Print Email Facebook Twitter A semi-analytical model for productivity testing of complex well configurations Title A semi-analytical model for productivity testing of complex well configurations Author Fokker, P.A. Brouwer, G.K. Verga, F. Ferrero, D. TNO Bouw en Ondergrond Publication year 2006 Abstract This paper presents a semi-analytical method for the modeling of productivity testing of vertical, horizontal or multilateral wells. The method, which is applicable to both oil and gas reservoirs, automatically accounts for well interference. The use of analytical expressions ensures proper handling of transient short time behavior and semi-steady-state longtime behavior, both close to the well and further into the reservoir. Calculation times are still very limited, in the order of a few minutes down to a few seconds when there are vertical wells only. This makes the tool suitable for well testing evaluation. The approach is based on an earlier derived productivity prediction tool, in which the steady-state equations were solved. It has now been extended to solve the time-dependent diffusion equation and it is thus more rigorous than the extension to time-dependent behavior using solutions to the Laplace equation and moving pressure boundaries, which was presented recently. In our current method, the equations have first been transformed using the Laplace transformation. The expressions for the producing wells are combined with auxiliary sources outside the reservoir. The core of the semi-analytic method involves an adjustment of the positions and strengths of these sources in order to approximate the boundary conditions at the reservoir boundaries. The solution that is obtained is transformed back into the time domain using a Stehfest algorithm. The new approach has been validated with numerical tools, including both reservoir simulators and well-test interpretation software. Validations were performed with artificial cases using both single-well and multiple-well production tests. The results of these tests were excellent. Subject Energy EfficiencyGeosciencesEnergy / Geological Survey NetherlandsEquations of stateLaplace transformsPetroleum reservoirsProductivityToolsWell testingAnalytical expressionsInterpretation softwareLaplace transformationsSemi-analytical methodsSteady-state equationsTime dependent behaviorTime-dependent diffusionWell-testing evaluationSoftware testing To reference this document use: http://resolver.tudelft.nl/uuid:37fb1813-9567-4f92-a643-028c5049da27 TNO identifier 493129 Publisher European Association of Geoscientists and Engineers, EAGE Source 10th European Conference on the Mathematics of Oil Recovery, ECMOR 2006, 4 September 2006 through 7 September 2006, Amsterdam Article number B23 Bibliographical note Sponsors: Shell Document type conference paper Files To receive the publication files, please send an e-mail request to TNO Library.