准噶尔盆地腹部深洼区超高压带分布规律

Distribution of Overpressure Zones in Deep Sub-Sag Area in Hinterland of Junggar Basin

准噶尔盆地腹部深洼区超高压顶界面与油气成藏有着密切联系。热作用导致的生烃增压作用以及与深部超高压系统所沟通的流体传递作用是形成超高的主要原因。将地层超高压分布规律应用于指导油气勘探,得到了钻井资料的证实,为加强该区的勘探工作提供了新方法。其深部烃类高压流体向高压封存箱顶界面突破并成藏,顶界面上部200m、下部100m区间为有利的成藏区间,封存箱外有利于原油成藏,封存箱内有利于天然气成藏。

The drilling data and the history of organic matter thermal evolution and overpressure evolution show that the deep sub-sag in hinterland of Junggar basin area is characterized by overpressure caused by thermal pressurization of hydrocarbon generation and the fluid transmission communicating with the deep overpressure system. And its top interface of overpressure is closely related to the hydrocarbon accumulation. Application of the distribution of stratigraphic overpressure to guidance of oil-gas exploration has been confirmed by the drilling information, providing a new method for strengthening the exploration in this area. The overpressure fluid in this deep sub-sag area flows toward the top interface of high-pressure compartment followed by breakthrough and accumulation, which may occur in range from 200 m obove the top interface and 100 m below it as a favorable interval for hydrocarbon accumulation. The outside of the compartment is favorable for crude oil accunmlation and the inside of it for natural gas accumulation.