以喉道为参数的致密砂岩气储层评价方法--以库车坳陷迪北地区致密砂岩气为例

致密砂岩气作为一种非常规天然气在我国呈现出快速发展的趋势，然而目前致密砂岩气储层的评价仍然沿用常规油气藏储层评价的方法。事实证明常规油气藏储层评价的方法明显不适用于致密砂岩气。本文通过对比常规气藏与致密砂岩气的发育特点，以库车坳陷迪北地区致密砂岩气为研究对象，开展多手段的储层孔喉微观分析，认为喉道半径是控制致密砂岩气运聚与富集的关键因素之一。并通过改进的Windland方程以进汞饱和度35%时所对应的喉道半径（R₃₅）为主要参数，建立了适合于研究区的致密砂岩气储层评价方法。评价结果显示，R₃₅=0.17 μm是区分库车坳陷迪北地区致密气有效储层与无效储层的界线；同时依据R₃₅的大小可进一步将有效储层划分出Ⅰ类、Ⅱ类和Ⅲ类储层。

Using Throat Parametre to Assess Tight Sandstone Gas Reservoir: A case study of Dibei tight sandstone gas in the east of Kuqa Depression

Tight sandstone gas as a kind of unconventional natural gas which showed a trend of rapid exploration development in China. In order to assess the tight sandstone gas reservoir, however, we still continue to use conventional sandstone reservoir assessing parameters and method. The fact proved that the conventional method used for the assessment of tight sandstone gas is obvious inadaptability. In this paper, by comparing the characteristics and forming mechanism between conventional gas reservoir and tight sandstone gas, we conclude that the throat radius and the gas pressure are the critical factors of tight sandstone migration and enrichment. Using the improvement Windland equation with R₃₅ parameter which is on behalf of the throat radius when mercury saturation arrives 35%, established a preferable assessing methods for tight sandstone gas reservoir in Dibei aera. Assessment results show that the R₃₅=0.17 μm is the boundary of effective reservoir and invalid reservoir;At the same time, on the basis of the R₃₅ size, the effective reservoir can be further divided intoⅠ, Ⅱ and Ⅲ class.