Research of unconventional resources, 2005

Study on the production system of gas hydrates

Abstract

The potential of gas hydrates have attracted considerable interest particularly in recent years, as a future source of energy. It is estimated that the amount of hydrocarbon present in the form of hydrates around the world is approximately two orders of magnitude larger than the recoverable gas in conventional reservoirs.

This study reviews the potential of gas hydrates as a source of natural gas and proposed production schemes from hydrates as well as those used. It discusses the environmental and safety concerns associated with exploitation of gas hydrates. This study also summarize the status of current activities including various considerations for safe and fast drilling and improving characterization techniques, and drilling and in-situ pilot testing of production techniques.

A significant efforts are underway for drilling and production testing from onshore and offshore hydrate accumulations: the Mallik field, Northwest Territories, Canada; the Nankai trough, offshore Japan; and Gulf of Mexico and Blake Ridge, U.S. The Messoyakha field in the northwestern portion of East Siberia is the first and the only gas hydrate deposit where gas production from hydrates has reached commercial flow rates. Small-scale production testing was conducted at the Mallik 5L-38 research well using depressurization and thermal stimulation methods, two of the most commonly suggested techniques for exploration of hydrate reservoir. In the Japan, 32 wells were drilled through the BSR horizon at the water depth of 720 m to 2,033 m in 2004. Most of these research programs include detection of the hydrate-bearing zones and drilling, logging and coring the interval.

Running in parallel to these activities, experimental researches to determine physical properties of hydrates in porous media such as fluid-flow, heat transfer, kinetic and thermodynamic parameters and geomechanical properties are more required for hydrate reservoir characterization and determination of formation properties.

The result of this study provides an important element and guideline for future planning and optimal designing of hydrate drilling and production system suitable for development of gas hydrate in East Sea of Korea.