Integration of discrete fracture networks and flow simulator for quantification of hydrogeological uncertainty
Resumen
In this study, a discrete fracture network model (DFN) and groundwater flow simulation were applied to a fractured aquifer of an open-pit mine. Conditional simulation of the fracture systems was developed to quantify and evaluate the uncertainty of geological structures and to predict possible hydrogeological risks associated with these uncertainties. The method used was based on the statistical characterization and simulation of spatial distribution scenarios of fracture lengths, directions and openings, as well as their influence on water flow behavior. The spatial configuration of the structures was generated using Poisson processes, while the lengths and angles were generated by Gaussian simulation. Flow simulation was performed with Modflow software. The resulting scenarios honored field data and quantified and evaluated the uncertainty associated with fracture distribution. In addition, the study was able to demonstrate the practical aspects of the proposed simulation method, which can then be applied to increase the planning and operational effectiveness of open-pit mines.
Citas
DEUTSCH, C. V. Geoestatistical reservoir modeling. New York: Oxford University Press, 2002. 376 p.
HVORSLEV, M.J., Time Lag and Soil Permeability in Ground-Water Observations. Bull. n. 36, Waterways Exper. Sta. Corps of Engrs, U.S. Army, Vicksburg, Mississippi, pp. 1-50, 1951.
INMET – Instituto Nacional de Meteorologia. Dados meteoro-lógicos: estação meteorológica de observação de superfície convencional. Disponível em: http://www.inmet.gov.br/portal/index.php?r=estacoes/estacoesConvencionais. Acesso em: jun. 2015.
KELLER, A.A.; ROBERTS, P.V.; BLUNT, M.J. Effect of fracture aperture variations on the dispersion of contaminants. Wa-ter Resour Res, v. 35, n. 1, p. 55–63, 1999. https://doi.org/10.1029/1998WR900041
LE BORGNE, T., O. BOUR, F. L. PAILLET, and J. P. CAUDAL. Assessment of preferential flow path connectivity, and hy-draulic properties at single borehole and cross-borehole scales in a fractured aquifer. J. Hydrol. Amsterdam, v. 328, n. 1–2, p. 347–359, 2006. https://doi.org/10.1016/j.jhydrol.2005.12.029
LEI, Q., LATHAM, J.-P., TSANG, C.-F. The use of discrete frac-ture networks for modelling coupled geomechanical and hydrological behaviour of fractured rocks. Comput. Geotech, v. 85, p. 151 – 176, 2017. https://doi.org/10.1016/j.compgeo.2016.12.024
LONG, J. C. S. and BILLAUX, D. M. From field data to fracture network modeling: An example incorporating spatial struc-ture. Water Resources Research, v. 23, n. 7, p. 1201–1216, 1987. https://doi.org/10.1029/WR023i007p01201
MORENO L., TSANG, Y. W., TSANG, C.-F., HALE, F. V. and Neretnieks, I., Flow and tracer transport in a single fracture: A stochastic model and its relation to some field observa-tions. Water Resources Research, v. 24, n. 12, p. 2033–2048, 1988. https://doi.org/10.1029/WR024i012p02033
NUMMER, A. R., MIRANDA, A. W. A., CASTRO, A. M. D. R. M. de, & FILHO, D. T. Análise estrutural de fraturas e falhas aplicada ao mapeamento hidrogeológico em áreas do cristalino: es-tudo preliminar no município de Seropédica, Rio de Janeiro. Águas Subterrâneas, 2003. Disponível em: https://aguassubterraneas.abas.org/asubterraneas/article/view/23969.
PARDO-IGUZQUIZA, EULOGIO; DOWD, PETER ALAN; BAL-TUILLE, J. M.; CHICA-OLMO, M. Geostatistical modelling of a coal seam for resource risk assessment. International Jour-nal of Coal Geology, v. 112, p. 134-140, 2013. https://doi.org/10.1016/j.coal.2012.11.004
POISSON. Recherches sur la probabilité des jugementsen-matièrescriminellesetmatièrecivile. Paris, Bachelier, 1837.
R. DIMITRAKOPOULOS and LI, S. Conditional simulation of faults and uncertainty assessment in longwall coal mining. In: INTERNATIONAL GEOSTATISTICS CONGRESS PROCEED-INGS, 6., 2000. [Proceedings…]. Cape Town, South Africa, 10-14, April, 2000. P. 1-12.
SUN H Q, BAO SI-YUAN, LI LIN, LIAO TAI-PING. Predicting coal mining faults using combined rock relationships. Mining Science and Technology, v. 7, n. 3-4, p. 0745–0749, 2009.
TSANG, Y. W., TSANG, C.-F., Neretnieks, I. and Moreno, L., Flow and tracer transport in fractured media: a variable aperture channel model and its properties. Water Resources Research, v. 24, n. 12, p. 2049–2060, 1988. https://doi.org/10.1029/WR024i012p02049
U.S. GEOLOGICAL SURVEY, Office of Groundwater. Status os MODFLOW Versions and MODFLOW-Related Programs Avail-able on USGS Web Pages, 2011. Disponível em: http://water.usgs.gov/nrp/gwsoftware/modflow-status-2011Jan.pdf.
