塔里木盆地孔雀河斜坡成藏主控因素探讨

Main controlling factors for petroleum accumulation in Kongquehe slope,Tarim Basin

孔雀河斜坡油气形成与加里东晚期古构造密切相关,古构造背景是成藏的必要条件,烃源岩生排烃高峰与圈闭形成的时空配置关系是孔雀河斜坡成藏的主要控制因素,具有古构造背景的圈闭为有利的勘探目标。该区主力烃源岩为寒武系-中下奥陶统,其在加里东中晚期演化达到成熟—过成熟,在后期的演化中不具有二次生烃能力,圈闭形成期主要为加里东晚期及燕山中期。成藏期次分析、勘探实践、原油裂解气形成条件等进一步支持孔雀河斜坡所发现的油气可能为早期原生油气藏。

Petroleum generation in the Kongquehe slope is closely related with paleostructure during the late Caledo- nian Movement. Paleostructural background is the key for accumulation. The space-time matching relationship between the peak of hydrocarbon expulsion of source rock and the trap formation works as the main controlling factor. The traps with paleostructural background are favorable exploration targets. The main source rocks from Cambrian and Middle-Lower Ordovician become mature and over-mature during the middle and late Caledonian stage, and do not generate hydrocarbon during the late period. Traps are formed during the late Caledonian and the middle Yanshanian stages. The studies of accumulation stage, exploration practice and conditions of crude oil cracked gas prove that the discovered oil and gas in the Kongquehe slope may be early primary petroleum accumulations.