Laboratory validation of effective acoustic velocity models for samples bearing hydrates of different type

Abstract

This paper reports the results of a series of laboratory experiments on forming synthetic methane and tetrahydrofuran (THF) hydrates in sand samples and measuring their acoustic properties, i.e. P- and S-wave velocities. Experimental data were used for validating different effective acoustic velocity models connecting P- and S-wave velocities to the hydrate saturation. The envelope-cementing effective model gives the best fit for the methane gas-hydrate formation using the “excess-gas” method. These results may represent the case of onshore hydrate deposits formed from gas accumulations, e.g. Messoyakha Field in Siberia. The load-bearing effective model gives the best fit for THF hydrate formation that avoids gas phase in the system. These results should be typical to the most widespread hydrate deposits forms in marine sediments from the dissolved methane. We compare our experimental data with a compilation of similar published results to confirm their reliability and support our conclusions. Calibrated effective models can be further used for developing seismic-exploration methods for characterizing as well as confirming the origination history of natural gas-hydrate accumulations of different type.