000			02388nab a2200205 4500
005			20260520001753.0
008			260224s2009 xxu
100	1		_aRutqvist, J. _942538
100	1		_aMoridis, G.J. _942539
100	1		_aGrover, T. _942540
245	0	0	_aGeomechanical response of permafrost-associated hydrate deposits to depressurization-induced gas production
260			_cjul. 2009
270			_a14/06/2010 ; 11/06/2010
300			_a12 p. ; 1-12
520			_aTranscripción del resumen del autor. In this simulation study, we analyzed the geomechanical response during depressurization production from two known hydrate-bearing permafrost deposits: the Mallik (Northwest Territories, Canada) deposit and Mount Elbert (Alaska, USA) deposit. Gas was produced from these deposits at constant pressure using horizontal wells placed at the top of a hydrate layer (HL), located at a depth of about 900 m at the Mallik site and 600 m at the Mount Elbert site. The simulation results show that general thermodynamic and geomechanical responses are similar for the two sites, but with substantially higher production and more intensive geomechanical responses at the deeper Mallik deposit. The depressurization-induced dissociation begins at the well bore and then spreads laterally, mainly along the top of the HL. The depressurization results in an increased shear stress within the body of the receding hydrate and causes a vertical compaction of the reservoir. However, its effects are partially mitigated by the relatively stiff permafrost overburden, and compaction of the HL is limited to less than 0.4%. The increased shear stress may lead to shear failure in the hydrate-free zone bounded by the HL overburden and the downward-receding upper dissociation interface. This zone undergoes complete hydrate dissociation, and the cohesive strength of the sediment is low. We determined that the likelihood of shear failure depends on the initial stress state as well as on the geomechanical properties of the reservoir. The Poisson's ratio of the hydrate-bearing formation is a particularly important parameter that determines whether the evolution of the reservoir stresses will increase or decrease the likelihood of shear failure.
581			_a1-2
773	0		_tJournal of Petroleum Science & Engineering _g67
942			_cARTICULO
999			_c170921 _d170921