Determination of skin factor using two different methods: pressure transient analysis and production data analysis

Abstract

Skin factor is an important parameter in petroleum production engineering. Skin factor is used to optimize production, petroleum production analyzing and forecast, and help determine the Inflow Performance Relationship curve. Skin factor are usually determined by Pressure Transient Analysis which certainly causes the temporary close of the production, hence it also leads to the financial loss because of non-productive time of the well. In order to avoid this unwanted situation, this paper presented another method to determine skin factor using production data analysis. A workflow to calculate the skin factor is proposed for two different methods. The first method is based on production data analysis and the second one is based of the Pressure Transient Analysis. A process to estimate the skin factor by the Pressure Transient Analysis method was proposed which consisted of 6 main steps: collection of input data, data pre-processing, running model, model matching, selection of model, and sensitivity analysis. Another workflow using production data analysis was also proposed in this research to estimate the skin factor as well. The workflow consisted of three main steps: preparation of input data, selection of suitable flow regimes, and sensitivity analysis. The paper also pointed out the uncertainties of these two methods and how to deal with them in order to have highly reliable results. These proposed workflows for the two methods were then applied for a real case study with actual data and results were compared to analyze the feasibility of the proposed workflow. The factors affecting the accuracy of skin factor estimation were discussed also based on the obtained results. This research showed that it was possible to estimate skin factor daily based on production data because the difference between results obtained by the two methods were small and acceptable.