【摘要】 横波预测往往建立在大量假设条件下,给计算带来了较大不确定性。采用基于地震岩石物理模型预测横波速度的方法,无须预先预测干岩样弹性模量,选择控制岩石体积模量的参数作为回归变量,不存在对典型未知参数的不可靠假设条件,减少了人为原因造成的误差。鉴于研究区域地层疏松,采用有效应力作为回归变量,相比无有效应力时,预测横波速度更为精确。利用校正后3口井实测横波与预测5口井横波资料,进行波阻抗反演、纵横波速度比反演,计算结果均反映出了关键砂层组。孔隙度反演结果与测井孔隙度曲线吻合较好,而泥质含量反演效果在某种相对意义上趋势也是合理的。综合孔隙度、泥质含量反演结果,可用于评价砂岩相对含量,进而可为钻井优选有利目标。更多还原

【Abstract】 Shear wave prediction is carried out under large number of assumptions which induce more uncertainties.Based on seismic rock physics model,the approach of shear wave prediction is proposed beyond predicting elastic modulus of dry frames.It draws the regression parameters related with rock bulk modulus without creating any imaginary assumption which reduces the artificial uncertainties.Because of unconsolidated sand,considering the compaction effect,effective stress is recommended in the regression variables which increases the shear wave prediction accuracy compared with that without effective stress as input.Combined shear wave logs from measured logs in three wells after correction with predicted logs in five wells,the key sand zones are almost inverted from acoustic impedance and velocity ratio.The porosity inversion result matches well with porosity logs from petrophysics,while the volume of clay inversion result is reasonable in some extent.Therefore,the relative volume of sand can be evaluated from the inversion of porosity and volume of clay.Moreover the optimum drilling objective can be determined as well.更多还原