Abstract: The reservoir pressure is generally higher than the bubble point pressure, but the flowing bottom-hole pressure is often lower than it. The near-wellbore tends to appearing partial oil degasification. This phenomenon is usually neglected. However, the single-phase flowing formula used for calculation of horizontal well productivity in this case may cause a bigger error. This paper simplifies the flowing model and conducts an infinitesimal processing of the two-phase flowing zone, thus establishing a more reasonable method for calculating horizontal well productivity with partial oil degasification. This method can also be used to calculate the limit oil productivity and the limit producing pressure differential of horizontal well.

Key words: horizontal well, degasification, productivity, formula, equation