页岩层理与含水率对声波传播影响的实验研究

An Experimental Study on the Effects of Shale Stratification and Hydration on the Transmission of Acoustic Waves

范翔宇 段美恒 张千贵 赵鹏斐 贾光圣

FANXiangyu DUANMeiheng ZHANGQiangui ZHAOPengfei JIAGuangsheng

"油气藏地质及开发工程"国家重点实验室·西南石油大学, 四川 成都 610500 西南石油大学石油与天然气工程学院, 四川 成都 610500

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China School of Petroleum and Natural Gas Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China

岩石声学特性研究是开展测井岩石力学及储层性质评价的基础工作，而页岩的声波特性受层理及水化程度影响尤为突出。为此，对层理性页岩在不同含水率条件下进行了超声波透射实验，以研究声波的传播速度及能量衰减特征。研究认为，层理倾角越大，纵、横波速度及纵横波速度比越低，而纵、横波衰减系数越高。另外，纵波速度随含水率的增加先减小后增大，纵波衰减系数反之；横波速度在含水率较低时有所减少，含水率较高时基本不变，而横波衰减系数与含水率的关系并不显著。对比分析归一化结果可知，层理倾角对纵、横波速度的影响皆大于含水率的影响。

Studies on the acoustic characteristics of rocks are the groundwork for geomechanical logging and the evaluation of reservoir properties, and the acoustic properties of shale are especially affected by its stratification and hydration. Hence, we have performed ultrasonic transmission tests on stratified shale with varying levels of hydration, to study the characteristics of the soundwaves' transmission speed and attenuation of energy under these circumstances. We have found that as the stratification angle increases, the P- and S-wave velocities and the P-to-S-wave velocity ratio decrease, while the attenuation coefficients of the P- and S-waves increase. Furthermore, as hydration increases, the velocity of P-waves first increase, then decrease at higher levels of hydration, whereas its attenuation coefficients are inversely correlated. The velocity of S-waves decreases slightly at lower levels of hydration, and basically remains unchanged at higher levels of hydration, while its attenuation coefficients are not significantly affected by hydration. A comparative analysis of the normalized results demonstrates that stratification angles have a greater effect on P- and S-wave velocities than hydration.

10.11885/j.issn.1674-5086.2016.01.08.01