Understanding the effects of pressures, fluid content, and fluid distributions on the elastic wave propagation in reservoir rocks is of great importance in guiding oil and gas exploration. A new theoretical model for the attenuation of partially saturated porous rock was developed by combining the mesoscale patchy saturation effects and the microscale squirt flow effects, based on the modified frame modulus of water saturated regions under pressures. Moreover, we measured the P-wave velocity and attenuation of a partially saturated sandstone with varying pressures. After calibrating the unknown parameters in the proposed model using the measured velocity, the model was employed to quantitatively characterize the P-wave attenuation. The influence of pressure and water saturation on the P-wave attenuation of the rock was further analyzed by the comparison between the modeled attenuation and the measured values. The results showed that the squirt flow effects made the attenuation calculated by the new model significantly larger than that calculated by the patchy saturation model at low pressures, and at high water saturations. Due to the fact that the new model combined both patchy saturation and squirt flow effects, the P-wave attenuation of partially saturated rocks calculated by the new model was closer to the measured attenuation, when compared with the patchy saturation model, although the modeled attenuation still slightly underestimated the measured attenuation.
Presentation Date: Wednesday, October 14, 2020
Session Start Time: 1:50 PM
Presentation Time: 2:15 PM
Location: Poster Station 12
Presentation Type: Poster