印度河盆地含油气系统特征与成藏模式

FEATURES OF PETROLUEM SYSTEM AND PATTERNS OF HYDROCARBON POOLING IN THE INDUS BASIN

印度河盆地是巴基斯坦最大的沉积盆地,油气资源丰富,油气主要聚集在白垩系—下第三系含油气系统中,以气为主。下白垩统Sembar组海相页岩是主要烃源岩,始新统Sui Main石灰岩和下白垩统下Goru组砂岩是盆地内的两套主要储集层,发育岩性、断块、断鼻和背斜等各类圈闭。油气成藏分为两期,早油晚气,早期形成了盆地南部巴丁地区的白垩纪被动裂谷断块油藏,晚期形成始新世石灰岩礁体岩性气藏。研究结果认为:盆地南部印度河三角洲入海处以及邻近海上区域和中西部褶皱带、前渊带是该区下一步寻找油气的主要目标靶区。

The Indus basin is the largest prolific petroliferous basin in Pakistan, with the gas-prone Cretaceous-Paleogene petroleum system as the major place for hydrocarbon accumulation. The Lower Cretaceous Sembar Formation marine shale is the main source rock, and the Eocene Sui Main limestone and Lower Cretaceous Lower Goru Formation sandstone are two major reservoirs in the basin, where various traps are developed, including lithologic trap, faulted block, fault nose and anticline. Two stages of hydrocarbon accumulation and pooling were recognized. In the first stage, the Cretaceous passive margin background rift faulted block oil reservoirs were formed in the southern part of the Indus basin. While in the second stage, the Eocene reefal limestone reservoirs were formed. The Indus delta area, adjacent offshore area and the middle-west fold belt and foredeep are the main targets of exploration in the future.