吐哈盆地天然气聚集模式及致密气藏有利勘探方向

Natural Gas Accumulation Model and the Favorable Exploration Direction for Tight Sandstone Gas Pool in Tuha Basin

吐哈盆地天然气资源十分丰富。在分析天然气成因、分布和成藏模式的基础上,将该盆地天然气成因类型划分为3种。Ⅰ型天然气主要分布于三间房组和三叠系中,Ⅱ型天然气主要分布在中侏罗统中,Ⅲ型天然气除三叠系外均有分布,其中,致密气藏成因类型主要为Ⅲ型;天然气成藏模式可概括为侧向分异、垂向分异、近源分异及混合聚集4种类型,其中,近源分异是致密气藏主要成藏模式,在吐哈盆地东部邻近凹陷具有较大的勘探潜力。

Tuha basin is very rich in natural gas resource. This paper presents the classification of the gas resources in terms of gas origin, distribution and accumulation pattern into three types： Type-Ⅰ gas is mainly distributed in the Sanjianfang formation and Triassic strata; Type-Ⅱ is in the Middle Jurassic; Type-III is widespread except for the Triassic, in which tight sandstone gas reservoir origin type belongs to the Type-Ⅲ. The natural gas accumulation can be divided into four models, such as lateral differentiation, vertical differentiation, near-source differentiation and hybrid accumulation ones, among which near-source differentiation is the main gas accumulation model and pos-sesses greater exploration potential in adjacent sags of the eastern Tuha basin.