WELLOG
COAL BED METHANE
WHAT IS COAL BED METHANE?
Most coal beds produce
methane gas. In many regions, the combination of thickness of the coal, gas
content and permeability add up to profitable methane gas production.
HOW IS IT PRODUCED?
Coal Bed Methane field
development is done according to well-designed plans in order to optimize gas
production, field life, and profitability. A well is drilled to the top of the
producing coal formation and cased with cement. The well is then under-reamed
into and thru the coal formation. When formation water is pumped out of the
well, reducing hydrostatic pressure, the methane gas desorbs (comes out of
solution in the coal bed) and is produced in gaseous form.
WHERE ARE THE MAJOR LOCATIONS?
The main plays are in
ALASKA has become a
new CBM player with exploration and development West of Cook Inlet, Beaufort
Sea, North Slope and Alaska Peninsula.
WHAT ARE THE TOOLS?
Because coal beds contain
very low levels of natural gamma
radiation, scintillation gamma
logging tools offer the best choice for logging a CBM well. Often times, if the
drill string has sufficient inside diameter, a slim-hole (1 1/4 inch) gamma ray
logging tool is lowered into the drill string without removal from the well and
a log is obtained thru the drill steel. Otherwise, open hole
/ cased hole gamma ray logging is performed. Perforation position within the
most desired coal seam is critical in CBM well production. Casing collar
Locator (CCL) is usually ran with natural gamma ray logging.
OLD WELLS:
Old wells drilled in coal
producing regions offer the potential for CBM gas production. Gamma ray logging
of these old wells will reveal the location of coal seams. Perforation and
production of CBM gas becomes possible.
Revised 11-07-2018 © 2018
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