准噶尔盆地西北缘克百地区天然气成因与潜力分析

Analyses of the Genesis and Potential of Natural Gas in Kebai Area of Northwest Margin,Jungar Basin

通过准噶尔盆地西北缘克拉玛依—百口泉百地区天然气赋存特征、组成、类型与来源的分析,明确了佳木河组与石炭系烃源岩对气藏气的贡献,指出应加强烃源岩地质与地化特征、成气潜力的研究。天然气既有原油溶解气,也有较纯的气藏气。原油溶解气在二叠系和中生界油藏中均有分布,来源于风城组烃源岩,与原油同源同期运移聚集而成,属于油型气。气藏气主要分布在五八区的佳木河组和直接覆盖于佳木河组之上的上乌尔禾组,为佳木河组烃源岩高成熟阶段以独立气相运移聚集成藏的天然气,属于煤型气,佳木河组气源岩对佳木河组内部及其上覆紧邻地层气藏的分布有重要控制作用。石炭系烃源岩对深部位煤型气有贡献。已发现气藏的构造下倾部位或更深部位应该有一定的天然气勘探潜力,是下一步的重要勘探方向。

Based on the analysis of the natural gas occurrence features, component features, types and sources, this article shows the contribution of source rock of the Carboniferous and Jiamuhe Formation of the Lower Permian to the gas reservoir and points out that future research should be strengthened to the source rock geology, geochemistry characteristics, and gas-generating potential. To natural gas, there is not only dissolved gas in oil pools but also pure gas in gas pools. The dissolved gases distribute in both the Permian system and the Mesozoic, and were derived from the Fengcheng Formation source rocks. They migrate and accumulate with crude oil and are oil-type gases. The natural gases in gas pools distribute chiefly in the Jiamuhe Formation and the Upper Wuerhe Formation which overlays the Jiamuhe Formation in Wuba Area, were derived from the highly mature Jiamuhe Formation source rock and migrated, accumulated in gaseous phase, and they are coal type gas. The Jiamuhe Formation source rocks have an important controling role in gas pools in the Jiamuhe Formation and the strata overlying the Jiamuhe Formation. The Carboniferous source rocks have contribution to coal-type gas in depth. There is certain natural gas exploration potential in the structural downdip part of the discovered gas pools and deeper parts which will be the next main exploration target.