Abstract
Coal-seam gas production requires groundwater extraction from coal-bearing formations to reduce the hydraulic pressure and improve gas recovery. In layered sedimentary basins, the coalbeds are often separated from freshwater aquifers by low-permeability aquitards. However, hydraulic connection between the coalbed and aquifers is possible due to the heterogeneity in the aquitard such as the existence of conductive faults or sandy channel deposits. For coal-seam gas extraction operations, it is desirable to identify areas in a basin where the probability of hydraulic connection between the coalbed and aquifers is low in order to avoid unnecessary loss of groundwater from aquifers and gas production problems. A connection indicator, the groundwater age indictor (GAI), is proposed, to quantify the degree of hydraulic connection. The spatial distribution of GAI can indicate the optimum positions for gas/water extraction in the coalbed. Depressurizing the coalbed at locations with a low GAI would result in little or no interaction with the aquifer when compared to the other positions. The concept of GAI is validated on synthetic cases and is then applied to the north Galilee Basin, Australia, to assess the degree of hydraulic connection between the Aramac Coal Measure and the water-bearing formations in the Great Artesian Basin, which are separated by an aquitard, the Betts Creek Beds. It is found that the GAI is higher in the western part of the basin, indicating a higher risk to depressurization of the coalbed in this region due to the strong hydraulic connection between the coalbed and the overlying aquifer.
Résumé
La production de gaz de houille requiert l’exhaure d’eau souterraine des formations riches en charbon pour réduire la pression hydraulique et augmenter la récupération de gaz. Dans les bassins sédimentaires stratifiés, les couches de houille sont souvent séparées des aquifères d’eau douce par des aquitards de faible perméabilité. Cependant, la connexion hydraulique entre la couche de houille et les aquifères est possible en raison d’hétérogénéités dans l’aquitard, telles que la présence de failles perméables ou de dépôts de chenaux sableux. Pour les opérations d’extraction de gaz de houille, il est souhaitable d’identifier, dans un bassin, des zones où la probabilité de connexion hydraulique entre la couche de houille et les aquifères est faible afin d’éviter la perte inutile d’eau souterraine et les problèmes de production de gaz. Un indicateur de connexion, l’indicateur d’âge de l’eau souterraine (GAI) est proposé pour quantifier le degré de connexion hydraulique. La distribution spatiale du GAI peut indiquer les positions optimales pour l’extraction d’eau/gaz dans la couche de houille. Par comparaison avec les autres positions, la dépressurisation de la couche de houille là où le GAI est faible induit une faible ou absence d’interaction avec l’aquifère. Le concept de GAI est validé sur des cas synthétiques et est ensuite appliqué au bassin Galilée nord, Australie, pour évaluer le degré de connexion hydraulique entre la série houillère d’Aramac et les formations aquifères du Grand Bassin Artésien qui sont séparées par un aquitard, les lits Betts Creek. Il est montré que le GAI est plus élevé dans la partie ouest du bassin, ce qui indique un plus fort risque de dépressurisation de la couche de houille dans cette région du fait de la forte connexion hydraulique entre la couche de houille et l’aquifère sus-jacent.
Resumen
La producción de gas de una capa de carbón requiere la extracción de agua subterránea de las formaciones carboníferas para reducir la presión hidráulica y para mejorar la recuperación de gas. Las capas de carbón en las cuencas sedimentarias suelen estar separadas de los acuíferos de agua dulce por acuitardos de baja permeabilidad. Sin embargo, es posible la conexión hidráulica entre las capas de carbón y los acuíferos debido a la heterogeneidad del acuitardo, tales como la existencia de fallas conductoras o depósitos arenosos de canales. Para las operaciones de extracción de gas de las capas de carbón es deseable identificar áreas en una cuenca donde la probabilidad de conexión hidráulica entre la capa de carbón y el acuífero es baja con el fin de evitar la pérdida innecesaria de agua subterránea de los acuíferos y los problemas de producción de gas. Se propone un indicador de conexión, el indicador de la edad de las aguas subterráneas (GAI), para cuantificar el grado de conexión hidráulica. La distribución espacial del GAI puede indicar las posiciones óptimas para la extracción de gas / agua en la capa de carbón. La despresurización en el yacimiento de carbón en lugares con una baja GAI daría lugar a poca o ninguna interacción con el acuífero si se compara con las otras posiciones. El concepto de GAI se valida en los casos sintéticos y luego se aplica al sector de la Galilee Basin, Australia, para evaluar el grado de conexión hidráulica entre la Aramac Coal Measure y las formaciones acuíferas en la Great Artesian Basin, que están separadas por un acuitardo, Betts Creek Beds. Se ha encontrado que la GAI es mayor en la parte occidental de la cuenca, lo que indica un mayor riesgo de despresurización de la capa de carbón en esta región debido a la fuerte conexión hidráulica entre las capas de carbón y el acuífero que las recubre.
摘要
煤层气生产需要从含煤地层抽取地下水以减少水力压力和煤气恢复。在分层的沉积盆地中,煤层和淡水含水层通常被低透水性的隔水层分隔。然而,由于隔水层的非均匀性如存在着导水断层或砂质渠道沉积物,煤层和含水层的水力联系也是可能的。为了开采煤层气,迫切需要确定盆地内煤层和含水层水力联系可能性很低的区域,目的就是避免含水层中的地下水流失及煤气生产中出现问题。在此,提出了新的水力联系指标即地下水年龄指标,对水力联系程度进行量化。地下水年龄指标的空间分布可以表明煤层抽取气/水的最佳位置。在地下水年龄指标低的地方对煤层减压比在别的地方对煤层减压可以使与含水层产生的相互作用很小或者没有相互作用。在综合情况下对地下水年龄指标的概念进行了验证,然后应用到澳大利亚加利利盆地北部,以评价大自流盆地内Aramac煤层和含水地层之间的水力联系程度,Aramac煤层和含水地层被隔水层-- Betts Creek 地层分隔。发现,地下水年龄指标在盆地西部较高,表明在这一地区对煤层减压风险较高,因为煤层和上覆含水层的水力联系很强。
Resumo
A produção de gás de veio de carvão requer extração de água subterrânea de formações carboníferas para reduzir a pressão hidráulica e melhorar a recuperação de gás. Em bacias sedimentares, as camadas de carvão, muitas vezes, são separadas de aquíferos de água doce por aquitardos de baixa permeabilidade. Entretanto, conexão hidráulica entre a camada de carvão e o aquífero é possível devido à heterogeneidade no aquitardo, tal como a existência de falhas condutivas ou depósitos de canais arenosos. Para operações de extração de gás de veio de carvão, é desejável identificar áreas em uma bacia onde a probabilidade de conexão hidráulica entre as camadas de carvão e os aquíferos é baixa, com o objetivo de evitar perdas desnecessárias de água subterrânea e problemas de produção de gás. Um indicador de conexão, o Indicador de Idade de Água Subterrânea (IIAS), é proposto para quantificar o grau de conexão hidráulica. A distribuição espacial do IIAS pode indicar as posições ótimas para a extração de gás/água em uma camada de carvão. Despressurizando a camada de carvão em locais com baixo IIAS resulta em pequena ou nenhuma interação com o aquífero, comparado a outras localizações. O conceito de IIAS é validado em casos sintéticos e, então, é aplicado no norte da Bacia de Galileia, Austrália, para avaliar o grau de conexão hidráulica entre a Medida de Carvão de Aramac e as formações aquíferas na Grande Bacia Artesiana, que são separadas por um aquitardo, as Camadas do Córrego Betts. Verificou-se que o IIAS é maior na parte oeste da bacia, indicando um risco mais elevado para a despressurização da camada de carvão nesta região, devido à forte ligação hidráulica entre a camada de carvão e do aquífero sobrejacente.
Similar content being viewed by others
References
Allen JP, Fielding CR (2007) Sedimentology and stratigraphic architecture of the Late Permian Betts Creek Beds, Queensland, Australia. Sediment Geol 202:5–34. doi:10.1016/j.sedgeo.2006.12.010
Anna LO (2003) Groundwater flow associated with coalbed gas production, Ferron Sandstone, east-central Utah. Int J Coal Geol 56:69–95. doi:10.1016/S0166-5162(03)00077-6
Beckers J, Cook T (2013) Groundwater risks associated with coal seam gas development in the Surat and southern Bowen basins. Dept. of Natural Resources and Mines, Queensland, Australia, 175 pp
Bianchi M, Zheng C, Wilson C, Tick GR, Liu G, Gorelick SM (2011) Spatial connectivity in a highly heterogeneous aquifer: from cores to preferential flow paths. Water Resour Res 47, W05524
Birkholzer JT, Zhou Q, Tsang C-F (2009) Large-scale impact of CO2 storage in deep saline aquifers: a sensitivity study on pressure response in stratified systems. Int J Greenhouse Gas Control 3:181–194
Cao G, Zheng C, Scanlon BR, Liu J, Li W (2013) Use of flow modeling to assess sustainability of groundwater resources in the North China Plain. Water Resour Res 49(1):159–175
De Marsily G, Delay F, Gonçalvès J, Renard P, Teles V, Violette S (2005) Dealing with spatial heterogeneity. Hydrogeol J 13:161–183
Dell’Arciprete D, Vassena C, Baratelli F, Giudici M, Bersezio R, Felletti F (2014) Connectivity and single/dual domain transport models: tests on a point-bar/channel aquifer analogue. Hydrogeol J 22:761–778. doi:10.1007/s10040-014-1105-5
Diersch H (2002) FEFLOW: finite element subsurface flow and transport simulation system—reference manual. WASY, Berlin
Evans P (1980) Geology of the Galilee Basin. In: The geology and geophysics of northeastern Australia. Geological Society of Australia, Sydney, pp 299–305
Freeze RA, Cherry JA (1977) Groundwater. Prentice-Hall, Upper Saddle River, NJ
Frost C, Pearson B, Ogle K, Heffern E, Lyman R (2002) Sr isotope tracing of aquifer interactions in an area of accelerating coal-bed methane production, Powder River Basin, Wyoming. Geology 30:923–926
Gasda SE (2010) Numerical models for evaluating CO2 storage in deep saline aquifers: leaky wells and large-scale geological features. Princeton-Bergen Series on Carbon Storage, Princeton University, Princeton, NJ
Giambastiani BMS, McCallum AM, Andersen MS, Kelly BFJ, Acworth RI (2012) Understanding groundwater processes by representing aquifer heterogeneity in the Maules Creek Catchment, Namoi Valley (New South Wales, Australia). Hydrogeol J 20:1027–1044. doi:10.1007/s10040-012-0866-y
Habermehl M (2006) The Great Artesian basin, Australia. In: Foster S, Loucks D (2006) Non-renewable groundwater resources. UNESCO-IHP, IHPVI, Series 82, UNESCO, New York
Hamawand I, Yusaf T, Hamawand SG (2013) Coal seam gas and associated water: a review paper. Renew Sust Energ Rev 22:550–560
Harbaugh AW, Banta ER, Hill MC, McDonald MG (2000) MODFLOW-2000, the US Geological Survey modular ground-water model: user guide to modularization concepts and the ground-water flow process. US Geological Survey, Reston, VA
Hawkins P, Green P (1993) Exploration results, hydrocarbon potential and future strategies for the northern Galilee Basin. APPEA J 33:280–280
Helmuth M (2008) Scoping study: groundwater impacts of coal seam gas development—assessment and monitoring. Centre for Water in the Minerals Industry, The University of Queensland,St Lucia, Australia
Horne RN (1995) Modern well test analysis. Petroway, Palo Alto, CA
Jiang Z, Mariethoz G, Farrell T, Schrank C, Cox M (2015) Characterization of alluvial formation by stochastic modelling of paleo-fluvial processes: the concept and method. J Hydrol 524:367–377
Jiang Z, Mariethoz G, Raiber M, Timms W, Cox M (2016) Application of 1D paleo-fluvial process modelling at a basin scale to augment sparse borehole data: example of a Permian formation in the Galilee Basin, Australia. Hydrol Process 30:1624–1636. doi:10.1002/hyp.10747
Knudby C, Carrera J (2005) On the relationship between indicators of geostatistical, flow and transport connectivity. Adv Water Resour 28:405–421
Knudby C, Carrera J (2006) On the use of apparent hydraulic diffusivity as an indicator of connectivity. J Hydrol 329:377–389. doi:10.1016/j.jhydrol.2006.02.026
Kolditz O, Ratke R, Diersch H-JG, Zielke W (1998) Coupled groundwater flow and transport: 1. verification of variable density flow and transport models. Adv Water Resour 21:27–46. doi:10.1016/S0309-1708(96)00034-6
Koltermann CE, Gorelick SM (1996) Heterogeneity in sedimentary deposits: a review of structure-imitating, process-imitating, and descriptive approaches. Water Resour Res 32:2617–2658
Michaelides K, Chappell A (2009) Connectivity as a concept for characterising hydrological behaviour. Hydrol Process 23:517–522. doi:10.1002/hyp.7214
Morin RH (2005) Hydrologic properties of coal beds in the Powder River Basin, Montana: I, geophysical log analysis. J Hydrol 308:227–241. doi:10.1016/j.jhydrol.2004.11.006
Moya CE, Raiber M, Taulis M, Cox ME (2015) Hydrochemical evolution and groundwater flow processes in the Galilee and Eromanga basins, Great Artesian Basin, Australia: a multivariate statistical approach. Sci Total Environ 508:411–426. doi:10.1016/j.scitotenv.2014.11.099
Myers T (2009) Groundwater management and coal bed methane development in the Powder River Basin of Montana. J Hydrol 368:178–193
Oriani F, Renard P (2014) Binary upscaling on complex heterogeneities: the role of geometry and connectivity. Adv Water Resour 64:47–61. doi:10.1016/j.advwatres.2013.12.003
Remy N, Boucher A, Wu J (2009) Applied geostatistics with SGeMS: a user’s guide. Cambridge University Press, Cambridge, UK
Renard P, Allard D (2013) Connectivity metrics for subsurface flow and transport. Adv Water Resour 51:168–196. doi:10.1016/j.advwatres.2011.12.001
Sharma S, Frost CD (2008) Tracing coalbed natural gas-coproduced water using stable isotopes of carbon. Ground Water 46:329–334. doi:10.1111/j.1745-6584.2007.00417.x
Storey RG, Howard KW, Williams DD (2003) Factors controlling riffle-scale hyporheic exchange flows and their seasonal changes in a gaining stream: a three-dimensional groundwater flow model. Water Resour Res 39:1034
Timms W, Crane R, Anderson D, Bouzalakos S, Whelan M, McGeeney D, Rahman P, Guinea A, Acworth R (2014) Vertical hydraulic conductivity of a clayey-silt aquitard: accelerated fluid flow in a centrifuge permeameter compared with in situ conditions. Hydrol Earth Syst Sci Discuss 11:3155–3212
Winter TC (1999) Relation of streams, lakes, and wetlands to groundwater flow systems. Hydrogeol J 7:28–45
Zhang XM, Tong DK, Xue LL (2009) Numerical simulation of gas–water leakage flow in a two layered coalbed system. J Hydrodyn Ser B 21:692–698. doi:10.1016/S1001-6058(08)60201-2
Zinn B, Harvey CF (2003) When good statistical models of aquifer heterogeneity go bad: a comparison of flow, dispersion, and mass transfer in connected and multivariate Gaussian hydraulic conductivity fields. Water Resour Res 39:1051. doi:10.1029/2001wr001146
Acknowledgements
Funding support for this study was provided by the China Scholarship Council, and financial support from Exoma Energy Ltd. is also gratefully acknowledged. Constructive reviews from Ryan Pollyea, Konstantinos Modis, Maria-Theresia Schafmeister, Sue Duncan and an anonymous reviewer helped us improve the article.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Jiang, Z., Mariethoz, G., Schrank, C. et al. Mapping the hydraulic connection between a coalbed and adjacent aquifer: example of the coal-seam gas resource area, north Galilee Basin, Australia. Hydrogeol J 24, 2143–2155 (2016). https://doi.org/10.1007/s10040-016-1447-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10040-016-1447-2