1.2.1.2.3 Western Coalfield

Geological conditions of the western margins of the Sydney Basin are generally not favourable for coal seam gas development as the coals are relatively immature compared to those in other coalfields, and the structural setting and shallow depth of the coals along the western margins has most likely resulted in gas escape. To date, limited studies have been conducted and reported on investigating the western margins of the Sydney Basin. Recent observations by Thomson et al. (2014, p. 401) showed that gas contents down to a depth of about 60 m are generally low as most results show gas contents of less than 0.7 m³/t with gas composition being dominated by carbon dioxide. These observations are supported by the work of Odins and Bocking (1994) who suggested that gas contents can be very low in the western regions of the basin to depths of up to 200 m.