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

Key words:  porosity medium acoustics  acoustic velocity models  contact cement theory(CCT) model  thickness of cement layer 's center  basal cemented loose sandstone  approximation of model

Abstract:

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.