Pressure Build Up Analysis with Wellbore Phase Redistribution (Pressure Derivative Approach)

This study presents a new mathematical model which uses type curves, for the analysis of the effects of well bore phase redistribution on pressure build up tests, based on the principle of superposition. Well bore phase redistribution is shown to be a well bore storage effect and is incorporated mathematically into the diffusivity equation. The parameters that affect phase redistribution and gas humping are also documented. The derivative of the dimensionless well bore pressure was included in the type curves and in the data which makes the matching process much easier, and the method used in this study is validated with actual field data. This study permits analysis of many anomalous pressure buildup tests, which previously could not be analyzed quantitatively.