Challenges in Well Testing Data From Multi-layered Reservoirs; a Field Case

Abstract

The analysis of well test data in multilayer reservoirs is usually a challenging problem due to the complexity of interlayer flow within reservoir; these problems are as a result of insufficient data from unique layer flow into the wellbore. Also, these kinds of tests often could not be interpreted during shut-in period. The analyzer which is used for this kind of analysis should be verified first, to achieve this purpose some attempts are made and finally the best method is provided.

In this study; a numerical simulation model is used to design synthetic models of multilayer reservoirs, and a methodology is developed to get individual layer rate versus time. The output of the model is then exported to an analytical well test analyzer, Ecrin, and the tests are analyzed as actual data. Different scenarios for testing layered reservoirs are examined to get the least errors. It was found that in order to get the right reservoir parameters it is necessary to define some efficacy coefficients, then, the well test data of a well in South Pars field were analyzed and the individual layer parameters and reservoir heterogeneity were obtained. Finally some suggestions and conclusions are made to make a complete analysis and simulating multi-layer reservoirs and a method is specified to affect the unique layer rates on analysis to have better results. Using this methodology one can evaluate productivity of wells in less time and there will be less necessity for reservoir numerical simulation.