000			02000nab a2200181 4500
005			20260520001747.0
008			260224s2009 xxu
245	0	0	_aGeneralized travel-time inversion on unstructured grids
260			_a _b _cabril. 2009
270			_a2009-05-11 ; 2009-05-11
300			_a13 p. ; 175-187
520			_aResumen publicado por el autor: We propose an extension to unstructured grids for the so-called generalized traveltime inversion method for inversion of production data. The framework of the inversion method applies directly to fully unstructured grids, but there are aspects regarding sensitivities and regularization that have to be addressed. First, we propose a generalized smoothing operator for the regularization to impose smooth modification on reservoir parameters. Second, to handle reservoir models with great heterogeneity in cell sizes, we investigate the use of rescaled sensitivities (average cell volume multiplied by local sensitivity density) in the inversion. We demonstrate the utility of our extensions on three synthetic cases in 2-D. First, we validate the inversion method by applying it to a reservoir model represented both on a Cartesian and on a refined triangular grid. Second, we apply the method for a highly unstructured grid with large differences in cell sizes. Third, we consider an example with faults and non-matching connections. All examples show that our method is able to match the data with the same quality as has been obtained earlier on structured grids and without degrading the realism of the reservoir parameters. Finally, we present a simple synthetic 3D case to illustrate that using rescaled sensitivities may be important to avoid unwanted grid-effects in models with strong variations in the thickness of the stratigraphic layers.
581			_a3-4
773	0		_tJournal of Petroleum Science & Engineering _g65
942			_cARTICULO
100	1		_aStenerud, Vegard R. _941124
999			_c169724 _d169724