Sedimentology and stratigraphy of an intra-cratonic basin coal seam gas play: Walloon Subgroup of the Surat Basin, eastern Australia

Abstract

Large gas reserves are trapped in the coals of the Middle Jurassic (Callovian) Walloon Subgroup (lower part of the Injure Creek Group) in the Surat Basin, eastern Australia. The series is divided into the Juandah Coal Measures (upper), Tangalooma Sandstone and Taroom Coal Measures (lower).The upper and lower units are locally further subdivided. These economically important coals were deposited in an alluvial plain setting within an interior basin, which has no recorded contemporaneous marine influence. The coals are typically bituminous, perhydrous and low rank with a high volatile content. Despite individual ply (bench) thicknesses typically less than a metre, series of plies or seams of coals up to 10 m thick have historically been tentatively correlated across the entire play area (over 150 km). 2011-043r esearch-articleArticle19X10.1144/petgeo2011-043M. A. MartinWalloon Subgroup sedimentology and stratigraphy

Conceptual exploration targeting for microbially enhanced coal bed methane (MECoM) in the Walloon Subgroup, eastern Surat Basin, Australia

“…Results of basin and maceral analysis (D. Pacey, unpubl. data;Hamilton et al, 2014b; this paper), as well as chemo-and biostratigraphy (Martin et al, 2013) imply a maximum flooding surface (MFS) in the Lower Juandah Coal Measures, which marks a transition from deepening-to shallowing-up strata. Above this MFS, progressive 13 C-enrichment of the coals is interpreted to reflect changing climatic and depositional conditions (increasing aridity and/or water table fluctuation).…”

“…Recent studies of coal geometry (Ryan et al, 2012;Sliwa and Esterle, 2008) and vertical lithofacies associations Martin et al, 2013) identified significant variation…”

“…Porosity (generally <15%) and water permeability values of Walloon Subgroup sandstones are low (generally <2 mD) (Geological Survey of Queensland, 2013; Martin et al, 2013). In contrast, coal permeability values up to 500 mD have been recorded across the eastern Surat Basin, with the permeabilities of lower Juandah coals (generally 10-100 mD) generally exceeding those of the upper Juandah and Taroom coals (<5 mD) (Ryan et al, 2012;Scott et al, 2007).…”

Characterizations and accumulation of lacustrine source rocks in the Zhu I Depression, Pearl River Mouth Basin, China

“…The depositional facies of the Wenchang Formation were analysed under a second‐order sequence stratigraphic framework (Martin, Wakefield, Macphail, Pearce, & Edwards, ; Shao, ; Wu, Hu, Liu, Zhang, & Yin, ; Zhu et al, ). In the Eocene, the main depositional facies are middle–deep lacustrine facies, shallow lacustrine facies, and delta and fan delta facies (Figure ).…”

Novel Well Test Design for the Evaluation of Complete Well Permeability and Productivity for CSG Wells in the Surat Basin

“…CSG development areas are reasonably shallow at 100-1000m below ground level and produce from moderate rank, sub-bituminous coals. The gross zone of commercial interest is typically 300-450m thick (Martin et al 2013) and comprises 10% net coal (~30m in total). Coal seams are generally thin (mean thickness: 30cm) and are interbedded with low permeability clastic rocks.…”