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Numerical modelling of regional faults in land subsidence prediction above gas/oil reservoirs
Author(s) -
Ferronato Massimiliano,
Gambolati Giuseppe,
Janna Carlo,
Teatini Pietro
Publication year - 2007
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/nag.640
Subject(s) - geology , drawdown (hydrology) , subsidence , petroleum engineering , fault (geology) , displacement (psychology) , natural gas field , stress field , fossil fuel , geotechnical engineering , stress (linguistics) , effective stress , oil field , finite element method , petrology , natural gas , geomorphology , seismology , groundwater , engineering , psychology , linguistics , philosophy , structural engineering , aquifer , psychotherapist , structural basin , waste management
Abstract The stress variation induced by gas/oil production may activate pre‐existing regional faults. This may enhance the expected land subsidence due to the generation of mechanically weak points close to the producing field. A class of elasto‐plastic interface elements (IE), specifically designed to address the mechanical behaviour of faults over a regional scale, is integrated into a finite element (FE) geomechanical model and used to investigate the role exerted by active faults in anthropogenic land subsidence. The importance of regional faults depends on a variety of factors including depth of the depleted reservoir, fault number, orientation and size, geomechanical properties of porous medium, pore pressure drawdown induced by fluid production, etc. With the aid of some representative examples, a useful indication is provided as to where and how fault activation may influence both magnitude and extent of the land subsidence bowl above producing gas/oil reservoirs, pointing to a generally limited impact on the ground surface. The simulation of a real faulted gas reservoir in a complex 3‐D setting shows that the proposed IE can be simply and efficiently incorporated into a FE geomechanical model, thus improving the quality of the stress and displacement prediction. Copyright © 2007 John Wiley & Sons, Ltd.