基于CCT模型的基底式胶结疏松砂岩声波速度修正模型

针对CCT(contact cement theory)模型中胶结物中心厚度为0的假设与基底式胶结疏松砂岩的地质特征不符合的问题,重新推导得到基底式胶结疏松砂岩的胶结半径表达式,给出基于CCT模型的基底式胶结疏松砂岩声波速度修正模型及其统计近似式,并将人造基底式胶结疏松砂岩的纵、横波速度的修正模型及近似式预测结果与试验测量值进行比较。结果表明:利用新推导的胶结半径表达式修正的CCT模型可应用于基底式胶结的疏松砂岩;修正模型统计近似式有效地提高了计算效率;修正模型及其近似式相对原CCT模型能够更好地预测基底式胶结的疏松砂岩声波速度。

Modified acoustic velocity model for basal cemented loose sandstone based on contact cement theory

A modified acoustic velocity model and its approximation for basal cemented loose sandstone were proposed based on contact cement theory(CCT) model which was used for the pore basal cemented loose sandstone. The thickness of the cement layer ''s center is set to be zero in the CCT model, which contradicts with characters of the basal cemented loose sandstone. To solve this problem, the expression of cementation radius of the basal cemented loose sandstone was re-derived considering the effect of the thickness of the cement layer ''s center. Thus, the modified acoustic velocity model was developed and its approximation was then given. The man-made basal cemented loose sandstone samples were used to test the modified model and its approximation. The results show that the newly derived cementation radius expression is better than the original one. With the new expression, CCT model can be applied in the basal cemented loose sandstone. The approximation can improve the calculation efficiency effectively. The modified model and its approximation can predict both compressional and shear wave velocities better than the original CCT model.