000			03032nab a2200229 4500
005			20260520004414.0
008			260224s2012 xxu ing
041			_aInglés
245	0	0	_aNumerical Studies on Two-Way Coupled Fluid Flow and Geomechanics in Hydrate Deposits
260			_a _b _cjun. 2012
270			_a22/01/2013 ; 22/01/2013
300			_a16 p. ; 485-501
520			_aTranscripción del resumen del autor: Coupled flow and geomechanics play an important role in the analysis of gas-hydrate reservoirs under production. The stiffness of the rock skeleton and the deformation of the reservoir, as well as porosity and permeability, are directly influenced by (and interrelated with) changes in pressure and temperature and in fluid- (water and gas) and solid- (hydrate and ice) phase saturations. Fluid and solid phases may coexist, which, coupled with steep temperature and pressure gradients, results in strong nonlinearities in the coupled flow and mechanics processes, making the description of system behavior in dissociating hydrate deposits exceptionally complicated. In previous studies, the geological stability of hydrate-bearing sediments was investigated using one-way coupled analysis, in which the changes in fluid properties affect mechanics within the gas-hydrate reservoirs, but with no feedback from geomechanics to fluid flow. In this paper, we develop and test a rigorous two-way coupling between fluid flow and geomechanics, in which the solutions from mechanics are reflected in the solution of the flow problem through the adjustment of affected hydraulic properties. We employ the fixed-stress split method, which results in a convergent sequential implicit scheme. In this study of several hydrate-reservoir cases, we find noticeable differences between the results from one- and two-way couplings. The nature of the elliptic boundary value problem of quasistatic mechanics results in instantaneous compaction or dilation over the domain through loading from reservoir-fluid production. This induces a pressure rise or drop at early times (low-pressure diffusion), and consequently changes the effective stress instantaneously, possibly causing geological instability. Additionally, the pressure and temperature regime affects the various phase saturations, the rock stiffness, porosity, and permeability, thus affecting the fluid-flow regime. These changes are not captured accurately by the simpler one-way coupling. The tightly coupled sequential approach we propose provides a rigorous, two-way coupling model that captures the interrelationship between geomechanical and flow properties and processes, accurately describes the system behavior, and can be readily applied to large-scale problems of hydrate behavior in geologic media.
581			_a2
773	0		_tSPE Journal _g17
942			_cARTICULO
100	1		_aKim, J. _952924
100	1		_aMoridis, G.J. _942539
100	1		_aYang, D. _921331
100	1		_aRutqvist, J. _942538
999			_c187538 _d187538