黄桥-句容地区二叠-三叠系烃源岩生烃历史及晚期成藏研究

黄桥-句容地区二叠-三叠系生储盖条件优越,是目前油气勘探的主要区域。烃源岩总体处于成熟和高成熟阶段,生烃模拟试验表明总有机碳含量在生烃过程中损失较少,可以作为评价较高成熟度烃源岩的有效指标。孤峰组、龙潭组和大隆组泥质烃源岩评价均为较好-好烃源岩,而以灰岩为主的栖霞组和青龙组烃源岩生烃能力则很差。高含量的矿物沥青基质和低值活化能的分布显示源岩处于正在生烃的阶段,活化能分布特征一定程度上反映了烃源岩的生烃过程,黄桥地区生烃温度范围跨度小,一进入主生烃期就能快速断键生烃,而句容地区则更倾向于早期、多期生烃的特点。源岩均普遍经历了多次生烃,喜山期的二次生烃相继进入生烃高峰阶段,生烃转化率主要取决于沉积埋藏史,演化程度慢的烃源岩保留生烃潜力,晚期继续生烃有利于强烈构造运动下的保存成藏。

Study on Permian-Triassic Hydrocarbon Generation Evaluation and History of Late Accumulation in Huangqiao-Jurong Area

In Permian and Triassic in Huangqiao-Jurong Area,the conditions of oil generation,reservoir and caprock were favorable,which was the area for oil exploration.The source rocks were at mature and highly mature stage,the simulation experiment of hydrocarbon generation showed that the loss of total organic carbon in the process of hydrocarbon generation was less,and it could be regarded as an effective index in the assessment of high source rocks.The argillaceous source rocks of the Gufeng,the Longtan and the Dalong Formations were all good-better source rocks,but the limestone of the Qixia and the Qiliong Formations was poor.The high content of mineral asphalt matrix and low activation energy indicated that the source rocks were at the stage of hydrocarbon generating,activation energy distribution reflected the process of hydrocarbon generation at certain extent,the temperature range of hydrocarbon generation was small in Huangqiao Area,and it quickly generated hydrocarbon when it went into the main generation time,in contrast,Jurong Area was better for early and multi-time hydrocarbon generation.The source rocks generally experienced many times of hydrocarbon generation,for the secondary hydrocarbon generation in Himalayan Period,the source rocks are at the peak of hydrocarbon generation,its conversion rate mainly depends on sedimentary burial history,the source rocks in slow evolution process retain more potential,and the continuous hydrocarbon generation at the late stage is beneficial for keeping the accumulation on intense tectonic movement.