Geologic modelling
Geologic modelling, geological modelling or geomodelling is the
Geomodelling is commonly used for managing
Geologic modelling is a relatively recent subdiscipline of geology which integrates structural geology, sedimentology, stratigraphy, paleoclimatology, and diagenesis;
In 2-dimensions (2D), a
Geomodelling generally involves the following steps:[3]
- Preliminary analysis of geological context of the domain of study.
- Interpretation of available data and observations as point sets or polygonal lines (e.g. "fault sticks" corresponding to faults on a vertical seismic section).
- Construction of a structural model describing the main rock boundaries (horizons, unconformities, intrusions, faults)[4]
- Definition of a three-dimensional mesh honoring the structural model to support volumetric representation of heterogeneity (see Geostatistics) and solving the Partial Differential Equations which govern physical processes in the subsurface (e.g. seismic wave propagation, fluid transport in porous media).
Geologic modelling components
Structural framework
Incorporating the spatial positions of the major formation boundaries, including the effects of faulting, folding, and erosion (unconformities). The major stratigraphic divisions are further subdivided into layers of cells with differing geometries with relation to the bounding surfaces (parallel to top, parallel to base, proportional). Maximum cell dimensions are dictated by the minimum sizes of the features to be resolved (everyday example: On a digital map of a city, the location of a city park might be adequately resolved by one big green pixel, but to define the locations of the basketball court, the baseball field, and the pool, much smaller pixels – higher resolution – need to be used).
Rock type
Each cell in the model is assigned a rock type. In a coastal
Reservoir quality
Reservoir quality parameters almost always include
Fluid saturation
Most rock is completely saturated with groundwater. Sometimes, under the right conditions, some of the pore space in the rock is occupied by other liquids or gases. In the energy industry, oil and natural gas are the fluids most commonly being modelled. The preferred methods for calculating hydrocarbon saturations in a geologic model incorporate an estimate of pore throat size, the densities of the fluids, and the height of the cell above the water contact, since these factors exert the strongest influence on capillary action, which ultimately controls fluid saturations.
Geostatistics
An important part of geologic modelling is related to geostatistics. In order to represent the observed data, often not on regular grids, we have to use certain interpolation techniques. The most widely used technique is kriging which uses the spatial correlation among data and intends to construct the interpolation via semi-variograms. To reproduce more realistic spatial variability and help assess spatial uncertainty between data, geostatistical simulation based on variograms, training images, or parametric geological objects is often used, e.g.[5]
Mineral Deposits
Geologists involved in
Technology
Geomodelling and
Geometric objects are represented with parametric curves and surfaces or discrete models such as polygonal meshes.[4][6]
Research in Geomodelling
Problems pertaining to Geomodelling cover:[7][8]
- Defining an appropriate Ontology to describe geological objects at various scales of interest,
- Integrating diverse types of observations into 3D geomodels: geological mapping data, borehole data and interpretations, seismic images and interpretations, potential field data, well test data, etc.,
- Better accounting for geological processes during model building,
- Characterizing uncertainty about the geomodels to help assess risk. Therefore, Geomodelling has a close connection to Geostatistics and Inverse problem theory,
- Applying of the recent developed Multiple Point Geostatistical Simulations (MPS) for integrating different data sources,[9]
- Automated geometry optimization and topology conservation[10]
History
In the 70's, geomodelling mainly consisted of automatic 2D cartographic techniques such as contouring, implemented as
Since its inception, geomodelling has been mainly motivated and supported by oil and gas industry.
Geologic modelling software
Software developers have built several packages for geologic modelling purposes. Such software can display, edit, digitise and automatically calculate the parameters required by engineers, geologists and surveyors. Current software is mainly developed and commercialized by oil and gas or mining industry software vendors:
- Geologic modelling and visualisation
- IRAP RMS Suite
- GeoticMine
- Geomodeller3D
- DecisionSpace Geosciences Suite
- Dassault Systèmes GEOVIA provides Surpac, GEMS and Minex for geologic modeling
- GSI3D
- Mira Geoscience provides GOCAD Mining Suite, a 3D geological modelling software that compiles, models, and analyzes for valid interpretation that honours all data.
- Seequent provides Leapfrog 3D geological modeling & Geosoft GM-SYS and VOXI 3D modelling software.
- Maptek provides Vulcan, 3D modular software visualisation for geological modelling and mine planning
- Micromine is a comprehensive and easy to use exploration and mine design solution, which offers integrated tools for modelling, estimation, design, optimisation and scheduling.
- Petrel
- Rockworks
- SGS Genesis
- Move
- SKUA-GOCAD
- Datamine Software provides Studio EM and Studio RM for geological modelling
- BGS Groundhog Desktop free-to-use software developed by the GeoAnalytics and Modelling directorate of British Geological Survey.
- Groundwater modelling
Moreover, industry Consortia or companies are specifically working at improving standardization and interoperability of earth science databases and geomodelling software:
- Standardization: GeoSciML by the Commission for the Management and Application of Geoscience Information, of the International Union of Geological Sciences.
- Standardization: RESQML(tm) by Energistics
- Interoperability: OpenSpirit, by TIBCO(r)
See also
- Numerical modeling (geology)
- Petroleum engineering
- Seismic to simulation
References
- Bolduc, A.M., Riverin, M-N., Lefebvre, R., Fallara, F. et Paradis, S.J., 2006. Eskers: À la recherche de l'or bleu. La Science au Québec : http://www.sciencepresse.qc.ca/archives/quebec/capque0606f.html
- Faure, Stéphane, Godey, Stéphanie, Fallara, Francine and Trépanier, Sylvain. (2011). Seismic Architecture of the Archean North American Mantle and Its Relationship to Diamondiferous Kimberlite Fields. Economic Geology, March–April 2011, v. 106, p. 223–240. http://econgeol.geoscienceworld.org/content/106/2/223.abstract
- Fallara, Francine, Legault, Marc and Rabeau, Olivier (2006). 3-D Integrated Geological Modeling in the Abitibi Subprovince (Québec, Canada): Techniques and Applications. Exploration and Mining Geology, Vol. 15, Nos. 1–2, pp. 27–41. http://web.cim.org/geosoc/docs/pdf/EMG15_3_Fallara_etal.pdf
- Berg, R.C., Mathers, S.J., Kessler, H., and Keefer, D. A., 2011. Synopsis of Current Three-dimensional Geological Mapping and Modeling in Geological Survey Organization, Champaign, Illinois: Illinois State Geological Survey, Circular 578. https://web.archive.org/web/20111009122101/http://library.isgs.uiuc.edu/Pubs/pdfs/circulars/c578.pdf
- Turner, A. K.; Gable, C. (2007). "A review of geological modelling. In: Three-dimensional geologic mapping for groundwater applications, Workshop extended abstracts" (PDF). Denver, Colorado. Archived from the original (PDF) on 2008-11-21.
- Kessler, H., Mathers, S., Napier, B., Terrington, R. & Sobisch, H.-G. (2007). "The present and future construction and delivery of 3D geological models at the British Geological Survey".
{{cite web}}
: CS1 maint: multiple names: authors list (link) (GSA Denver Annual Meeting. Poster) - Wycisk, P., Gossel W., Schlesier, D. & Neumann, C. (2007). "Integrated 3D modelling of subsurface geology and hydrogeology for urban groundwater management" (PDF). International Symposium on New Directions in Urban Water Management. Archived from the original (PDF) on 2008-12-17.
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: CS1 maint: multiple names: authors list (link) - Kessler, H., Mathers, S., Lelliott, M., Hughes, A. & MacDonald, D. (2007). "Rigorous 3D geological models as the basis for groundwater modelling. In: Three-dimensional geologic mapping for groundwater applications, Workshop extended abstracts" (PDF). Denver, Colorado. Archived from the original (PDF) on 2008-12-03.
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: CS1 maint: multiple names: authors list (link) - Merritt, J.E., Monaghan, A., Entwisle, D., Hughes, A., Campbell, D. & Browne, M. (August 2007). "3D attributed models for addressing environmental and engineering geoscience problems in areas of urban regeneration – a case study in Glasgow, UK. In: First Break, Special Topic Environmental and Engineering Geoscience" (PDF). pp. Volume 25, pp 79–84.
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- Kevin B. Sprague & Eric A. de Kemp. (2005) Interpretive Tools for 3-D Structural Geological Modelling Part II: Surface Design from Sparse Spatial Data http://portal.acm.org/citation.cfm?id=1046957.1046969&coll=&dl=ACM
- de Kemp, E.A. (2007). 3-D geological modelling supporting mineral exploration. In: Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposit Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication 5, p. 1051–1061. https://web.archive.org/web/20081217170553/http://gsc.nrcan.gc.ca/mindep/method/3d/pdf/dekemp_3dgis.pdf
Footnotes
- ISBN 978-90-73781-63-4. Archived from the originalon 2016-03-04. Retrieved 2013-08-20.
- ^
Fanchi, John R. (August 2002). Shared Earth Modeling : Methodologies for Integrated Reservoir Simulations. Gulf Professional Publishing (Elsevier imprint). pp. xi–306. ISBN 978-0-7506-7522-2.
- S2CID 224972986.
- ^ a b Caumon, G., Collon-Drouaillet, P., Le Carlier de Veslud, C., Sausse, J. and Viseur, S. (2009), Surface-based 3D modeling of geological structures, Mathematical Geosciences, 41(9):927–945
- S2CID 255634245.
- ISBN 978-0-19-514460-4
- ^ Caumon, G., Towards stochastic time-varying geological modeling (2010), Mathematical Geosciences, 42(5):(555-569)
- ^ Perrin, M., Zhu, B., Rainaud, J.F. and Schneider, S. (2005), Knowledge-driven applications for geological modeling, "Journal of Petroleum Science and Engineering", 47(1–2):89–104
- ^ Tahmasebi, P., Hezarkhani, A., Sahimi, M., 2012, Multiple-point geostatistical modeling based on the cross-correlation functions, Computational Geosciences, 16(3):779-79742
- ^ M.R. Alvers, H.J. Götze, B. Lahmeyer, C. Plonka and S. Schmidt, 2013, Advances in 3D Potential Field Modeling EarthDoc, 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013
- ^ Dynamic Graphics History Archived 2011-07-25 at the Wayback Machine
- ^ Origin of the Gocad software