Improved Anderson-Hampton acoustic velocity model for marine sandy gas-bearing sediments

Anderson & Hampton model is an important theoretical foundation for detection of marine shallow gas and identification of gas-bearing sediments. In the acoustic test of sandy gas-bearing sediments, it was found that if the excitation frequency is lower than the bubble resonance frequency, this model overestimates the attenuation of compressional wave velocity of the sediments, and it is difficult to accurately determine the original occurrence status of gas in the sediments by back analysis. The main reason is that the Gassmann equation in Anderson-Hampton model does not accurately describe the modulus parameters of sandy gassy sand sediments. Based on the occurrence characteristics of marine sandy gas-bearing sediments, an improved Anderson-Hampton acoustic velocity model was established by introducing saturation Sr and an attenuation factor reflecting the decay speed of wave speed. The advantage of the new model was pointed out and the sensitivity of parameter was analyzed simultaneously.