P波各向异性检测在采空区导水裂隙带探测中的应用

为了研究工作面导水裂隙带发育情况,在陕北某煤矿进行了宽方位角、小面元、高覆盖的三维地震勘探。受地震勘探精度限制,传统方法很难对裂隙发育情况进行描述。引入P波各向异性检测技术对导水裂隙带进行研究。首先,将不同方位角地震数据进行叠加、偏移处理;之后在不同方位角偏移数据上进行蚂蚁追踪,利用蚂蚁追踪数据进行各向异性检测。经各向异性检测认为裂隙发育强度与距煤层顶板距离成反比,裂隙最大发育高度为118 m。通过各向异性数据与地震振幅数据结合分析认为研究区导水裂隙尚未发育到风化基岩面,未导通萨拉乌苏组含水层。应用实践表明,P波方位各向异性裂隙检测方法能够准确预测导水裂隙带的裂隙分布特征及发育高度。

Application of P-wave anisotropy detection in detecting the conducting fracture zone

In order to study the development of water flowing fractured zone in working face,a 3D seismic exploration with wide azimuth,small facet and high coverage was carried out in a coal mine in northern Shaanxi.Limited by the accuracy of seismic exploration,it is difficult to describe the development of fractures in traditional way.A P-wave anisotropy detection technology was introduced to study the hydraulic fractured zone in this study.Firstly,the seismic data of different azimuth angles was stacked and offset processed.And then,an ant-tracking was conducted at different azimuthal offset data,and an anisotropic detection was performed with ant trace data.The anisotropy test which indicates that the fracture development intensity is inversely proportional to the distance from the roof,and the maximum height of fracture is 118 m.With the analysis of anisotropy data and seismic amplitude data,the authors can draw a conclusion that the water flowing fractures in the study area have not yet developed to the weathered bedrock surface,and not connected to the aquifer of the Sarawusu Formation.In practice,it shows that the P-wave azimuth anisotropic fracture detection method can accurately predict the distribution characteristics and development height of fractures in hydraulic fractured zone.