Hydrocarbon accumulation pattern of Kayindike region in southern Junggar Basin

Based on the static elements for reservoir formation, taking the dynamic evolution process of the elements as the main line, the comparison of biomarkers and the analyses of source rock thermal evolutions, fluid inclusions and typical reservoirs were made to study the hydrocarbon source and accumulation process in the Ka-yindike region in the southern Junggar Basin. A hydrocarbon accumulation model was established to guide hydrocarbon exploration. Crude oils in the Kayindike region were classified into 3 types, respectively, from the Jura-ssic coal series, the Paleogene lacustrine mudstones and the two mixed, and the Jurassic coal series were more contributive. There were 2 major charging periods, about 10-8 and 2 Ma, respectively, and the ancient reservoirs charged in the 1st period adjusted during the 2nd period. The permeable sand series in the Kayindike region were controlled by the northern source materials, and were poorly connected with the south. Hydrocarbon migrated mainly along regional unconformities, and faults played important roles in communicating deep source rocks and ancient reservoirs. Controlled by faults and anticlines, the reservoirs were mainly fault-controlled and squeeze anticline type. The main controlling factor for hydrocarbon accumulation was the faults communicating source rocks. The hydrocarbon accumulation model was featured by mixed sources, vertical migration and 2 accumulation periods, among which the 2nd period was the major one.