COALBED METHANE CBM

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COALBED METHANE (CBM)

• DECIMA ASAMBLEA Y CONGRESO ANUAL DE NATURGAS

CARTAGENA, MARZO 29 DE 2006
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WHAT IS COALBED METHANE (CBM)?

• COALBED METHANE, CBM, IS GAS FORMED WHEN PLANT
  MATERIAL IS CONVERTED INTO COAL. PRESSURE FROM
  OVERLYING ROCK AND SORROUNDING WATER KEEPS CBM
  MOLECULARLY BONDED TO THE SURFACE OF THE COAL.
• GENERALLY CBM IS A SWEET GAS WITH A METHANE
  CONTENT OF ABOUT OF 95.
• TRACE AMOUNTS OF FOLLOWING GASES COULD BE
  PRESENT
• ETHANE
• PROPANE
• BUTANE
• CARBON DIOXIDE
• NITROGEN

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CBM AND COAL RANK
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CBM AND NATURAL GAS DEPOSITS
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CBM PRODUCTION
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SCHEMATIC DIAGRAM OF A CBM OPEN-HOLE
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CUT-OFF LIMITS
180m Gas Content Cutoff
Coal Seam
1000m Permeability Cutoff
Schematic indicating upper and lower depth cut
offs for resource calculation.
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DRILL SPACING
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KEY DATA

• CBM is generally a "sweet gas" (gt95 methane) and
  of pipeline quality
• 1000 ft3 CBM 1 million btu 37 kg coal
• 1 ton coal 28 million btu 28 000 ft3 CBM
• Typical spacing for CBM wells varies from 120 to
  30 ha.
• Cerrejón might imply more wells per acre
  (dipping, faulty structure, bed width and 25
  seams, no international experience).
• Possible exploitable resources 1-2 Trillion
  cubic feet.