MIGRATION AND ACCUMULATION LAWS OF JURASSIC HYDROCARONS UNDER THE COMPLEX STRUCTURAL ENVIRONMENT OF BAIJIAHAI UPLIFT JUNGGAR BASIN CHINA

Research on the migration and enrichment of hydrocarbons under the background of complex geological environment is a hot spot in the field of energy geology. In this paper, the migration and accumulation characteristics of Jurassic hydrocarbons in Baijiahai Uplift in Junggar Basin, China were systematically analyzed based on geological, geochemical and seismic data. Furthermore, the main controlling factors of oil and gas enrichment were summarized, and the oil and gas enrichment model was established. Studies have shown that the Jurassic hydrocarbon migration and accumulation patterns of Baijiahai Uplift can be divided into two major systems. One is a close-range oil and gas migration and accumulation mode from P2 source rock in Dongdao Haizi Sag. This type of hydrocarbon migration and accumulation system has the characteristics of "vertical supply of hydrocarbons, two-stage charging, vertical transport of faults and lateral transport of sand bodies supplemented by traps near the fault zone". The enrichment of hydrocarbons is mainly controlled by faults, sand bodies and caprocks. The other one is the long-distance hydrocarbon migration and accumulation mode for hydrocarbon supply from J1 source rock in Fukang Sag. The hydrocarbon migration and accumulation of this system have the characteristics of "lateral supply of hydrocarbons, primary charging, lateral transportation of sand bodies, vertical transportation of faults, and accumulation of hydrocarbons in traps near structural ridges". Therefore, hydrocarbon accumulation is mainly controlled by sand bodies and structural ridges. In the composite part of the fault zone and structural ridge in the northern Baijiahai bulge, the two major hydrocarbon migration and accumulation systems converge, and hydrocarbons are most enriched. Finally, the hydrocarbon enrichment mode was established.