The transformation of Australia’s first commercial CSG field into a major gas project: how innovation and subsurface understanding has driven its success

Abstract

Mount Isa Mines Limited discovered coal seam gas (CSG) in the ‘Dawson Valley’ in 1991. It was the first commercial coal seam gas field in Australia, with production and sales of gas commencing circa 1994, then operated by Conoco and known as Meridian SeamGas. In 2010, Westside Corporation acquired a 51% operating interest in Meridian SeamGas from Anglo American (Anglo) and Mitsui Moura Investment Pty Ltd (MMI). Over the last 10 years, Westside has increased sales by 466% from 9 terajoules per day (TJ/d) to 42 TJ/d with gas being sold to both domestic and export markets. Further acreage acquisition to the north and south increased the asset area by 264%; now known as the Greater Meridian Fields (GMF). The steep rise in gas demand, complex market dynamics, regulatory environment, and competition from large global oil and gas operators makes it a challenging environment for smaller gas producers in Australia. Remaining agile and employing innovative approaches to optimise field development are key factors for Westside’s growth. In particular, the pad-based drilling of up dip multi-lateral wells has reduced cost and surface footprint, while enabling more efficient gas drainage. To support this field development, a more robust subsurface framework was required. Adequate knowledge of the distribution and variability of coal thickness, gas content/composition, structure, and geohazards forms the basis of the static model. It is used for resource definition and for the optimal planning and execution of multi-lateral wells, reducing drilling risks.