MAJOR ADVANCE IN COALBED METHANE RESEARCH
27 June 2003 - CSIRO

Coal and gas exploration and mining companies will also benefit from the results of this unique Australian study of CBM in the Sydney Basin.

The research, carried out by CSIRO and Sydney Gas, has identified some crucial geological and geochemical factors that control gas saturation level and coal permeability, two of the most important parameters for economic production of CBM.

CSIRO Petroleum scientist Dr Mohinudeen Faiz said that, "Coal seams in the Sydney Basin contain large amounts of methane, mainly due to the presence of large amounts of high rank bituminous coals. The study showed that the methane was generated from both deep burial during the Cretaceous Period and from shallow bacterial activity during more recent geological history."

This research, and earlier studies by CSIRO, has shown that variations in the coal seam gas composition and contents in the Sydney Basin are closely related to geological structures, coal type, burial history and groundwater flow.

Dr Faiz said that the South Sydney Basin study confirmed that high purity methane mainly occurs low down in the basin and the carbon dioxide concentration generally increases higher up, and closer to, some major fracture zones. This observation can lead to fundamental understandings of the behaviour of these gases in deep coal seams elsewhere.

According to estimates by the NSW Department of Mineral Resources, the Sydney Basin may contain approximately 750 billion cubic metres of methane resources outside those areas occupied by the National Park estate, Colliery holding and urban development of which between 20-60% is potentially recoverable.

Sydney Gas' activities are concentrated in the Sydney Basin where it has 100 per cent owned interests in 5 Petroleum Exploration Licences and 2 Petroleum Production Leases covering 5.9 million acres (23,800 square kilometres). In terms of area and gas-in-place, these holdings are believed to be the world's largest CBM resource being operated by a single company.

Sydney Gas' R&D Manager, Joe Choudhury, said that, "This study has identified critical factors that can be used to delineate high production fairways having high gas saturation levels and enhanced permeability. This is a first."

"We also demonstrated another first, that these coals with secondary biogenic gas have high methane saturation levels and are more economical to produce than coals lacking secondary biogenic gases. Clearly this is very important from an industry and commercial standpoint."

"The results from this study also showed that the most likely sites for methane production lie in regions close to the basin margins, where secondary biogenic methane has been generated due to the actions of bacteria and nutrients transported in groundwater during recent geological time."

According to CSIRO's Dr Faiz, the commercial implications of this important research are clear.

"The presence of naturally occurring methane can be hazardous for mining operations. However, by harnessing methane for power generation, New South Wales could greatly benefit from a reliable, clean energy alternative, and coal mining companies could achieve significant cost efficiencies in their operations."

CSIRO develops and applies knowledge in a range of science and engineering fields to reduce costs, increase new discovery rates and improve the percentage recovery of known resources for the oil and gas industry. CSIRO research results are applied within the petroleum, energy, mining and mineral processing sectors, in order to achieve world best practice and encourage the development of strategic relationships within the Australian Petroleum CRC, and amongst other national and international peer groups, and service and operating companies.

The findings from this joint research by CSIRO and Sydney Gas have been published in the research paper 'Bio-enhancement of Coal Bed Methane Resources in the Southern Sydney Basin', which was presented at the 2003 APPEA Conference in Melbourne in March 2003.

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