Semester of Graduation

Spring 2020


Master of Science in Petroleum Engineering (MSPE)


Craft & Hawkins Department of Petroleum Engineering

Document Type



This study describes the development and validation of an improved simplified model for transient two-phase flow for any pipe inclination. The simplified model proposed has been validated with field-scale test well and laboratorial data, and also compared to the state-of-the-art commercial simulator for transient two-phase flow in pipes. The results of the simplified model showed an agreement within the range of ±30% for the holdup predictions for 65% of the scenarios, and an agreement within the range of ±30% for the pressure predictions for 82% of the scenarios considered in this work.

In the oil and gas industry, transient two-phase flow is present in many production and drilling operations, such as in well unloading, well control, and managed pressure drilling. There are many commercial transient multiphase flow simulators available, which use complex numerical procedures to describe multiphase flow in pipes and estimate variables of interest, such as pressure, temperature, phase fractions, and flow regimes discretized in space and time.

Many of the transient flow scenarios encountered in the industry are considered slow transients and a rigorous transient simulator may not be necessary in these cases. With a few simplifications of the fundamentals equations, less complex models can be deployed in such cases without significantly compromising the accuracy of the results. With this consideration, and taking the fact that acquiring a license of a commercial software can be prohibitive for small operators and consulting companies, an easy-to-use and open source simulator was implemented based on the simplified transient model discussed in this work.

Committee Chair

Waltrich, Paulo