Rock Physics Modeling And Seismic Response Analysis Of Natural Gas Hydrates

Bottom simulating reflector(BSR)is one of the most important signs for gas hydrate identification.In order to improve the efficiency of gas hydrate reservoir description using BSR,this paper presents an improved seismic attribute analysis method to estimate the thickness and saturation of gas hydrate based on the existing research.This method combines rock physics model with spectral analysis.The wedge model for forward modeling is established using rock physics model.Then we can get the result table of forward peak to trough distance,and use the information in amplitude spectrum to describe thick gas hydrate reservoirs.The innovations of this method include:(1)judging the existence of free gas under the gas hydrate layers by using peak to trough distance of the reflection at the bottom of the gas hydrate layers,(2)describing thick gas hydrate reservoirs using the information of low frequency.We apply this improved seismic attribute analysis technique to gas hydrate in Blake Ridge,the physical properties of gas hydrate layers in this area are described.The feasibility and stability of this method are verified at the end through comparing the results described by this method with measured data,the synthetic seismogram based on the described results and the post-stack migration profile.