陕甘宁盆地中部大气田成藏条件分析

陕甘宁盆地大气田的发现既是天然气勘探上的突破又是对盆地天然气成藏条件认识上的转折，认识到受风化侵蚀的古台地才是盆地天然气勘探的目标。气田主要边界受夹持古台地的沟槽发育的控制：沟槽中早期充填石炭系煤系地层并成为煤成气向古台地溶孔运移的通道，燕山运功后，台地东侧的沟槽抬升成为天然气向东运移的天然屏障。文中论述了中部大气田两套气源岩、岩相与岩溶、风化壳地貌及靖边气田成藏、形成高产区的基本地质条件。最后对勘探远景作出评价。

A Study on the Conditions of Forming Reservoir at the Center of the Great Gas Field in Shanganning Basin

The finding of the great gas field is a breakthrough in gas exploration and a turn point in understanding the condition of forming gas reservoir in Shanganning Basin. The weathering old platform is the aim of gas exploration. The gas field (reservoir)is mainly controlled by canal growth of old platform gripped by boundaries. The canals were filled by Carboniferous coal measure strata and became channals through which coal-formed gas migrated to solutional void of old plat form in early stage. After Yanshan Motion,the canals in eastern plat form were raised and become natural barrier to prevent gas from migrating to east. This paper discusses the primary geological conditions of two sets of gas source rock,petrofacies and karst,ground feature of weathering,crust and forming reservoir of Yanbian Gas Field,getting high production at the center of the gas field. Exploration prospectives is evaluated at last.