北极含油气域大油气田形成条件和分布规律

Formation and Distribution of Giant Oil and Gas Fields in Arctic Petroliferous Domain

北极含油气域包括了北极圈以北的广大区域,具有非常丰富油气资源。根据北极地区的构造演化,结合区内地层特征、盆地分布及其发育特征,研究区内油气地质条件,通过剖析研究区大油气田的成藏要素和作用,并结合含油气系统的思想,探讨大油气田的形成条件和分布规律。研究表明,北极地区的构造演化控制了北极含油气域的含油气盆地的形成和演化。其中巨型裂谷的发育、联合古陆的形成与裂解以及北大西洋的形成使北极含油气域具备了优越的油气地质条件。因此,中生界是区内含油气盆地烃源岩、储层和盖层发育的主要层位,其次是新生界。区内主要以大气田为主,大油气田的圈闭类型以构造圈闭为主,油气生成大多开始于侏罗纪,运移高峰则大多发生在白垩纪以后。在大油气田数量和可采储量上,区内白垩系是大油气田分布最多的地层,其次为侏罗系。研究区勘探程度很低,仍有大量的油气资源待开发或未开发,但由于不确定性因素多,区内油气资源的勘探开发风险大,因此对大油气田的分布规律需进一步的研究。

Rich in hydrocarbon resources, the Arctic petroliferous domain covers an extensive area in the north Arctic Circle. Based on the tectonic evolution of Arctic region and combined with the stratigrahic characteristics as well as the distribution and development characteristics of basins, the study was made of hydrocarbon geologic conditions in the area. With the elements and process of giant oil and gas fields in this domain analyzed, this paper uses a series of oil and gas theories to study formation and distribution of giant oil and gas fields. The study indicated that the tectonic evolution of the Arctic region controlled formation and development of oil and gas basins in this domain. Moreover, development of giant rifts, buildup and breakup of Pangea and formation of the North Atlantic endowed the domain with the superior hydrocarbon geological conditions. Therefore, Mesozoic is the most important horizon developed as source rock, reservoir and cap rock in the area, while the second important horizon is Cenozoic. The domain includes giant gas fields. The type of trap is mainly structural one. Oiland gas were accumulated mainly in the Jurassic Period but the migration peak basically took place after the Cretaceous Period. Giant oil and gas fields are mostly distributed in the Cretaceous System in terms of quantity and recoverable reserves, and next is the Jurassic System. The domain is very low in exploration degree. There is still a large of resources in the region that is to be developed or remain undeveloped. However, the risk for oil and gas exploration and development in the region is high because of many uncertainties. It is necessary to make a further study of the distribution law of giant oil and gas fields in the domain.