Improved gas influx distribution estimation using interfacial area transport equation (IATE) enabled two-fluid model: An advanced modeling and full-scale experimental study

Abstract

Gas influx management is a critical aspect of petroleum drilling operations, which aims to prevent the uncontrolled outflow of formation gas and the potential consequences caused by blowouts. This study investigates the distribution of gas influx and the interfacial area concentration (IAC) during gas influx circulation operations through a combination of full-scale experiments and advanced numerical simulations.Experiments were conducted to simulate downhole gas influxes by injecting Nitrogen gas into the base of a 5,160-foot-deep experimental wellbore, which was filled with water. A Distributed Fiber-Optic Sensing (DFOS) system was installed in the wellbore to obtain high-resolution acoustic and temperature data and monitor the gas influx behaviors when circulated out of the annulus. Various types of measurements were obtained to analyze the gas influx length, slip velocities, void fraction distribution, and dispersion behaviors. In addition, an advanced numerical simulator was developed based on a modified Two-Fluid Model and the Interfacial Area Transport Equation (IATE) to simulate the gas influx behaviors. The model estimations were compared to the experimental measurements for validation of accuracy and further insights.The numerical modeling framework, based on the interfacial area transport equation, effectively captured bubble interactions, including mechanisms including bubble breakage and coalescence, by estimating the interfacial area distribution. The gas influx dispersion during circulation was analyzed using both model estimations and experimental data. Good agreement was observed between the model predictions and experimental data, including multi-depths gauge measurements and the DFOS data.This is a novel application of the IATE in well-scale multiphase flow simulations, which has proved to be an effective tool for predicting the dynamics of gas influx distributions. The outcomes of this study provide critical insights into the design and optimization of gas influx management during Managed Pressure Drilling (MPD).