000			02488nab a2200205 4500
005			20260520003100.0
008			260224s2012 xxu ing
041			_aInglés
245	0	0	_aTransmissibility Corrections and Grid Control for Shale Gas Numerical Production Forecasts
260			_a _b _csept./oct. 2012
270			_a09/05/2013 ; 09/05/2013
300			_a16 p. ; 805-821
520			_aTraducción del resúmen del autor: In the context of shale gas production, the very low effective permeability of the formation leads to flowing conditions that are essentially transient. Even after months or years of production, the pressure drop remains mainly localized around the hydraulic fractures. Using an unstructured grid, finite-volume simulator, we show that the non-linear nature of the pressure field around horizontal wells with multiple hydraulic fractures can have a non-negligible impact on shale gas production forecasts. We first show a very simple synthetic production example with a purely linear PVT (Pressure Volume Temperature). In this case, standard (linear) transmissibility derivations overestimate the forecast after 10 years by 5%, compared to the analytical solution. We propose a new approach for transmissibility derivations, based on numerical integrations of source point solutions. Resulting transmissibility values account for the strong non-linearity of the pressure field in the vicinity of the fractures and for fracture interferences. As a consequence, forecasts are significantly improved. With a real gas PVT, non-linear effects become even more critical in the vicinity of the well. While analytical solutions only partially account for these effects, numerical simulations are more accurate, provided that the grid is fine enough. In order to reduce the computational cost, long-term simulations are usually performed on a coarser grid, with coarse transmissibility corrections obtained from near-well upscaling techniques. We show that even if near-well numerical upscaling is extremely robust for conventional problems, the choice of an optimal simulation grid size becomes essential for shale gas. A recently proposed automatic adjustment of the grid to the considered problem (including permeability and time resolution) is tested.
581			_a5
773	0		_tOil and Gas Science and Technology _g67
942			_cARTICULO
100	1		_aArtus, V. _933432
100	1		_aFructus, D. _953126
999			_c187666 _d187666