Computationally efficient simulation of non-isothermal two-phase flow during well construction using a new reduced drift-flux model

Abstract

• A novel reduced drift-flux model for non-isothermal two-phase flow is developed. • This model considers transient heat transfer and gas-in-oil solubility behavior. • This model shows higher accuracy compared to historical reduced drift-flux models. • This model runs two orders of magnitude faster than real-time. • This model is validated using both field data and benchmark models. Two-phase flow modeling is important in well construction field for well planning and real-time applications. In this paper, a new non-isothermal two-phase flow model is presented that improves upon the simulation accuracy and capability of historical reduced drift-flux models (RDFM) while still retaining high computational efficiency. Built on the “no pressure wave” assumption of the RDFM, our new RDFM achieves improvements through calculating the temperature dynamics, considering interface mass transfer (i.e., gas-in-oil solubility behavior), and introducing a new lumped pressure dynamics model. By including these physical factors that are critical for practical applications, the proposed RDFM shows higher simulation accuracy and capability compared to historical RDFMs. The validity of the proposed model is proven by comparing it to field measurements, benchmark models, and the classical drift-flux model. Moreover, the proposed RDFM successfully retains the high computational efficiency of historical RDFMs even with the addition of the aforementioned complex physical dynamics. When conducting full-scale gas influx simulations, the proposed RDFM achieves a computational speed at more than two orders of magnitude faster than real-time. Due to its good performance on both computational efficiency and simulation accuracy, the proposed model is suitable for real-time applications in most well construction scenarios. It is especially superior to historical RDFMs when simulating more complicated but still common scenarios, e.g., deepwater wells drilled in high-pressure high-temperature environments, and wells experiencing gas-in-oil solubility behavior.