Pressure Buildup Analysis With Wellbore Phase Redistribution

This paper presents an analysis of the effects of well bore phase redistribution on pressure buildup tests. Wellbore phase redistribution is shown to be a well bore storage effect and is incorporated mathematically into a new solution of the diffusivity equation. Dimensionless pressure solutions based on an infinite radial reservoir are presented for typecurve matching to analyze pressure buildup tests influenced by well bore phase redistribution, and example analyses of actual field data are included. The parameters that affect phase redistribution and gas humping are documented also. This information permits analysis of many anomalous pressure buildup tests which previously could not be analyzed quantitatively.