Effect of Clay Content on the Mechanical Properties of Hydrate-Bearing Sediments during Hydrate Production via Depressurization

Dongliang Li,Deqing Liang,Xiaoping Wu,Zhe Wang

doi:10.3390/en12142684

Abstract

The effects of sediments with different clay contents on the mechanical properties of hydrate deposits were studied using a high-pressure, low-temperature triaxial apparatus with in-situ synthesis, as well as the mechanical properties of self-developed hydrate sediments. Through multi-stage loading, triaxial compression tests were conducted by adding quartz sand with different clay contents as the sediment skeleton, and the stress–strain relationship of the shearing process and the strength of sediments with different clay contents were determined. Volumetric changes were also observed during shearing. The results show that the strength of hydrate sediments decreases with the increasing clay content of sediments; in the processes of depressurization and shearing, the hydrate samples exhibited obvious shear shrinkage, regardless of the sediment particle size.

Highlights

The demand for energy in various countries is increasing with the continued development of modern society
Different colors correspond to different clay contents
The stress–strain relationship of hydrate sediments containing clay during shearing is mainly divisible into three stages, namely elastic strain, plastic strain, and the strain yielding stage

Summary

Introduction

The demand for energy in various countries is increasing with the continued development of modern society. The resources of traditional fossil fuels have diminished due to years of exploitation and utilization, and the world is facing an increasingly severe energy crisis. The natural gas hydrates that have been discovered far offer potential energy sources with which fossil fuels may be replaced. Primarily composed of methane, are naturally distributed across various regions worldwide. Because their shapes are similar to those of ice, they are often called “combustible ice.”. The reserves of natural gas hydrates may be 2.1 × 1016 m3 , and the decomposition of methane hydrates at approximately one atmosphere can produce ~160 m3 of methane gas and ~0.87 m3 of free water [3]. It is estimated that this is roughly twice as much as all carbonaceous fossil fuel reserves in the world [4]

Methods

Results

Conclusion