Coal seam methane in NSW
The major coal producing basins of New South Wales are attractive targets for coal seam methane. The majority of the bituminous coal resources occur in the Sydney-Gunnedah-Bowen Basin and the Clarence-Moreton Basin along the eastern coast of Australia. These large coal-bearing basins in New South Wales have substantial thicknesses of net clean coal at depths that are suitable (250 m to 850 m) for the extraction of methane. These coals have acceptable permeabilities, good lateral continuity, appropriate maturity, and are gas-saturated.
It is estimated that the amount of methane contained within the coal seams is several times greater than the current reserves for conventional natural gas. From the perspective of coal seam methane production potential the coal-bearing basins possess appropriate depositional settings, coal distribution, appropriate depths of cover, coal rank, gas contents, and attractive coal thicknesses within suitable pay intervals.
|Sedimentary Basin||Total (billion m3||Potentially recoverable [20% recovery factor] (billion m3)|
This estimated potentially recoverable coal seam methane (511 billion m3) has an approximate energy content of 19,000 PJ. There are also strong indications of the presence of substantial coal seam gas resources in the Gloucester and Surat Basins. Over recent years there has been a dramatic increase in interest by both the coal industry and the petroleum industry in these resources.
Currently, in New South Wales there are two company projects producing gas.
- Eastern Star Gas Limited's Narrabri Power Project supplies gas from the 11.3 PJ Proved and Probable gas reserves at the Coonarah Gas Field, (approximately 12 kilometres west of Narrabri), to the Wilga Park Power Station, under a 10 year agreement with Country Energy./li>
- AGL's Camden Gas Project Stage 1, has been completed and includes 21 production wells supplying gas (up to 4.5 PJ per year) from the Ray Beddoe Treatment Plant (RPGP) to AGL Wholesale Gas Ltd from May 2001. Stage 11 is underway with a much larger plant, Rosalind Park Gas Plant (RPGP), being constructed to supply gas from 100 production wells, under a gas sales agreement with AGL for an additional 10 PJ of gas per year for 10 years.
Coal Mine Methane
Methane poses safety problems and is a limitation to high levels of productivity in underground coal mines. Drainage of the gas is required to make the coal workings safe. In the future the State's coal production will increasingly rely on underground mining and existing mines will continue to extract coal at greater depths. As a result these mining operations may need to remove increased amounts of gas in order to maintain safe working conditions and high productivity.
There are considerable commercial advantages offered by methane drained from coal seams as an energy resource. These advantages include a relatively low exploration and production cost, and convenient location close to major markets. Conventional petroleum gas is transported all the way from Moomba in South Australia in contrast.
At present Tower and Appin Collieries in the Southern Coalfield of the Sydney Basin are using methane drained from mine workings to generate electricity which is sold into the State electricity grid.
Please refer to the following publications for further details.
- New South Wales Coal Seam Methane Potential
- New South Wales Coal Industry Profile 2005
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