Coalbed methane (CBM) is emerging as an important energy resource in Australia. CBM is one of the products of coalification - the process by which peat is transformed into coal during progressive burial. The initial product is biogenic gas, thermogenic gas is produced with increasing pressure and temperature and further biogenic gas may be produced after burial has ceased if the coal becomes exposed to an active groundwater system containing methanogenic bacteria. The storage of CBM within a coalbed reservoir is complex, being a mixture of free gas, dissolved gas and absorbed gas. A number of gas and coal properties govern how much and how fast a coal seam will give up its methane, but the most economically productive seams are naturally fractured or are stimulated to induce and increase fracturing. Unlike conventional gas reservoirs, the continuous production of water from a coalbed reservoir results in a corresponding progressive increase in gas production (up to a certain limit). CBM production in Australia commenced in 1996 and most of Australias coal basins are now covered by production, exploration or application licences. The Cooper Basin contains a huge volume of coal that is recognised to be the source of much of the conventionally trapped gas. No attempt has been made to explore the basin for CBM due to the generally held belief that the coals are too deep. The Weena Trough has been identified as one area in the Cooper Basin in which the Permian coals may be at depths that are economic to exploit. Two wells drilled in the period 1968-70 encountered net coal thicknesses of more than 40m with individual seams up to 18 metres. The fact that elsewhere these coals are known to be the source of much of the basins conventionally trapped gas, combined with the advances made in understanding the nature of CBM generation, storage and production, makes the Weena Trough an ideal target for evaluation

The quality, quantity and distribution of Australia's convetional petroleum resources are largely controlled by the geoloigcal evolution of its marginal basins formed during Gondwana break-up

The Triassic to Jurassic rocks of Clarence-Moreton Basin contain abundant oil-proneorganic matter of terrestrial origin particularly in the Walloon Coal Measures and to a lesserextent in the Koukandowie Formation. This is reflected in petrographic composition, pyrolysisyields, elemental composition and extractable hydrocarbon yields. Maturation levels vary fromimmature to marginally mature in the west to overmature in the eastern part of the basin inNSW. Calculations based on Rock Eval data show that significant oil generation occurred ina narrow maturation range (0.8-1.0% vitrinite reflectance) and that migration has been highlyefficient. Potential reservoirs are present in quartzose sandstones in the KoukandowieFormation, Gatton Sandstone, Ripley Road Sandstone and Raceview Formations. Maturation modelling and fission track analyses indicate that hydrocarbon generation occurred in theperiod 80-100 Ma during a period of high heat flow when the Tasman Sea spreading ridgewas adjacent to the southeastern side of the Logan Sub-basin. Despite the abundance ofoil-prone source rocks, the basin is considered to be largely gas-prone because the drainageareas for most larger structural traps are overmature. The main difficulty in exploration ispredicting the distribution of porosity and permeability which varies because of bothdepositional facies and diagenesis, even in quartzose units. The area with the greatest hydrocarbon prospectivity is the New South Wales part ofthe Logan Sub-basin which has gas potential throughout and a chance of minor oil discoveriesalong its western margin. The northern Logan Sub-basin has some prospectivity for oil andgas and the Laidley Sub-basin has minor prospectivity for oil in the Raceview Formation.

This excursion guide provides an introduction to the fluvial sedimentology of theTriassic- Jurassic Bundamba Group in the northern part of the Clarence-MoretonBasin which is situated in the southeastern part of Queensland (Fig.1). The excursion guide is written so that the major exposures of fluvial rocksbetween Ipswich and Toowoomba can be examined. Descriptions of fourteenstops are included in the guide and if all the outcrops are inspected the total roaddistance covered is about 350 km, with Brisbane as the starting and finishingpoint. Figure 2 shows the excursion route and position of the stops. The itinerarygiven at the end of this guide includes an appropriate number of stops based on aone day excursion. The area is readily accessible with most of the sediments exposed in roadcuttings along the Warrego Highway; others occur in cuttings on theClifden-Gatton Road and the Murphys Creek Road, small access roads branchingoff the Warrego Highway . All these roads provide sealed, all weather access.Great care should be taken when examining cuttings on the Warrego Highway asit carries a large volume of traffic.The Main Roads Department generally requestthat appropriate signs be erected during road cutting examination on mainhighways. There are several small towns along the Warrego Highway thatprovide accommodation and where provisions may be purchased. The city ofToowoomba is a convenient stepping off point to visit geological features in thenorthern Clarence-Moreton Basin. The data used in compiling this excursion guide is largely derived from theAustralian Geological Survey (AGSO) Bulletin 241, (Wells & O'Brien, in press),and in particular an included paper on the sedimentology of the Bundamba Group( O'Brien & Wells, in press). The reader is referred to Wells, O'Brien, Willis & Cranfield (1990), Cranfield,Hutton and Green (1989), and Cranfield, Schwarzbock and Day (1976), fordescriptions of the regional geology of the northern part of the Clarence-MoretonBasin.

Legacy product - no abstract available

Legacy product - no abstract available

REGIONAL DEEP SEISMIC of the NORTH WEST SHELF by the AGSO North West Shelf Study Group (J.B. Colwell,N.F. Exon, P.J. Hill, G.W. O'Brien, C.J. Pigram, D.C. Ramsay, H.M.J. Stagg, H.I.M. Stracktneyer, P.A. Symonds, J.B. Wilcox) PRE-JURASSIC RIFT ARCHITECTURE AND TECTONIC DEVELOPMENT, TIMOR SEA/ASHMORE CARTIER REGION by G.W. O'Brien, J.B. Wilcox, S. Baldwin, C.J. Pigram, M. Morsel & J. Ostby TECTONIC EVOLUTION OF THE BASS STRAIT REGION, AND ITS IMPLICATIONS FOR PETROLEUM POTENTIAL by J. B. Wilcox & J. Colwell THE OTWAY BASIN - A COMPLEX PASSIVE MARGIN IN SOUTHEASTERN AUSTRALIA by D. M. Finlayson, G. W. O'Brien and C. V. Reeves PHILIPPINE MARINE SEISMIC SURVEY PROJECT^10 by Chao-Shing Lee, Malcolm C. Galloway, Aidan Moore and Andrew Fraser DEEP WATER PETROLEUM PROSPECTS IN THE^12 LORD HOWE RISE REGION by P.A. Symonds & J.B. Wilcox EVOLUTION OF THE CANNING BASIN AND ITS PETROLEUM^14 SYSTEMS: PROGRESS REPORT by M. J. Jackson, J. Kennard, K.. Romine, P. Southgate, M. Sexton, R. Shaw, C. Foster, P. Jones, R. Nicoll, G. Young, I. Zeilinger

Legacy product - no abstract available

No product available. Removed from website 25/01/2019

Presention providing an update of studies currently underway at Geoscience Australian that are focused on the regional conventional and unconventional prospectivity of the Georgina and Cooper basins. For Good Oil Conference, Fremantle, 9-10 September 2014