Study On Lithologic Characteristics And Evolution Of Sealing Properties Of Borjianghaizi Fault Zone

As one of the most important pathways of hydrocarbon migration, the sealing properties of faults played a key role in the processes of hydrocarbon migration and accumulation. The study on evolution of fault sealing properties is one of the frontiers and hot topics of geosciences in the present age. Based on evolution of fault sealing properties analyzing in faults developed region, the processes of hydrocarbon generation, migration and accumulation can be reconstructed, thus some key knowledge on oil pool forming and distributing can be gained. Additionally, it is also helpful to hydrocarbon exploration.Hangjinqi, in the Northern Ordos basin, is selected as the major research area in this paper. The research on evolution of lateral sealing properties of Borjianghaizi fault zone has been explored to carry out, in order to clarify the lateral sealing properties of Borjianghaizi fault zone in 6 geological ages which from middle Jurassic till now, thus point out the directions of exploration and development of hydrocarbon. Therefore the systematical research on distributive features, formation, evolution and sealing properties in present age of three major faults in Borjianghaizi fault zone has been carried out, after the broad research,collecting and analyzing a lot of firsthand material and computer numerical simulation. And the lateral sealing properties of Borjianghaizi fault zone in 6 geological ages which from middle Jurassic till now has been simulated and reconstructed by using computer numerical simulation, based on reconstruction of basin burial history.The Borjianghaizi fault zone is considered as unsealing in present age and worked as migration pathway of hydrocarbon by analyzing the disposition of rock types of both fault blocks, Shale Gouge Ratio (SGR) and chemical characteristics of formation water within both fault blocks of Borjianghaizi fault zone.The distributive features and burial characteristics of both fault blocks of Borjianghaizi fault zone in key geological ages when before yanan formation deposited, before zhiluo formation deposited, before anding formation deposited, before Cretaceous System deposited, before Cretaceous System erosion and present has been reconstructed through reconstructing basin burial history.The sealing properties of three major faults in 6 key geological ages has been analyzed by using methods which are used in researching sealing properties in present age, such as Shale Gouge Ratio (SGR) analyzing. After study, the three major faults are considered as unsealing in those 6 geological ages.Therefore, the conclusion is achieved that the Borjianghaizi fault zone is unsealing since the time when the petroleum began to generate and migrate. Thus, the petroleum generated at the south of Borjianghaizi fault zone could migrate to the north of the Borjianghaizi fault zone and accumulate at the possible place.