Modelling of fractured carbonate reservoirs: outline of a novel technique via a case study from the Molasse Basin, southern Bavaria, Germany
Tóm tắt
Fluid flow in low-permeable carbonate rocks depends on the density of fractures, their interconnectivity and on the formation of fault damage zones. The present-day stress field influences the aperture hence the transmissivity of fractures whereas paleostress fields are responsible for the formation of faults and fractures. In low-permeable reservoir rocks, fault zones belong to the major targets. Before drilling, an estimate for reservoir productivity of wells drilled into the damage zone of faults is therefore required. Due to limitations in available data, a characterization of such reservoirs usually relies on the use of numerical techniques. The requirements of these mathematical models encompass a full integration of the actual fault geometry, comprising the dimension of the fault damage zone and of the fault core, and the individual population with properties of fault zones in the hanging and foot wall and the host rock. The paper presents both the technical approach to develop such a model and the property definition of heterogeneous fault zones and host rock with respect to the current stress field. The case study describes a deep geothermal reservoir in the western central Molasse Basin in southern Bavaria, Germany. Results from numerical simulations indicate that the well productivity can be enhanced along compressional fault zones if the interconnectivity of fractures is lateral caused by crossing synthetic and antithetic fractures. The model allows a deeper understanding of production tests and reservoir properties of faulted rocks.
Tài liệu tham khảo
Agosta F (2006) Deformation mechanisms, architecture, and petrophysical properties of large normal faults in platform carbonates and their role in the release of CO2from Earth’s interior in central Italy. PhD thesis, Stanford University
Agosta F, Prasad M, Aydin A (2007) Physical properties of carbonate fault rocks, Fucino basin (Central Italy): implications for fault seal in platform carbonates. Geofluids 7(1):19–32. doi:10.1111/j.1468-123.2006.00158.x
Anderson E (1951) The dynamics of faulting and dyke formation with application to Britain. Oliver & Boyd, Edinburg
Anderson TR, Fairley JP (2008) Relating permeability to the structural setting of a fault-controlled hydrothermal system in southeast Oregon, USA. J Geophys Res 113(B5):B05, 402. doi:10.1029/2007JB004962
Birner J, Fritzer T, Jodocy M, Schneider M, Stober I (2009) Aufbau eines geothermischen Informationssystems für Deutschland. Final Report, LIAG-Bericht, ArchivNr. 0128452, Hannover, chap Molassebecken
Birner J, Mayr C, Lutz T, Schneider M, Baumann T, Winkler A (2011) Hidrochemie und Genese der tiefen Grundwässer des Malmaquifers im Bayrischen Teil des süddeutschen Molassebeckens. Z Geol Wiss 39:291–308
Byerlee J (1978) Friction of rocks. Pageoph 116:615–626
Byerlee J (1990) Friction, overpressure and fault normal compression. Geophys Res Lett 17(12):2109–2112. doi:10.1029/GL017i012p02109
Cacas MC, Daniel JM, Letouzey J (2001) Nested geological modelling of naturally fractured reservoirs. Petrol Geosci 7(S):S43–S52. doi:10.1144/petgeo.7.S.S43, http://pg.lyellcollection.org/content/7/S/S43.abstract
Caine JS, Evans JP, Forster CB (1996) Fault zone architecture and permeability structure. Geology 24(11):1025–1028. doi:10.1130/0091-7613(1996)024h1025:FZAAPSi2.3.CO;2, http://geology.gsapubs.org/content/24/11/1025.abstract
Cheng S-W, Dey TK, Shewchuck JR (2012) Delaunay mesh generation. CRC Press, Boca Raton
Clauser C, Koch A, Hartmann A, Rath V, Mottaghy D, Pechnig R (2006) Erstellung statistisch abgesicherter thermischer und hydraulischer Gesteinseigenschaften für den flachen und tiefen Untergrund in Deutschland Phase 1—Westliche Molasse und nördlich angrenzendes Süddeutsches Schichtstufen-land. BMU-Projekt FKZ 0329985 (Final Report)
Davatzes N, Aydin A (2005) Distribution and nature of fault architecture in a layered sandstone and shale sequence: an example from the Moab fault, Utah. In: Sorkhabi R, Tsuji Y (eds) Faults, fluid flow, and petroleum traps. AAPG Memoir, vol 85, pp 153–180
Dietrich P, Helmig R, Sauter M, Hötzl H, Köngeter J, Teutsch G (eds) (2005) Flow and transport in fractured porous media. Springer, Berlin
Energiegewinnung BGH (2010) Bayerischer Geothermieatlas—Hydrothermale Energiegewinnung. Bayerisches Staatsministerium für Wirschaft, Infrastruktur, Verkehr und technologie
Ferrill DA, Morris AP, McGinnis RN (2009) Crossing conjugate normal faults in field exposures and seismic data. AAPG Bull 93(11):1471–1488. doi:10.1306/06250909039, http://aapgbull.geoscienceworld.org/content/93/11/1471.abstract
Frisch H, Huber B (2000) Ein Hydrogeologisches Modell und der Versuch einer Bilanzierung des Thermalwasservorkommens für den Malmkarst im Süddeutschen und im angrenzenden Oberösterreichischen Molassebecken. Hydrogeologie und Umwelt 20(25):43
Fritzer T (2010) Bayerischer Geothermieatlas—hydrothermale Energiegewinnung: Technik, wirtschaftliche Aspekte, Risiken, hydrothermale Grundwasserleiter in Bayern, Untergrundtemperaturen in Bayern. Bayern, Staatsministerium für Wirtschaft Infrastruktur Verkehr und Technologie. http://books.google.de/books?id=wGAnygAACAAJ
Heidbach O, Tingay M, Barth A, Reinecker J, Kurfeß D, Müller B (2010) Global crustal stress pattern based on the World Stress Map database release 2008. Tectonophysics 482:3–15. http://www.sciencedirect.com/science/article/pii/S0040195109004132
Hickman S, Zoback M, Benoit R (1998) Tectonic controls on reservoir permeability in the Dixie Valley, Nevada, geothermal field. In: Proceedings of the twenty-third workshop on geothermal reservoir engineering. Standford University, Standford
Homuth S, Götz AE, Sass I (2011) Outcrop analogue studies for reservoir characterization and prediction of deep geothermal systems in the Molasse Basin, Germany. EGU General Assembly, Wien
Hyne NJ (2001) Nontechnical guide to petroleum geology, exploration, drilling and production, 2nd edn. Pennwell Books, Tulsa
Jaeger J, Cook N, Zimmerman R (2007) Fundamentals of rock mechanics. Blackwell, Oxford
Kalbacher T, Wang W, McDermott C, Kolditz O, Taniguchi T (2005) Development and application of a cad interface for fractured rock. Environ Geol 47(7):1017–1027. 10.1007/s00254-005-1236-z
Kolditz O, Bauer S, Bilke L, Böttcher N, Delfs J, Fischer T, Görke U, Kalbacher T, Kosakowski G, McDermott C, Park C, Radu F, Rink K, Shao H, Shao H, Sun F, Sun Y, Singh A, Taron J, Walther M, Wang W, Watanabe N, Wu Y, Xie M, Xu W, Zehner B (2012) OpenGeoSys: an open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical (THM/C) processes in porous media. Environ Earth Sci 67(2):589–599. 10.1007/s12665-012-1546-x
Kuhlemann J, Kempf O (2002) Post-eocene evolution of the North Alpine Foreland Basin and its response to Alpine tectonics. Sediment Geol 152(12):45–78. doi:10.1016/S0037-0738(01)00285-8, http://www.sciencedirect.com/science/article/pii/S0037073801002858
Marshall B, Eppstein D (1992) Mesh generation and optimal triangulation. In: Du DZ, Hwang F (eds) Computing on euclidean geometry. World Scientific Publishing, Singapore, pp 23–90
Moeck I, Schandelmeier H, Holl HG (2009) The stress regime in a Rotliegend reservoir of the Northeast German Basin. Int J Earth Sci 98:1643–1654. doi:10.1007/s00531-008-0316-1
Müller C, Siegesmund S, Blum P (2010) Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir. Environ Earth Sci 61(8):1713–1724. doi:10.1007/s12665-010-0485-7
Nishida A (2010) Experience in developing an open source scalable software infrastructure in Japan. In: Taniar D, Gervasi O, Murgante B, Pardede E, Apduhan B (eds) Computational science and its applications ICCSA 2010, Lecture Notes in Computer Science, vol 6017, Springer, Berlin, pp 448–462. doi:10.1007/978-3-642-12165-4_36
O’Sullivan MJ, Pruess K, Lippmann MJ (2001) State of the art of geothermal reservoir simulation. Geothermics 30(4):395–429
Oreskes N, Shrader-Frechette K, Belitz K (1994) Verification, validation, and confirmation of numerical models in the earth sciences. Science 263:641–646. doi:10.1126/science.263.5147.641
Peska P, Zoback MD (1995) Compressive and tensile failure of inclined well bores and determination of in situ stress and rock strength. J Geophys Res 100(B7):12791–12811. doi:10.1029/95JB00319
Reinecker J, Tingay M, Müller B, Heidbach O (2010) Present-day stress orientation in the Molasse basin. Tectonophysics 482:129–138. http://www.sciencedirect.com/science/article/pii/S0040195109004119
Schultz R (2007) Abschätzung des fündigkeitsrisikos erfahrungen mit projekten. geothermische anforderungen definition:fündigkeitsrisiko erfolgswahrsheinlichkit beispiel unterhaching ausblick. Tech. rep., 18. Fachtagung der SVG, Zürich
Segura JM, Carol I (2004) On zero-thickness interface elements for diffusion problems. Int J Numer Anal Meth Geomech 28(9):947–962
Si H (2010) Constrained Delaunay tetrahedral mesh generation and refinement. Finite Elem Anal Des 46(1):33–46
Turner A (2006) Challenges and trends for geological modelling and visualisation. Bull Eng Geol Environ 65:109–127. doi:10.1007/s10064-005-0015-0
Wang W, Kolditz O (2007) Object-oriented finite element analysis of thermo-hydro-mechanical (THM) problems in porous media. Int J Numer Meth Eng 69(1):162–201
Watanabe N, Wang W, McDermott C, Taniguchi T, Kolditz O (2010) Uncertainty analysis of thermo-hydro-mechanical coupled processes in heterogeneous porous media. Comput Mech 45(4):263–280. doi:10.1007/s00466-009-0445-9
Watanabe N, Wang W, Taron J, Görke UJ, Kolditz O (2012) Lower-dimensional interface elements with local enrichment: application to coupled hydro-mechanical problems in discretely fractured porous media. Int J Numer Meth Engng 90(8):1010–1034. doi:10.1002/nme.3353
Wibberley CAJ (2008) The internal structure of fault zones: implications for mechanical and fluid-flow properties. Special Publication, Geological Society of London. http://books.google.de/books?id=ce42jBktYGsC
Wolfgramm M, Obst K, Brandes J, Koch R, Raubbach K, Thorwart K (2009) Produktivitätsprognosen geothermischer aquifere in Deutschland. In: Der Geothermiekongress 2009 conference proceedings
Zoback M (2007) Reservoir geomechanics. Cambridge University Press, Cambridge