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基于对四川盆地上三叠统油气地质背景、成藏条件、运聚机理和分布规律的综合分析,提出了须家河组天然气聚集是发育于含煤地层的“连续型”气藏、层状岩性大气区,煤系烃源岩大面积层状蒸发式排烃,盆缘造山带“幕式”冲断挤压背景下多物源间断性快速注入形成大平原、小前缘的粗粒三角洲体系,平缓构造背景下低—特低渗透砂体内天然气运聚过程中浮力作用受限,达西和非达西渗流机制并存,形成气-水-干层共生的混相成藏系统等新认识。对成岩相进行了定量分类,确定了8种成岩亚相、20种成岩微相。运用压实率、胶结率、溶蚀率等指标定量表征成岩相,运用Ro值、地层水参数等定量剖析了成岩相的成因。“连续型”气藏形成的大气区主要发育于中国中部构造稳定的大型陆相坳陷、前陆平缓斜坡或海陆交互相环境,具有大面积层状展布、无明显的圈闭界限和直接盖层、连片砂体弥漫式含气并有“甜点”、资源规模大、储量丰度较低和开采技术要求高的特点。
Based on the comprehensive analysis of the Upper Triassic hydrocarbon-gas geologic background, reservoir forming conditions, transport and accumulation mechanism and distribution in the Sichuan Basin, it is proposed that the natural gas accumulation in the Xujiahe Formation is a “continuous” gas reservoir developed in coal-bearing strata, Stratified lithologic atmosphere, large-scale stratified evaporative hydrocarbon expulsion of coal-based hydrocarbon source rocks and rapid injection of multiple sources into the Great Plains under the background of the “ In the coarse-grained deltaic system, buoyancy is limited during natural gas migration and accumulation in low-ultra-low permeability sand bodies with gentle tectonic setting. Darcy and non-Darcy percolation mechanisms coexist to form a mixed phase of gas-water-dry-layer formation System and other new understanding. Quantitative classification of diagenetic facies, identified eight kinds of diagenetic subfacies, 20 kinds of diagenetic microfacies. The diagenetic facies were quantitatively characterized by compaction rate, cementing rate and dissolution rate. The origin of diagenetic facies was quantitatively analyzed by Ro value and formation water parameters. The atmospheric zone formed by the ”continuous“ gas reservoirs mainly develops in the structurally stable large-scale continental depression in central China, the gentle slope of the foreland or the land-sea interphase environment with large-area stratified distribution with no obvious confinement boundaries And direct capping, contiguous sand bodies with diffuse gas and ”sweet", large scale of resources, low abundance reserves and high requirements of mining technology.