Acoustic characterization of hydrate formation and decomposition in clay-bearing sediments  

作　　者：Yi-Jian Zhu Xiao-Mei Yang Xing Huang Hao Li Xiao-Hui Wang Yi-Fei Sun Peng Xiao Chang-Yu Sun Guang-Jin Chen 

机构地区：[1]State Key Laboratory of Heavy Oil Processing,College of Chemical Engineering and Environment,China University of Petroleum,Beijing,102249,China

出　　处：《Petroleum Science》2024年第4期2830-2838,共9页石油科学（英文版）

基　　金：financially supported by the National Key Research and Development Program of China (No.2021YFC2800902);the Basic Research Program of Qinghai Province (2023-ZJ-703);the National Natural Science Foundation of China (Nos.22178379,22127812)。

摘　　要：Understanding the acoustic characteristics of hydrates in various sediments is crucial for hydrate resource detection and safe and efficient exploitation,as hydrate occurrence patterns vary greatly in different sediments.In this work,sediments with different bentonite contents,water saturations,and types were prepared to investigate the characteristics of P-wave velocity(reflecting the magnitude of hydrate saturation in the sediment)and amplitude(reflecting the degree of hydrate-sediment cementation)during hydrate formation and depressurization.During hydrate formation,the P-wave velocity and amplitude have similar trends.As clay content increases,the P-wave velocity increase rates quickened.On the other hand,the increased rate of P-wave velocity slows down with the increase of water saturation in the clay-bearing sediments.Comparing various types of sediment shows that the water absorption and swelling of bentonite reduce the pore space,speeding up the cementation of the hydrate with the sediment and increasing P-wave velocity at a faster rate.Correspondence between P-wave velocity and hydrate saturation is strongly related to sediment type,clay content,and water saturation.The rapidly decreasing amplitude in the early stage of hydrate depressurization indicates that hydrate in clay-bearing sediments is weakly cemented to the sediments,which is prone to stratigraphic instability.The findings of this study offer guidance for hydrate resource assessments in clay-bearing sediments as well as geologic risk estimations during hydrate mining.

关 键 词：Gas hydrate BENTONITE ILLITE P-wave velocity Amplitude 

分 类 号：TE31[石油与天然气工程—油气田开发工程]