酒东盆地营尔凹陷油气生成和运移聚集

PETROLEUM GENERATION, MIGRATION AND ACCUMULATION IN YINGER DEPRESSION, THE EASTERN JIUQUAN BASIN

酒东盆地营尔凹陷存在下白垩统和中、下侏罗统２套生油层。其中，下白垩统中沟组下段有机质丰度类型最好，但尚处于低熟阶段；成熟的中、下侏罗统是极重要的生油层。营尔凹陷内，２套生油层生物标志物分布截然不同；下白垩统和中、下侏罗统中的原油是２类自生自储原油；３个异常高压流体带严格控制油气的纵向运移聚集；中、下侏罗统油气受近南北向断层和高压异常带的控制，长沙岭—下河清低隆起带及营参１井周围地区是最有利的勘探区，凹陷南部比北部更利于形成白垩系油气聚集，黑梁断层以东比以西地区好。本文将酒东盆地与酒西盆地作了比较分析，认为二者所处大地构造位置的差别造成了油气富集规律的差异。

There are two strata series of the Lower-middle Jurassic and the Lower Cretaceous potential source rock in Yinger depression, the eastern Jiuquan basin. Organic matter in the Lower Zhonggou formation, Lower Cretaceous, is the best in abundance and type and is low in maturity. Matured lower-middle Jurassic source rock is a very important potential source rock. Biomarkers in the two strata are quite different. Oils in Jurassic and Cretaceous reservoirs are two kinds of crude oils and derived respectively from its own potential source rock without long distance migration. Three abnormally overpressured zones occur in Yinger depression and strongly control the petroleum migration and accumulation. The difference in tectonic location results the different pattern of petroleum occurrence and accumulation between the eastern and the western Jiuquan basin. Oil and gas from the Lower-middle Jurassic source rocks are controlled by the faults trended in NNE and by the abnormally overpressured zones. The prospect of oil and gas exploration is better in the eastern region than in the western region divided by Heiliang fault, so that ChangshalingXiaheqing low uplift is the most potential area. The generation and accumulation of oil and gas from the Lower Cretaceous potential source rock are much favorable in the southern than in the northern in Yinger depression. This paper discusses the petroleum generation, migration and accumulation in Yinger depression, the eastern Jiuquan basin and makes a comparison with the western Jiuquan basin.