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Finite element modelling of hydraulic fracture flow in porous media. / Mauricio Centeno Lobao
Swansea University Author: Mauricio Centeno Lobao
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In the present thesis, a computational framework for the analysis of coupled hydro-fracture flow in deformable porous media using a Finite/Discrete Element Method is presented. In this context, a series of developments have been made in order to provide a more efficient and robust numerical model ca...
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In the present thesis, a computational framework for the analysis of coupled hydro-fracture flow in deformable porous media using a Finite/Discrete Element Method is presented. In this context, a series of developments have been made in order to provide a more efficient and robust numerical model capable of dealing with oil production and slope stability problems. The mechanical response of the skeleton is highly dependent on its seepage behaviour as pore pressure modifications affect the in situ stress field. The u-p formulation has been employed using an explicit time integration scheme where fully saturated and single-phase partially saturated analysis are incorporated for 2-D and 3-D cases. Owing to their inherent simplicity, low order elements provide an excellent framework in which contact conditions coupled with crack propagation can be dealt with in an effective manner. For linear elements this implies single point integration which, however, can result in spurious zero-energy modes. Therefore, in order to obtain reliable results, a stabilization technique has been devised to eliminate hourglassing. The success of the modelling strategy ultimately depends on the interdependence of different phenomena. The linking between the displacement components, network and pore pressures represents an important role in the efficiency of the overall coupling procedure. Therefore, a master-slave technique is proposed to link seepage and network fields, proving to be particularly attractive from a computational cost point of view. Another important development that has provided substantial savings in CPU times is the use of an explicit-explicit subcycling scheme. Numerical examples have been used to assess the accuracy and efficiency of the proposed framework. Special attention is focused on the investigation of hydraulic fracture propagation in oil production problems and plane failure analysis of the stability of slopes.
Civil engineering.;Hydraulic engineering.;Geological engineering.;Petroleum engineering.
College of Engineering