Reservoir characteristics and development controlling factors of JZS Neo-Archean metamorphic buried hill oil pool in Bohai Sea

Abstract

JZS is the biggest buried hill oil pool in the Liaoxi uplift of Bohai Sea area,with dominated light grey gneiss and cataclasite.The laboratory test reveals that reservoir properties of JZS buried hill are reasonably good,but still very heterogeneous.Reservoirs in this area can be classified into 4 types with FMI and porosity log information:①network-dissolved fracture reservoir;②cataclasite reservoir;③dissolution fraction reservoir and ④micro-fracture tight reservoir.The Neo-Archean metamorphic buried hill reservoir in the JZS underwent diagenetic period→pre-buried→erosion-deformation→hypergenesis→post-buried period.The key controlling factors in JZS pool are Cenozoic palaeo-geomorphology and tectonic stress of Mesozoic and Cenozoic.The weathered eluvium is distributed in flat slopes of different highlands.Tectonic stress,weathering and dissolution during catagenesis,and organic acid dissolution during oil and gas infilling are the key to affect the evolution of metamorphic reservoir of the JZS oil pool.The evolutionary pattern of Neo-Archean metamorphic reservoir of the JZS oil pool can be applied to similar buried hills in the Bohai Sea area.