沁水盆地柿庄北区块3号煤层裂缝预测

发布时间：2019-03-15 19:52

【摘要】：柿庄北地区位于沁水盆地东南部,是我国重要的煤层气产区。煤层裂缝作为主要的渗流通道,对煤层气高产富集起到重要控制作用。该区山西组3号煤层中褶皱轴部走向为近南北向,野外露头区发育一组共轭剪裂缝,优势方位为NW与近EW向,其次是近SN向。根据构造形迹确定燕山期应力场以SEE105°挤压为主。利用水力加砂压裂法对现今井点目的层地应力进行计算,通过古地磁定向与声速各向异性确定现今最大水平主应力方向为NE55°。将煤层构造与地表起伏形态作为主要影响因素,采用有限元法对燕山期及现今地应力场进行数值模拟,利用弹性力学理论对裂缝参数进行计算,计算结果认为柿庄北3号裂缝孔隙度、渗透率普遍较小,整体上中部背斜区中部平缓区东部单斜区中部向斜区西部地区。模拟的裂隙特征与实测数据所反映的裂缝特征相近,单井产气量高的地区,裂隙较发育。
[Abstract]:Shizhuang North area, located in the southeast of Qinshui Basin, is an important coal bed methane producing area in China. As the main seepage channel, coal seam fractures play an important role in controlling the high yield and enrichment of coalbed methane. The axial strike of fold in No. 3 coal seam of Shanxi formation is nearly north-south direction, and a group of conjugate shear fractures are developed in the outcrop area of Shanxi formation. The dominant orientation is NW and near EW direction, followed by near SN direction. According to the tectonic trace, the stress field of Yanshanian period is mainly SEE105 掳extrusion. The hydraulic sand fracturing method is used to calculate the ground stress of the target layer at the present well point. The direction of the maximum horizontal principal stress is determined to be NE55 掳by paleomagnetic orientation and sound velocity anisotropy. Taking the coal seam structure and surface undulation shape as the main influencing factors, the finite element method is used to simulate the Yanshanian and present geostress fields, and the fracture parameters are calculated by the elastic mechanics theory. The calculated results show that the porosity and permeability of fracture No. 3 in Shizhuang No. 3 are generally small, and the whole upper central anticline region in the middle level region in the eastern monoclinic region in the central syncline region in the western region. The simulated fracture characteristics are similar to those reflected by the measured data. In the area with high gas production per well, the fractures are more developed.
【作者单位】：中国石油大学(华东)地球科学与技术学院;中国石油大庆油田有限责任公司;中国石油冀东油田公司勘探开发研究院;
【基金】：国家科技重大专项课题(2011ZX05042-001)~~
【分类号】：P618.13

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