Authors: Antoine B Jacquey Mauro Cacace Guido Blöcher Norihiro Watanabe Magdalena ScheckWenderoth
Publish Date: 2015/09/04
Volume: 110, Issue: 3, Pages: 409-428
Abstract
During geothermal operations injection and production of fluid can induce significant pore pressure and temperature changes which impact the stress field thus affecting the reservoir performance In this context the transport and mechanical properties of the porous rock can be altered by deformation of the pore and bulk volumes Different poroelastic formulations for describing the hydromechanical behavior of porous rocks are considered Additionally a formulation for the drained bulk modulus is introduced which takes into account the poroelastic behavior This poroelastic formulation has been implemented in the 3D finite element methodbased simulator OpenGeoSys to predict porosity changes Based on the porosity changes permeability variation under different loading conditions as main property controlling transport of mass and energy in porous media is determined by the Kozeny–Carman relation Triaxial laboratory experiments conducted on two different kinds of sandstones Flechtinger and Bentheimer are used to constrain parameters which control porosity changes and thus permeability changes under drained conditions and to calibrate the numerical simulations Hydrostatic loading from 1 to 70 MPa in confining stress has been simulated for Flechtinger and Bentheimer sandstones resulting in porosity and permeability decreases Results are compared to experimental measurements to evaluate the precision of each poroelastic model Reduction in porosity of 81 with about 115 error for the Flechtinger sandstone has been simulated and of 14 with about 054 error for the Bentheimer sandstone
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