The pore structure of a carbonate rock influence significantly the velocity of elastic wave, and also determine the velocity dispersion and attenuation caused by fluid flow. We try to build a dispersion model suitable to carbonate and compare that with experiment data. Based on elastic mechanics, we ideally classified the pore system into two groups, i.e. stiff pores with aspect ratio greater than 0.01 and compliant pores with aspect ratio less than 0.01. We use the ultrasonic velocity versus pressure curve to invert the distribution of aspect ratio of compliant pore with corresponding pore volumes, which was verified by casting thin sections and scan of micro CT. Introducing compliant pore spectrum to modify a squirt-flow model gives a more accurate velocity dispersion curve. At the same time, low and high frequency measurement of carbonate sample of water saturation was compared with the model’s prediction. Both theoretical model and experimental data show velocity dispersion in seismic frequency band, and trend of them are quite same. The discrepancy between them could cause by the experiment process, or parameters in the model, which need further investigation.
Presentation Date: Monday, September 25, 2017
Start Time: 4:20 PM
Location: 351D
Presentation Type: ORAL
