The Research On Hydrocarbon Enrichment Regularity Of Chang8Oil Bearing Formation In Jiyuan Area

This paper investigates the Chang8member in Triassic Yanchang Formation of Jiyuan area, Ordos basin. In the learning of sedimentary cycle, the bed of Chang8is subdivided into Chang82and Chang8i in ascending order, according to the obvious characteristic of log and that one’s property of rock (the sedimentary cycle and the marker bed of Kl).Analysis the types of sedimentary facies and sedimentary microfaceies according to the combination of logging curves and sign system of sedimentary facies. It is considered that the subfacies of Chang8oil bearing Formation were mostly consists of delta plain and delta front.On this basis, studying on the characteristics of Chang8reservoir with the combining macroscopical study and microcosmical study. Evaluation of Chang8reservoir according to the pore structure parameter, formation lithology and physical property as well as capillary pressure characteristics.The paper discussed the factors of reservoir from the generation, storage, capping, migration, trapping and preservation of petroleum in the basin,it was considered that the oil-gas reservoir type in this area is lithological reservoir. Based on the reservoir characteristics and fluid property of Chang8oil bearing formation, it was considered that the oil and gas migration and accumulation patterns of the "injection migration" with Chang8reservoir, the overpressure of Chang7is the main driving force for the hydrocarbon migration and accumulation.The hydrocarbon enrichment regularity of Chang8oil bearing formation is mainly integrated controlled by the effective allocation of lithologic trap and tectonic condition, nearing source sag, a good resoure reservoir cap rock combination, the favorable sedimentary facies belt and the high-permeability reservoir factors in the research area.Under the guidance of the law, for the specific geological conditions of the study area, favorable areas of Chang8oil bearing Formation are predicted with characteristics of reservoir which have been developed.