辽西-冀北地区中-新元古界储层油气特征及运聚史分析

Study on reservoir fluid and the history of hydrocarbon migration and accumulation in the Middle-Upper Proterozoic System in the West Liaoning-North Hebei area

利用显微观察、包裹体岩相学等手段,研究了辽西-冀北地区中-新元古界储集层有机质的赋存状态、油气包裹体特征和期次。结合区域构造演化史,初步分析了油气的运移和聚集历史。研究表明,辽西-冀北坳陷中-新元古界储集层同时存在液体原油、稠油和固体沥青三种有机质,储层的各种成岩矿物内发育大量的、类型各异的油气包裹体,表明它有多期油气的活动过程。据包裹体的产状和光学特征判定,储层早期活动的油气为成熟度较低的重、稠油,以自生自储为主;中-晚期活动的油气成熟度较高,成藏规模较大,油气主要沿构造运动的裂隙运移。

This paper applies microscopy observation and fluid inclusion petrography analytical methods for the first time in China to the research on the occurrence of organic matter, characteristic of petroleum inclusion and its developmental stages in reservoir of the Middle-Upper Proterozoic in West Liaoning-North Hebei. According to the above mentioned study, combining with structure evolution history, the history of hydrocarbon migration and accu- mulation has been carried out a preliminary analysis. It is shown that there are three types of organic matter, including liquid petroleum, heavy oil and solid bitumen in reservoir of the Middle-Upper Proterozoic in the West Liaoning-North Hebei area. All kinds of organic inclusions in different diagenesis mineral of reservoir indicated that the reservoir experienced multistage oil and gas charging. According to the occurrence and the optical character, it can be concluded that the hydrocarbon formed early is heavy oil with low maturity, a large proportion of oil is self-storage. In contrast, the larger reservoir hydrocarbon formed late is high maturity oil, activity of which on a large scale shown by migration of hydrocarbon through crannies is related to tectogenesis.