Changes

==Gas in CBM==

==Gas in CBM==

Most CBM has been produced by microbial, thermal, or possibly catalytic degradation of organic material present in coal. CBM is mainly composed of methane (CH4) with variable additions of carbon dioxide (CO2), elemental nitrogen (N2), and heavier hydrocarbon, such as ethane (C2H6), and trace of propane (C3H8) and butanes (C4H10).<ref>Thakur et al. 2014. ''Coal Bed Methane – from Prospect to Pipeline''.Elsevier</ref>

Most CBM has been produced by microbial, thermal, or possibly catalytic degradation of organic material present in coal. CBM is mainly composed of methane (CH4) with variable additions of carbon dioxide (CO2), elemental nitrogen (N2), and heavier hydrocarbon, such as ethane (C2H6), and traces of propane (C3H8) and butanes (C4H10).<ref>Thakur, P., S. Schatzel, and K. Aminian, eds., 2014, Coal bed methane—from prospect to pipeline: Amsterdam, Elsevier, 440 p.</ref>

==CBM Storage==

==CBM Storage==

Trap mecanism of CBM different with gas conventional. In gas conventional, gas trap in porosity of rock. But in CBM, methane trap in microporosity of coal. This microporosity have capasity to store gas six times more than conventional gas. This microporosity created when coal began coalification process. When temperature and pressure of coal increase, matrix in coal decrease create micro pore that trap methane. The increase [[fracture]] also making fracture or cleats in coal, so making permeability in coal (Figure 2).  

Trap mechanisms of CBM differ from conventional gas. In conventional gas, gas is trapped in the porosity of rock. But in CBM, methane is trapped in the microporosity of coal. This microporosity has the capacity to store six times more gas than conventional gas. This microporosity created when coal began coalification process. When temperature and pressure of coal increase, matrix in coal decrease create micro pore that trap methane. The increase [[fracture]] also making fracture or cleats in coal, so making permeability in coal ([[:File:Figure 2 trap mechanism.JPG|Figure 2]]).  

[[File:Figure 2 trap mechanism.JPG|500px|thumbnail|center|Figure 2 Trap Mechanism. Adapted from Al-Jubari<ref>Al-Jubary et al. 2009. ''Oilfield Review Summer 2009''.21: Schlumberger</ref>]]  

[[File:Figure 2 trap mechanism.JPG|500px|thumbnail|center|{{figure number|2|}}Trap Mechanism. Adapted from Al-Jubori<ref name=Al-Jubori>Al-Jubori, A., S. Johnston, C. Boyer, S. W. Lambert, O. A. Bustos, J. C. Pashin, and A. Wray, 2009, Coalbed methane: Clean energy for the world: Schlumberger Oilfield Review, v. 21, p. 6-13</ref>]]

==CBM Production==

==CBM Production==

Methane which trapped in microporosity can be production by dewatering. Dewatering is process to displace methane with using water. Methane pulled to well bore with decreasing formation pressure. Water than moving into well bore with methane inside of water. And then water and methane separated, methane will be save in storage and water will be injected again to subsurface. CBM has slow rate production. To increase production usually stimulated with hidrolic fracture to increase permeability of coal (Figure 3).

Methane trapped in microporosity can be produced by dewatering. Dewatering is a process to displace methane using water. Methane pulled to well bore with decreasing formation pressure. Water than moving into well bore with methane inside of water. And then water and methane separated, methane will be save in storage and water will be injected again to subsurface. CBM has slow rate production. To increase production usually stimulated with hydrolic fracture to increase permeability of coal ([[:File:Figure 3 cbm production.JPG|Figure 3]]).

[[File:Figure 3 cbm production.JPG|500px|thumbnail|center|Figure 3 Coal Bed Methane Production. Adapted from Al-Jubari<ref>Al-Jubary et al. 2009. ''Oilfield Review Summer 2009''.21: Schlumberger</ref>]]  

[[File:Figure 3 cbm production.JPG|500px|thumbnail|center|{{figure number|3|}}Coal Bed Methane Production. Adapted from Al-Jubari<ref name=Al-Jubori />]]

==Future CBM==

==Future CBM==