Application of Deconvolution Methods to Eliminate Wellbore Storage Effect in Determining the Parameters of Oil Reservoirs by Well Testing Tools

Authors

1 Department of petroleum engineering-Ahvaz Faculty of petroleum-Petroleum University of Technology (PUT)- Ahvaz - Iran

2 Master's Degree in Petroleum Engineering, Department of Petroleum Engineering, Islamic Azad University, Omidiye branch, Iran

3 Petroleum Engineering Department, Faculty of Petroleum Engineering, Petroleum University of Technology, Ahvaz, Iran

Abstract

Well testing is a reservoir engineering technique to determine the characteristics of the well, reservoir, and near wellbore. The results of well tests can be used to calculate reservoir characteristics such as permeability, initial pressures, skin effects, and reservoir geometry. Thus, well testing will enable evaluation of well production conditions, fluid sampling and prediction of field development scenarios. Well test data is analyzed based on bottom-hole pressure variations versus time. At the initial stages of well testing, the bottom-hole flow rate is very high due to the wellbore storage effect. This makes well test data analysis very difficult because tests are short. For this reason, it is necessary to accurately measure the flow at the beginning of the tests. In addition, down-hole measurement devices are very costly with low accuracy at low flow rates. If long-term well testing is not possible, obtaining maximum information from conducting a normal test with interpretation and analysis methods is the best alternative. The deconvolution method is one of the methods of interpreting and extracting well test data. Different deconvolution techniques are applied to interpret initial pressure data affected by the wellbore storage effect. This study used only the pressure response of the wellbore storage area to interpret well test data from two wells in a fractured reservoir in Iran. It compared the obtained results with Horner’s well test results. Additionally, three deconvolution techniques were used: material balance, beta, and Russell. The obtained results indicated the relative efficiency and accuracy of the techniques.

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