克拉苏构造带克深区带超高压大气田成藏过程与特征

Accumulation process and characteristics of overpressured large gas field in Keshen belt of Kelasu tectonic zone

克拉苏构造带克深区带发育多个大气田,但形成和分布复杂。文章通过解剖克深2和大北1超高压大气田,分析了克深区带超高压大气田的形成过程,研究了克深区带超高压大气田的成藏特征。克深区带天然气δ13 C1分布在-2.83%^-4.07%之间,具有正碳同位素系列特征,天然气干燥系数都在96%以上,组分偏干。储层孔隙度主要分布在2.0%~9.0%之间,渗透率主要分布在(0.01~0.10)×10-3μm2之间,属于特低孔特低渗储层。断裂运移通道和圈闭形成于库车期,形成时间晚。总之克深区带具有晚期快速高效一次成藏的特征。

There are multiple overpressured large gas fields in Keshen belt of Kelasu tectonic zone, but the accumulation and the distribution of them are complicated. By analyzing Keshen 2 and Dabei 1 overpressured large gas fields, the accumulation process and accumulation characteristics of overpressured large gas fields in Keshen belt are researche＆ According to the test of component concentration and carbon isotope of the natu- ral gas samples, the value of o〈aC1 is from --2.83 % to --4. 07 ~, and it has the characteristics of b＇aa C1 ~aaCe^aCa. The aridity coefficient is over 96%, which indiates the natural gas is dry gas. The reservoir po- rosity is from 2.0% to 9.0%, and the reservoir permeability is from 0. 01×10^-3μm^2 to 0. 10 ×10^-3μm^2, which suggests that the reservoir porosity and permeability are low. The formation time of fracture migration channel and trap is at Kuqa stage, which is late. In general, the natural gas accumulation of Keshen belt has the characteristics of quick accumulation, efficient accumulation, late accumulation and once accumulation.