蒙古国塔木察格盆地南贝尔凹陷的东部次凹有较好的油气勘探前景。本文介绍了烃源岩的分布，指出南屯组有机质丰度普遍较高，铜钵庙组有机质丰度随地而异。有机质类型以II1型和II2型为主，埋深1600 m为生油门限，铜钵庙组和南屯组烃源岩的有机质处于成熟阶段，大磨拐河组烃源岩刚进入生排烃阶段。南屯组下部的低位体系域是最有利的目的层系，II油组是主力含油气层段。南屯组储层的孔隙类型主要为原生孔和溶蚀孔，总体属低孔低渗型储层，储层和孔隙度的平面分布受控陷断层、物源区和埋深等因素控制。
The East Sub-Sag of South Buir Sag, Tamtsag Basin in Mongolia has a good prospect for oil-gas ex-ploration. The paper introduced the distribution of the Lower Cretaceous source rocks and pointed out that the abundance of organic materials in the Nantun Formation is relatively high, while the abundance of organic materials in the Tongbomiao Formation is changed from place to place. The types of organic materials in the East Sub-Sag take II1 and II2 as the dominant ones. The oil-producing threshold is in the burial depth of 1600 m, so the organic materials of source rocks in the Tongbomiao and Nantun Formations are in the mature stage, and the source rocks in the Damoguaihe Formation are just to enter the stage of hydrocarbon’s producing and discharging. The lower system tract of the No.1 Member, Nantun Formation should be the most interesting target strata, and the II Oil Group a main oil-bearing layer. The majority of pore’s types consist of primary pore and dissolution pore. Generally speaking, the reservoir of the Nantun Formation belongs to a type of low-porosity and low-permeability. The planar distribution of reservoirs and porosities might be related to the contemporaneous depression-controlling faults, source regions and buried depth of the sandstone bodies.
