沁北盆地太原组煤层地面垂直井抽采储层改造技术研究

Research on Surface Vertical Well Drainage Reservoir Transformation Technology of Taiyuan Formation Coal Seam in Northern Qinshui Basin

调研沁北盆地地面垂直井抽采现状,产气效果整体较差,产气呈现“单驼峰”现象。从煤储特征力学特征入手,分析了影响储层改造效果控制因素,认为软煤发育(低弹性模量、高泊松比)是低产的主要原因。在分析煤岩层裂缝扩展规律的基础上,转换“煤层顶板水平井储层改造思路”,在垂直井储层改造中兼顾煤层之间的硬岩分层或围岩,即“软硬层兼顾储层选层、改造技术”,在阳泉矿区地面垂直井中进行了应用,效果显著。垂直井单层煤储层改造施工压力明显降低,压裂规模明显提高,总液量、加砂量提高25%,垂直井产气量最高突破1800 m3/d,产气稳定。研究成果可指导沁北盆地太原组煤层地面垂直井抽采。

The present situation of surface vertical well pumping in northern Qinshui basin is investigated.The effect of vertical well producing gas is poor,and the phenomenon of"single hump"is presented.The analysis shows that the development of soft coal(low elastic modulus,high Poisson's ratio)affects the effect of reservoir hydraulic fracturing and is the main reason to restrict gas production.Based on the analysis of the law of crack propagation of coal strata,the idea of reservoir reconstruction of horizontal well in roof of coal seam is transformed,and the hard rock stratification or surrounding rock reconstruction between coal seams is taken into account in vertical well reservoir reconstruction,that is,"the soft and hard layers take into account reservoir selection and reconstruction technology".It has been applied to surface vertical well in Yangquan mining area,and the effect is remarkable.The construction pressure of vertical well single-layer coal reservoir is significantly reduced,the fracturing scale is significantly increased,and the total fluid amount and sand amount are increased by 25%.The daily gas production of vertical well exceeded 1800 m/d,and gas production was stable.The research results can guide the coal seam surface vertical well pumping in Taiyuan formation,north Qinshui basin.