumulation is the main accumulation model of Xujiahe Formation in Southeast Sichuan,and the fault fractures formed in Himalayan motion period are the channels of gas migration.The fault fissure conductive bodies cutting through the lower marine hydrocarbon source rocks become the key factors of the distal gas accumulation of Xujiahe Formation in Southeast Sichuan,and the favorable sandstone reservoirs and the developed fracture system stand sure for high productivity of gas.Finally,the main oil and gas exploration direction in Xuj iahe Formation of the area is to seek for the tectonic-lithologic combination trap and structural trap of the tight sandstone with favorable hydrocarbon source rock fractures located in the advantageous diara and point bar facies zone.