7/29/2019 Coal Bed Methane 10.3.2013

1/31

COAL BED METHANE

By: Dr. Rohit Verma

7/29/2019 Coal Bed Methane 10.3.2013

2/31

Coalbed Methane (CBM) - Methane contained in coal

seams. Often referred to as virgin coalbed methane, or coal

seam gas.

Coalmine Methane (CMM) - CBM that is released from the

coal seams during coal mining.

Abandoned Mine Methane (AMM) - Methane that

continues to be released from closed and sealed mines. May

also be referred to as coal mine methane because the

liberated methane is associated with past coal mining

activity.

7/29/2019 Coal Bed Methane 10.3.2013

3/31

COAL BED METHANE

CBM IS NATURAL GAS GENERATED DURING

COALIFICATION PROCESS AND STORED IN COAL

SEAMS IN THE ADSORBED STATE ON THE

INTERNAL SURFACES OF COAL MATRIX.

THE ABILITY OF COAL TO STORE GAS IS AFUNCTION OF RANK AND DEPTH OF BURIAL.

COAL SERVES AS BOTH THE SOURCE AS

WELL AS THE RESERVOIR ROCK FOR CBM AND

CAN HOLD FIVE TO SIX TIMES THE AMOUNT OF

GAS STORED IN A CONVENTIONAL SANDRESERVOIR OF COMPARABLE SIZE.

THE PRODUCTION OF CBM IS RELATED TO

PERMEABILITY &TAKES PLACE ON

DEPRESSURISATION OF COAL BEDS THROUGH

DEWATERING.

7/29/2019 Coal Bed Methane 10.3.2013

4/31

Coalbed methane is generated during coalification process

which gets adsorbed on coal at higher pressure.

It is a mining hazard. Presence of CBM in underground mine

not only makes mining works difficult and risky, but also

makes it costly.

Even, its ventilation to atmosphere adds green house gascausing global warming.

CBM is a remarkably clean fuel if utilized efficiently. CBM is a

clean gas having heating value of approximately 8500 KCal/kg

compared to 9000 KCal/kg of natural gas.

7/29/2019 Coal Bed Methane 10.3.2013

5/31

Porosity: The porosity of coal bed reservoirs is usually very

small, ranging from 0.1 to 10%.

Adsorption capacity : Volume of gas adsorbed per unit mass

of coal. The range is usually between 100 to 800 SCF/ton.

Fracture permeability: Acts as the major channel for the gas

to flow. Higher the permeability, higher is the gas production.

Thickness of formation and initial reservoir pressure

Intrinsic Properties of Coal Affecting Gas Production

7/29/2019 Coal Bed Methane 10.3.2013

6/31

Extraction of CBM

To extract the gas, a steel-encased hole is drilled into

the coal seam (1001500 meters below ground).

As the pressure within the coal seam declines due to

natural production or the pumping of water from the

coal bed, both gas and 'produced water' come to thesurface through tubing.

Then the gas is sent to a compressor station and intonatural gas pipelines.

The water typically contains dissolved solids such as

sodium bicarbonate and chloride.

7/29/2019 Coal Bed Methane 10.3.2013

7/31

Vertical Drilling Well

7/29/2019 Coal Bed Methane 10.3.2013

8/31

7/29/2019 Coal Bed Methane 10.3.2013

9/31

IN-SEAM HORIZONTAL CBM WELL DRILLING IN

SOHAGPUR BLOCKS

Drilling in seam - directional well from a distance of 1000 m.

7/29/2019 Coal Bed Methane 10.3.2013

10/31

CBM In-seam drilling

7/29/2019 Coal Bed Methane 10.3.2013

11/31

CBM Gas Burning Along Fractured Zone,

Nonia Nalla, Asansol, Raniganj Coalfield

Nalla,

7/29/2019 Coal Bed Methane 10.3.2013

12/31

Commercial exploitation of CBM began in 1995 when

one block was awarded to a foreign operator.

By 2001, the country started auctioning CBM assets,

armed with an elaborate policy.

Compared to the oil and gas sector, the CBM policy is

relatively more investor-friendly, both in fiscal terms

as well as contractual obligations.

Investors interest was most pronounced in the third

round of bidding (2006), when 54 bids were received

for 10 blocks.

CBM POLICY & BLOCKS IN INDIA

7/29/2019 Coal Bed Methane 10.3.2013

13/31

CBM POLICY & BLOCKS IN INDIACBM Policy formulated in 1997

Attractive Fiscal & Contractual Terms

First offer of Blocks under Round-I in 2001

So far, 4 rounds of bidding completed and 33

CBM blocks covering 17,000 km awarded but only

four blocks have come to production so far. The

DGH offered 8 blocks in the first round, 9 in thesecond round, 10 in the third round and 10 in the

fourth round.

The Directorate General of Hydrocarbons will soon offer

7/29/2019 Coal Bed Methane 10.3.2013

14/31

GAS RESOURCE BASEPrognosticated Gas Resources : 400 TCF (In 15 Basin)

CBM Gas Resources Resources : 60 TCF (For 33

Blocks)

Total Gas Resources : 450 TCF (Approx)

pp

Gas Reserves Established (As on 01.08.2010)

- From Hydrocarbon Gas Resources : 104 TCF-

7/29/2019 Coal Bed Methane 10.3.2013

15/31

7/29/2019 Coal Bed Methane 10.3.2013

16/31

7/29/2019 Coal Bed Methane 10.3.2013

17/31

7/29/2019 Coal Bed Methane 10.3.2013

18/31

7/29/2019 Coal Bed Methane 10.3.2013

19/31

l b l h l b l

7/29/2019 Coal Bed Methane 10.3.2013

20/31

Global Reserves: The largest CBM resource bases lie in

the former Soviet Union, Canada, China, Australia and the

United States, however, much of the potential remains

untapped.In 2006 it was estimated that of global resources totaling

143 trillion cubic meters, only 1 trillion cubic metres was

actually recovered from reserves.

This is due to a lack of incentive in some countries

particularly in parts of the former Soviet Union where

conventional natural gas is abundant.

In the USA today coalbed methane (CBM) representsbetween two and three per cent of all gas production.

Exploitation in Canada has been somewhat slower than in

the US, but is expected to increase with the development

of new ex loration and extraction technolo ies.

l b l

7/29/2019 Coal Bed Methane 10.3.2013

21/31

Global CBM Activities

7/29/2019 Coal Bed Methane 10.3.2013

22/31

Major coal fields and CBM blocks in India

I di R

7/29/2019 Coal Bed Methane 10.3.2013

23/31

Indian ReservesThe Directorate General of Hydrocarbons of India estimates

that deposits in major coal fields (in twelve states of India

covering an area of 35,400 km2) contain approximately 4.6TCM of CBM.

Coal in these basins ranges from high volatile to low-volatile

bituminous with high ash content (10 to 40 percent), and its

gas content is between 3-16 m3/ton depending on the rank ofthe coal, depth of burial, and geotectonic settings of the

basins as estimated by the CMPDI.

In the Jharia Coalfield which is considered to be the most

prospective area, the gas content is estimated to be between

7.3 and 23.8 m3 per ton of coal within the depth range of

150m to 1200 m. Analysis indicates every 100-m increase in

depth is associated with a 1.3 m

3

increase of methanecontent.

S A WIS IS I U IO O C LOCKS

7/29/2019 Coal Bed Methane 10.3.2013

24/31

STATEWISE DISTRIBUTION OF CBM BLOCKS

7/29/2019 Coal Bed Methane 10.3.2013

25/31

7/29/2019 Coal Bed Methane 10.3.2013

26/31

i h fi l i bl k i h

7/29/2019 Coal Bed Methane 10.3.2013

27/31

With five exploration blocks, Essar is the

biggest firm exploring CBM in India having

prospective resources of 7.6 trillion cubic feet ofCBM gas.

RIL holds 3.6 trillion cubic feet of gas in itsCBM blocks.

7/29/2019 Coal Bed Methane 10.3.2013

28/31

E i t l I t

7/29/2019 Coal Bed Methane 10.3.2013

29/31

Environmental Impacts

CBM production entails both environmental benefits

and concerns. Air quality benefits arise from

(1) Substituting clean-burning methane for dirtier

fuels

(2) the burning, rather than venting into the

atmosphere, of coal bed methane released as a resultof coal mining activities (methane is 21 times more

potent a greenhouse gas than is CO2).

However, disposal of the large volumes of water

that are produced from CBM wells, in a way that

is environmentally acceptable and yet

economicall feasible is a concern.

While the regulator announces a huge prognostic reserve of 4 6

7/29/2019 Coal Bed Methane 10.3.2013

30/31

,While the regulator announces a huge prognostic reserve of 4.6trillion cubic m of methane gas in the countrys vast coal fields,

insiders in the CBM exploration sector allege a serious mismatchbetween such estimates and the reality.

OVERESTIMATIONWhile the DGH Web site suggests that only three blocks have beenrelinquished till May 2010, unofficial estimates point out thatoperators of at least one-third of the CBM blocks (out of 33) have

either relinquished their interests, or have approached theregulator to relinquish interests, till date.Insiders say operators in seven out of eight blocks awarded in thesecond round of bidding and four out of 10 blocks in the much-hyped third round (2006) have reportedly failed to establishviable reserves and preferred to forgo assets, after completion ofphase-1 of the work programme.The general observation is that Indias CBM potential is largelyrestricted to eight blocks, three of which were awarded on

nomination basis, and the rest in the first round of bidding.

7/29/2019 Coal Bed Methane 10.3.2013

31/31