Effect of Permeability on Hydrate-Bearing Sediment Productivity and Stability in Ulleung Basin, East Sea, South Korea

Jung-Tae Kim,Gye-Chun Cho,Joo Yong Lee,Ah-Ram Kim,Chul-Whan Kang

doi:10.3390/en14061752

Abstract

Methane hydrate has attracted attention as a next-generation resource, and many researchers have conducted various studies to estimate its productivity. Numerical simulation is the optimal method for estimating methane gas productivity. Meanwhile, using a reasonable input parameter is essential for obtaining accurate numerical modeling results. Permeability is a geotechnical property that exhibits the greatest impact on productivity. The permeability of hydrate-bearing sediment varies based on the sediment pore structure and hydrate saturation. In this study, an empirical permeability model was derived from experimental data using soil specimens from the Ulleung Basin, and the model was applied in numerical analysis to evaluate the sediment gas productivity and ground stability. The gas productivity and stability of hydrate-bearing sediments were compared by applying a widely used permeability model and the proposed model to a numerical model. Additionally, a parametric study was performed to examine the effects of initial hydrate saturation on the sediment gas productivity and stability. There were significant differences in the productivity and stability analysis results according to the proposed permeability model. Therefore, it was found that for accurate numerical analysis, a regional permeability model should be applied.

Highlights

IntroductionClathrate hydrates are compounds of guest molecules, such as methane, ethane, and propane, with water, and they form at high pressure (typically over 0.6 MPa) and low temperature (typically less than 300 K)
Clathrate hydrates are compounds of guest molecules, such as methane, ethane, and propane, with water, and they form at high pressure and low temperature
A small change of porosity does not significantly affect the tendency of permeability according to the hydrate saturation

Summary

Introduction

Clathrate hydrates are compounds of guest molecules, such as methane, ethane, and propane, with water, and they form at high pressure (typically over 0.6 MPa) and low temperature (typically less than 300 K). Hydrates are readily formed in the deep ocean, which exhibits high pressure and low temperatures. The guest molecules ( called natural gas) in clathrate hydrates are considered to be premium fuel because they burn cleanly and produce less CO2 [1]. Approximately 230 natural gas hydrate deposits have been investigated globally, with reserves of approximately. The production of natural gas from the hydrates could contribute to sustained economic development of individual countries, and to the global warming mitigation [2]. The field-scale production tests have been conducted in only three countries (the United States, Japan and China) due to the lack of technical fundamental for field production

Methods

Results

Conclusion