ABSTRACT: The Dingo Field: Unlocking a Central Australian Treasure of Proterozoic Gas

DECKELMAN, JAMES ALAN, Magellan Petroleum Australia Limited, Brisbane, Queensland, Australia

The Dingo gas field is located in the northeastern part of the Amadeus basin, central Australia. The field was discovered in 1981 when Dingo No. 1, drilled on a seismically-defined structural high, flowed gas at a rate of 41,060 cu m/day (1.45 MMSCFD) from the basal part of the late Proterozoic-Cambrian Arumbera Sandstone. A second well, drilled in 1984, confirmed the integrity of the reservoir and a third well, drilled in 1990, expanded the limits of the field. In 1991, when production testing showed that the reservoir was capable of sustaining a deliverability of greater than 141,584 cu m/day (5.0 MMSCFGD), the potential commerciality of the field became clear. Encouraged by the results of the production testing, a fourth well has been scheduled for late 1991.

The Dingo field reservoir consists of lower delta-plain arkosic and subarkosic sands. These sands comprise an important part of a large, northeasterly prograding deltaic complex that spanned the Amadeus basin in the late Proterozoic and early Cambrian. Reservoir sands have up to 16.2% porosity and 11.9 md permeability in core, up to 21% porosity on logs and, collectively, up to 13.7 m of net pay. Secondary porosity, generated primarily by the dissolution of feldspar, dominates.

A simple, unfaulted, elongate anticline, stretching over 20 km along its axis, traps the gas at the field. Gas-in-place, comprising 86% methane and lesser amounts of heavier hydrocarbon gases and nitrogen, is conservatively estimated at 8.5 x 10{9} cu m (300 BCF). Marine shale in the Proterozoic Pertatataka Formation is the probable source of the gas.

Through years of perseverance, a promising resource of gas has been unlocked. With production infrastructure in place to the north and enthusiastic markets to the south, the Dingo field is well placed to contribute to the Northern Territory and South Australian supply of gas for decades to come.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)