Coal bed methane is natural gas formed during the coalification process and stored in coal seams. It is held in place by water pressure. CBM exploration involves mapping coal seams to determine their extent, thickness, permeability and gas content. Drilling uses mud circulation to remove cuttings and install casing for stability. Production involves hydraulic fracturing to increase permeability followed by dewatering to reduce water pressure and release the gas. Major CBM resources are found in Russia, China, the US, Australia and Canada while India has an estimated 1 TCM of reserves. Uses of CBM include fuel, electricity generation and supporting mine operations.

1. COAL BED METHANE
Presented by
Vivek priyadarshi
M.Sc Petroleum Geosciences
Sem-III

2. What is coal bed methane?
• Standard natural gas:
CH4
• Methane forms along with
coal
• It is held in the cleats with
the coal
• Substantial water
pressure needed to keep
methane in the coal: 400
to 1000 ft ?
Ref.www.Coalbed_methane.htm

3. " Decaying Organic matter is:
– Buried
– Cooked
– Pressurized
" Creating
– Coal
– Methane
– Other gases
The (Simplified) Science of CBM
Ref.www.Coalbed_methane.htm

4. Methane Storage in Coal
Methane in coal is:
• Adsorbed on the surfaces of the coal
• Stored as free gas in the cleats and
open pores
Ref:-www.wsgs.uwyo.edu/Coal/CBM_Info.aspx

5. CBM EXPLORATION
“act of searching thoroughly and/or travel for the sake of discovery” - Chambers

6. PARAMETERS IN CBM EXPLORATION
• Regional geology of the area
• Mapping and surveying
• Areal extent of coal seams
• Thickness of the coal seams
• Permeability in the Coal as measured by tests, logs, etc.
• Gas content data
INITIAL STAGES OF CBM EXPLORATION
 Stacking of location
 Planning strategy for cbm
- geo technical order.
- preparation of master log.

7. CBM DRILLING

8. CBM DRILLING
BORE HOLE
VERTICAL DRILLING
CONVENTIONAL VERTICAL
DRILLING

9. BORE HOLE DRILLING
• Low Clay Polymer Mud
system
• Surface casing only
• Continuous coring of
formation
• Plotting of litho columns.
• Correlation of litho columns
on the basis of borehole
data.
• Sub-surface information are
revealed and interpretations
are done. Ref:- Raniganj bore hole drilling (photograph)

10. CONVENTIONAL VERTICAL DRILLING
• Mud circulation for the
-stability of bore hole and
-removal of cuttings.
• Mud used:-
- bentonite suspension and
-PHPA (Partially hydrolyzed
polyacrylic amide)
• Casing –
2 Casing Policy (12¼” - 9⅝”, 8 ½”-
5 ½”)
• Cementation - Two stage
cementation or light weight
cementation- due to large
column of cement & low fracture
gradient of Coals.
• Casing perforations
Ref:-www.coal bed gas drilling information.htm

11. CBM PRODUCTION TECHNIQUE

12. HYDRAUFRACTURING
Ref:-www.prowell-tech.com/impulse hydrofracturing.html

13. DEWATERING
Ref:-Coalbed_methane.htm

14. Pressure drawdown profile of a single well
Water
Flow Only
Discontinuous
Gas Flow
Continuous
Gas Flow
For CBM reservoirs, we need to deplete the
reservoir pressure down low to get the gas out.

15. Source : ONGC Task Force Report 2006
SL.NO. COUNTRY COAL RESOURCES CBM RESOURCES
( BILLION TONNES) (TCM)
1 RUSSIA 6500 17-114
2 CHINA 4000 31.8
3 USA 3970 12
4 AUSTRALIA 1700 10.8
5 CANADA 7000 10.2
6 INDIA 241 1.0
7 S. AFRICA 150 3.2
8 U.K. 190 2.8
9 POLAND 160 2.8
10 GERMANY 320 2.8
11 ZIMBABWE 8 0.05
WORLD WIDE CBM
RESOURCES

16. USES OF COAL BED METHANE
• Clean burning fuel for domestic and industrial
uses.
• Motor fuel
• Cleaning of recovered substances and methane
supply to natural gas pipelines
• Electricity generation (diesel generators, gas
turbines, internal-combustion engines )
• Supporting mine operations
• Community needs (heat and electricity) of
adjacent territories
• Mine boilers – switching from coal to gas