试论吐哈盆地低断块油藏形成条件与分布规律

FORMING CONDITION AND DISTRIBUTION REGULARITY OF LOWER FAULTED BLOCK RESERVOIR IN TUHA BASIN

低断块油藏属于特殊类型的隐蔽油藏,其形成需要适当的条件。吐哈盆地低断块油藏在近期的油气勘探和储量增长中发挥了重要的作用。已找到的低断块油藏数量较多,但特点不一,形成条件各异。研究表明,油气的不断运移是低断块油藏形成的根本原因,而构造变动、异常高压含油气区的存在、长期生排烃、储层发育较差、油质重稠等都可以成为促使油气不断运移长期存在的因素。本文分析论证了低断块油藏特殊的形成条件及不同成因低断块油藏的分布规律。最后认为,在油气勘探过程中应重视对低断决油藏形成的可能性研究,胜北次凹周围低断块油藏勘探有较大的潜力。

Lower faulted block reservoir is a special type of subtle reservoir. It is formed at the proper condition. Recently, lower faulted block reservoir of Tuha Basin plays a very important role in oil - gas exploration and reserve increment. Many lower faulted block reservoirs have been formed, but the characteristics and forming conditions are different. The study shows that continuous migration of oil - gas is the main reason of forming lower faulted block' reservoir. Structure deformation, existence of abnormal high pressure petroliferous province, long - term generation, expulsion of hydrocarbon, poor reservoir development and viscosifing oil are the factors to impel continuous migration of oil - gas and it's long term existence. This paper analyzed and demonstrated a special forming condition of lower faulted block reservoir and distribution regularity of different genetic lower faulted block reservoir. Finally, it is considered that the exploration of lower faulted block reservoir around subdepression of Shenbei is with larger potentials.