Volatile oil well test analysis: application of two-phase pseudo-pressure approach

Abstract

Abstract This study investigates flow behavior in the volatile oil reservoirs with two‐phase flow around the wellbore and the application of two-phase pseudo-pressure function for well test analysis in such volatile oil reservoirs. To this end, flow behavior and saturation profile of the volatile oil reservoirs with flowing bottom-hole pressure below the bubble point pressure are investigated using a synthetic reservoir model. Subsequently, well test behavior of this reservoir in drawdown and buildup tests are examined. Finally, the application of two-phase pseudo‐pressure concept is examined for analyzing well test data of the volatile oil reservoir. It is shown that two-phase flow near the wellbore causes a composite behavior in well test data with decreasing mobility during drawdowns and increasing mobility during buildups. Moreover, employing normalized two-phase pseudo-pressure function introduced in this study is found to be a suitable method for well test analysis in volatile oil reservoirs. Using the aforementioned method, effective permeability and wellbore skin are estimated by eliminating the effect of gas saturation on the well test results.

Keywords

• Volatile oil reservoir
• Two-phase well test
• Two-phase pseudo-pressure
• Radial composite behavior