gas hydrate - CCOP

INTRODUCTION
Coal (total reserves 2,121 million tons, DMF 2004) is found in many parts of the country. The
largest deposit, with 1,286 million tons of reserves, is located in the Mae Moh Basin. Other
coal-bearing basins include Saba Yoi (350 million tons) in Amphoe Saba Yoi, Songkhla;
Krabi (111 million tons) in Amphoe Mueng, Krabi; Wiang Haeng (93 million tons) in
Amphoe Wiang Haeng, Chiang Mai; Sin Pun (91 million tons) in Amphoe Tung Yai, Nakhon
Si Thammarat; and Nago (48 million tons) in Amphoe Ngao, Lampang.
These coal deposits are mainly lignite to sub and bituminous grade. The selection of the coal
deposits for the CBM study projects was based on:
• Coal grade i.e. sub-bituminous to bituminous coal.
• Depth of burial, from 120 to 300 meters, for seal consideration.
• Thickness ranging from 2-4 meters, 7-8 meters or thicker.
• Location within, or near-by, populated areas so that methane could be commercially
supplied to the local community.
Initially, two deposits were selected; namely Mae Ta in Lampang province (three wells drilled
in triangular layout with 30 meter spacing), Northern Thailand and Mae Lamao in Tak
province, Northern Thailand (total of four wells, 30 meters apart, drilled in straight line). The
service contractors on the two projects were the Chiangmai and Suranaree Universities. This
reflects the government policy to capture and enhance academic knowledge and know-how in
the belief that academic institutions will have advantages in this endeavor as compared to
private companies.
COALBED METHANE
Coalbed methane (CBM) comprises the same compound as methane in natural gas. This CBM
is normally found in coal seams. It can be produced, sold and utilized like traditional natural
gas. CBM is generated from either a biological or thermal process. The first process is a
product of microbial action while the latter is a result of increasing heat by depth of burial.
CBM can be stored in 3 different forms; as free gas, within cleats, dissolved in water or
adsorbed within the coal matrix. CBM is always almost of pipeline quality, being composed
of approximately 90-95% methane in most instances, with minor amounts of heavier
hydrocarbons, CO 2 , N 2 , O 2 , H 2 , and He. A coal seam is often saturated with water and CBM is
contained by the water pressure and travels together with groundwater. By sinking a well to a
coal bed and pumping up the fluid, CBM will be produced by separation since CBM is
generally has low in solubility in water and will emit from the water in the well before
entering the pump. The extraction of CBM thus involves pumping the available water from
the coal seam aquifer in order to reduce the water pressure that holds the gas. CBM producers
do not try to dewater the coal seam but to keep the water moving will encourage CBM
migration toward the production well.
130 New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane