Controlling Factors of Triassic Oil and Gas Accumulation in Wuerhe-Xiazijie Area, NW Junggar Basin
准噶尔盆地乌夏地区三叠系油气成藏控制因素分析

Triassic oil sources of the Wuerhe-Xiazijie fault belt are abundant, but the accumulation is controlled by composite factors. This paper analyzes the controlling factors: (1) The fault occurrence in different eras have different effects on the oil and gas accumulation; (2) Unconformity surfaces are usually major hydrocarbon migration channels and the belts of hydrocarbon accumulation; (3) The Triassic fan delta faceis and the alluvial fan facies are favorable reservoir blocks in this region; and (4) The Triassic oil reservoirs in the Wuerhe\|Xiazijie area possess multiple reservoir\|seal assemblages, and the Karamay Formation and the Baijiantan Formation are major regional cap rocks. Comprehensive analysis shows that Triassic oil reservoirs are mainly lithologic and stratigraphic oil reservoirs, which occurred in the background of nose\|uplift structure. The key reservoir\|forming rule in this area is that lithologic and stratigraphic oil reservoirs are controlled by structure background.