Late-stage Hydrocarbon Accumulation in the Bozhong Depression of the Bohai Bay Basin as Controlled b

• 作 者: Gong Zaisheng ZHANG Gongcheng CAI Dongsheng HE Shibin
• 机 构: China National Offshore Oil Corporation,Beijing 100026;Research Center of China National Offshore Oi
• 出 处: 地质学报(英文版)
• 发表日期: 2004年3期
• 关键词: Bozhong depression neotectonism late-stage hydrocarbon accumulation Tanlu fault

Neotectonism occurred intensively in the Bozhong depression in the Bohai Bay Basin, which was reflected vertically by dramatic subsidence and a number of uplifts and laterally by notable fault movements. This particularity has resulted in the special petroleum geological conditions of the Bozhong depression which are different from those of adjacent lands. For example, the source rocks of the Shahejie Formation were overpressured and hydrocarbon generation occurred in the late stage; the Dongying Formation was deeply buried below the hydrocarbon-generating threshold,therefore there were sufficient oil sources. The rapid subsidence led to starved sedimentation of the Guantao Formation fine sandstone and the regional Minghuazhen Formation lacustrine shale, which formed the Neogene regional reservoircaprock association. The active faults formed in the neotectonism became passages for oil to migrate from the Paleogene to Neogene. The traps formed by late fault activity and accompanied anticlines provided spaces for the formation of reservoirs. All the above factors match well with one another in the Bozhong depression, providing favorable conditions for the formation of a series of large oilfields in the region