库拜煤田煤系致密砂岩储层气测显示特征与含气量估算

Logging Shows Characteristics and Content Estimation of Tight Sandstone Gas of Coal Measures in Kubai Coalfield

为快速、准确评价库拜煤田煤系致密砂岩储层含气性,结合煤系致密砂岩储层气测显示特征,将煤储层理论含气量与实测现场解吸气量进行相关性定量分析,建立了以"地层含气量"为指标的煤系储层含气量定量评价模型。在该模型的基础上,初步估算了库拜煤田侏罗系致密砂岩储层含气量,并从构造演化、压力特征、封堵模式等方面分析了库拜煤田煤系致密砂岩储层地质特征。结果表明:(1)库拜煤田煤系致密砂岩气气显示次数多、单层厚度大、品位中等;(2)灰色关联分析显示,砂体厚度是影响致密砂岩储层含气量的主控因素;(3)库拜煤田下侏罗统塔里奇克组致密砂岩储层含气性最好,具有良好的勘探开发潜力。

In order to quickly and accurately evaluate the gas-bearing capacity of tight sandstone reservoirs of the coal-measures of the Kubai coalfield, a quantitative gas content evaluation model of the tight sandstone reservoirs of coal-measures was established based on the index of "formation gas content", by combining the gas logging characteristics and analyzing the correlation between the theoretical gas contents of coal reservoirs and the measured desorbed gas contents of coals. The gas content of Jurassic tight sandstone reservoir in the Kubai coalfield is preliminarily estimated by using the above model, and the geological characteristics of the coal measure tight sandstone reservoir in the Kubai coalfield are analyzed from the aspects of tectonic evolution, pressure characteristics and plugging mode. The results show that:(1)tight sandstone gas in coal measures of the Kubai coalfield were detected by gas logging curves for many times. The reservoir, which is of medium grade, has single layer with large thickness;(2)grey correlation analysis shows that sand body thickness is the main controlling factor of gas content in tight sandstone reservoir;(3)the tight sandstone gas of the Lower Jurassic Taliqike formation in the Kubai coalfield has the best gas-bearing properties and has good exploration and development potential.