正交多极子阵列声波测井在煤田勘探中的应用——以淮南顾桥煤矿补7井区为例

Application of Orthogonal Multipole Array Acoustic Logging in Coalfield Exploration--With No.7 Well Area of Guqiao Coal Mine in Huainan as an Examplar

常规的煤田测井方法难以为顶板垮塌、瓦斯突出等复杂地质问题的解决提供有效的参数。应用正交多极子阵列声波测井,结合常规测井技术可以为煤田地质提供更多的物性参数。以淮南顾桥煤矿补7井的测井资料分析为例,提取纵横波速度比参数Vp/Vs辅助于岩性解释;与常规测井成果组合计算岩石力学参数对煤层顶板稳定性进行评了价;利用横波分裂现象对地层的方位各向异性进行分析,预测裂缝发育带。补7井区应用效果显示,目标煤层段与砂泥岩地层相比,地层时差增大,纵横波速度比减小;顶板为砂质泥岩时,与泥岩相比岩石力学参数相对较高,稳定性较好;速度各向异性不仅可以描述裂缝发育程度、走向,还可以辅助于确定地应力分布状态和最大水平应力方位。实践表明,该测井手段能够为煤矿的安全生产提供了更可靠的保障。

The conventional coalfield logging method can hardly solve the complicated geological problems such as collapse of the top plate and gas outburst.These problems need new exploration tools to solve.Using the orthogonal multipole array acoustic logging based on the combination of the dipole and the monopole technique,taking the logging data analysis of No.7 Well Area of Guqiao Coal Mine in Huainan as an example.The interpretation lithology of the Vp/Vs ratio is extracted,and the stability of coal seam roof is evaluated by combining with the conventional log results.The location of gas accumulation was predicted by analyzing the anisotropy of stratum with shear wave splitting.The application No.7 Well Area shows that target coal interval is increased compare with sand and mudstone formation,the time difference of formation is increased and the aspect ratio is reduced.When the top plate is sandy mudstone,the rock mechanics parameters are relatively high compared with mudstone,so the stability of sandy mudstone is better.Anisotropy can effectively describe the development degree and trend of fracture.It determines the distribution state of ground stress and the orientation of maximum horizontal stress.Practice indicates that the logging method can provides new safety for coal mine.