利用斯通利波速度反演地层横波速度的方法与应用研究

INVERSION OF SHEAR WAVE VELOCITY USING THE BOREHOLE STONELEY WAVE

从严格的Ｂｉｏｔ－Ｒｏｓｅｎｂａｕｍ模型出发．在低频近似下得到了井孔中斯通利波相速度的解析表达式，它与Ｔａｎｇ等从简化的Ｂｉｏｔ－Ｒｏｓｅｎｂａｕｍ模型所得到的结果类似．从理论上说明了在低频近似下简化模型的合理性．在不同频率下，对其结果中所含的声系大小修正和Ｎｏｒｒｉｓ修正作了比较．利用在不同地层介质模型和测井声系下所得到的斯通利波速度的低频近似公式，对其在不同频率下反演地层横波速度的效果作了分析．最后，处理了一段Ｓｃｈｌｕｍｂｅｒｇｅｒ公司的软地层测井资料，并将反演结果同岩芯速度值作了比较．

On basis of the original Biot-Rosenbaum model, the approximate formula of Stoneley wave velocity is presented at low frequency, which is similar to that given by Tang etc. on the simplified Biot-Rosenbaum model. It shows theoretically that the simplified model is adequate in low frequency range.Comparison of the correct of the tool dimension with Norris correct is done at different frequencies. By means of the approximate formulas, which are obtained from the different medium models (including elastic solid and two phase medium)and the different source models (including a point source and a cylinder source), the effects of inversion are analyzed, respectively. Then the data of the soft formation, which was presented by Schlumberger Company, was used to inverse the shear wave velocity in this paper,and the inversion results are compared with the core-measurement values.