New Method to Deconvolve Well-Test Data Under Changing Well Conditions

Abstract

Abstract Recent work on deconvolution allows well test interpretation engineers to combine several shut-in periods into a single, much longer deconvolved response, allowing identification of boundaries overlooked in the analysis of these individual shut-ins. Initial algorithms by von Schroeter et al (2004)1 require the individual shut-in responses to be consistent in terms of wellbore storage and skin. An alternate method by Levitan (2005)2 allows inconsistent early time responses to be combined, but requires multiple deconvolutions and an iterative search of the reservoir initial pressure. The new suggested algorithms waive the von Schroeter et al limitation without the drawbacks of the Levitan method. These algorithms are illustrated with real data coming from permanent gauges. This paper also points out the remaining limitations of the deconvolution process. This paper was written as a technical communication. It was made a short as possible in order to complement past publications1-2 on the subject. Readers are invited to use these publications for the details of the equations and a more exhaustive list of references.