The present invention provides an objective bubble point pressure
determination method enables new applications of downhole PV (Pressure
Volume) test results such as in situ measurement of the bubble point
pressure for use as a quality control parameter for sampling. The present
invention provides a method and apparatus to fit data points to a curve
and to smooth these points over an interval of N points. The derivative
of the curve is determined to obtain peak acceleration. The peak
acceleration represents the bubble point pressure. This bubble point
pressure is verified by comparison to changes in fluid compressibility
and visual observation of a pressure volume plot history.