The main controlling factors of a hydrocarbon accumulation model of the upper Paleozoic in the Jurong area of the Lower Yangtze region were discussed. Regional geology and hydrocarbon accumulation processes in some key exploration wells were studied using the relationship between oil and gas accumulation elements and the spatial?temporal distribution of the marine strata in the Upper Paleozoic in the study area. The results showed that:(1) The Upper Paleozoic Longtan and Qinglong formations provided source rocks, carbonate fractures on the Indosinian unconformity surface and the tight sandstones in the Longtan Formation worked as reservoirs, and the shale in the Gecun and Pukou formations functioned as cap rocks. The tectonic and accumulation histories obtained from typical exploration wells indicated that traps were formed and adjusted continuously due to multiple tectonic activities. The tectonic uplift during the late Himalayan period destroyed hydrocarbon reservoirs, leading to a great loss of oil and gas in Jurong area. (2) Three classes of oil and gas reservoirs developed, including the secondary residual, primary preservation and the late reconstruction types. Preservation conditions for oil and gas were the key factors for hydrocarbon accumulation in Jurong area. The Qinglong Formation experienced erosion and leaching during the Indosinian and Yanshanian periods, forming a large number of caves and cracks, which controlled the late reconstruction of fractured?vuggy carbonate reservoirs on the unconformity surface.%基于下扬子句容地区海相上古生界油气成藏要素与时空配置关系,通过区域地质分析及重点探井成藏过程的研究,探讨了研究区上古生界可能的油气成藏模式及油气成藏主控因素.研究认为:(1)下扬子句容地区上古生界存在以龙潭组、青龙组为源,以印支期不整合面碳酸盐岩缝洞、龙潭组致密砂岩为储层,葛村组、浦口组泥岩为盖层的生储盖组合.典型钻井构造史与成藏史表明,多期的构造运动使得圈闭处在不断形成和调整的过程中,喜马拉雅晚期的构造抬升作用对油气藏破坏十分明显,长期抬升造成了句容地区油气大量散失.(2)典型油藏解剖表明,研究区主要发育次生残留型、原生保存型及晚期重建型3种油气藏.油气的保存条件是句容地区3种类型油气成藏的关键.另外,青龙组在印支期、燕山期遭受剥蚀、淋滤,形成大量的溶洞、裂缝,是控制不整合面碳酸盐岩缝洞型油藏油气(晚期重建型)分布的另一个重要因素.
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