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Australian Energy Producers Journal Australian Energy Producers Journal Society
Journal of Australian Energy Producers
RESEARCH ARTICLE (Non peer reviewed)

Prediction of groundwater impacts from coal seam gas extraction in the Surat Basin

Keith Phillipson
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Office of Groundwater Impact Assessment, Department of Natural Resources, Mines and Energy, Queensland. Email: Keith.Phillipson@dnrme.qld.gov.au

The APPEA Journal 59(2) 931-935 https://doi.org/10.1071/AJ18079
Accepted: 1 April 2019   Published: 17 June 2019

Abstract

The Queensland regulatory framework recognises that the impacts of groundwater extraction activities can overlap in areas of concentrated development. Such areas of overlapping impacts can be declared ‘cumulative management areas’ (CMAs). When a CMA is established, the Office of Groundwater Impact Assessment (OGIA) becomes responsible for carrying out a cumulative impact assessment and preparing an Underground Water Impact Report (UWIR). The Surat CMA was declared in March 2011, and since this time, two iterations of the UWIR have been published in 2012 and 2016, underpinned by a gradually evolving regional groundwater flow model. This case study presentation will examine a number novel features of the regional groundwater flow model, resulting from OGIA’s ongoing research and development program, including the development of an adapted version of the MODFLOW-USG groundwater flow modelling code and approximation of coal desaturation and dual-phase flow effects using a modified van Genuchten function. The presentation will also look at the simulation of CSG extraction using a ‘descending drain’ methodology that recognises the gas-filled nature of CSG wells and generating up-scaled properties of highly heterogenous sedimentary material by first generating stochastic realisations of fragments of these layers, and then using ‘numerical permeameters’ to determine both the expected value and stochasticity of these properties, at the regional scale.

Keywords: cumulative impact assessment, numerical permeameters, MODFLOW-USG, Queensland.

Keith Phillipson is a hydrogeologist and groundwater modeller with over 20 years’ experience in assessing and managing the impacts of groundwater extraction for water supply and resource development purposes. Keith currently directs a range of hydrogeological and groundwater modelling-related research projects within the Queensland OGIA: an organisation that is responsible for assessing and managing the impacts of CSG extraction within the Surat CMA. Keith has been involved in developing numerical models of the Surat CMA since the inception of the area in 2011, including the development of three iterations of the regional groundwater flow model used to predict impact in the 2012, 2016 and forthcoming 2019 Surat CMA UWIR.


References

GHD (2012). Report for Queensland Water Commission (QWC), Stage 2 Surat Cumulative Management Area Groundwater Model Report. Office of Groundwater Impact Assessment, Brisbane.

Herckenrath, D., Doherty, J., and Panday, S. (2015). A methodology for assessing the impact of coal bed methane extraction on regional groundwater systems Journal of Hydrology 523, 587–601.
A methodology for assessing the impact of coal bed methane extraction on regional groundwater systemsCrossref | GoogleScholarGoogle Scholar |

Office of Groundwater Impact Assessment (OGIA) (2016a). Surat CMA Underground Water Impact Report. Available at https://www.business.qld.gov.au/industries/mining-energy-water/resources/environment-water/coal-seam-gas/surat-cma/uwir

Office of Groundwater Impact Assessment (OGIA) (2016b). Groundwater Modelling Report for the Surat Cumulative Management Area. Available at https://www.business.qld.gov.au/industries/mining-energy-water/resources/environment-water/coal-seam-gas/surat-cma/technical-reports

Peaceman, D. W. (1978). Interpretation of well-block pressures in numerical reservoir simulation. Society of Petroleum Engineers Journal 18, 183–194.
Interpretation of well-block pressures in numerical reservoir simulation.Crossref | GoogleScholarGoogle Scholar |

QWC (2012). Underground Water Impact Report for the Surat Cumulative Management Area, Queensland Water Commission. Available at https://www.dnrm.qld.gov.au/__data/assets/pdf_file/0016/31327/underground- water-impact-report.pdf