Abstract
This paper provides an analysis of a widely-used pressure-volume-temperature (PVT) parameter, demonstrating common errors made in its use and the lack of detailed descriptions in common reservoir engineering texts. Use of the Y-function is a valuable tool for increasing the accuracy of bubble point measurements, and it has other important uses, but its detailed application is poorly understood, leading to unnecessary errors in one of the most fundamental PVT properties.
Best practices have been developed and are presented, to encourage proper application of the Y-function, together with detailed recommendations for setting up Excel spreadsheets to help identify the most precise bubble point, and optimize Y-function values.
More extensive use of the Y-function to obtain bubble points for down hole or surface oil samples is recommended as it could improve quality control and selection of more representative samples.
