Modeling Gas Migration During a Gas Kick

Abstract

Gas kick is an undesirable problem in the drilling process, which can potentially lead to a blowout. The primary intent of this study is to highlight gas migration and its effect on gas kick mitigation approaches that would benefit the drilling process. The integrated analysis provides valuable insight regarding parameters promoting efficient drilling processes, minimizing the risk of gas kicks. This study aimed to investigate the impact of critical parameters on gas migration during the gas kick in both water-based mud and oil-based mud and to promote an understanding of the dynamics of choke pressure, gas velocity, and bottomhole pressure based on completion and reservoir parameters. This study reveals various factors affecting gas migration during gas kicks, characterized by different interactive parameters. These parameters include wellbore configuration, mud density, kick volume, drill-pipe size, reservoir temperature, and oil-water ratios. A commercial multiphase dynamic well control simulator was used in this study to develop two base models: Oil-Based mud (OBM) and Water-Based mud (WBM). The models were used to perform several parametric studies to investigate the impact of critical parameters on gas migration during the gas kick. Each type of mud acted differently and affected the gas migration discussed in this study. The study explicitly illustrates the different outcomes for each model during gas migration. The parameters that range from most effective to least effective on gas migration are wellbore configuration, kick volume, drill-pipe size, mud density, and reservoir temperature in WBM, while in the OBM, the parameters that range from most effective to least effective are wellbore configuration, kick volume, drill-pipe size, oil-water ratio, mud density, and reservoir temperature. However, the main differences are the gas rise velocity and time in the base models. In water-based mud, the gas velocity is 97.8 ft/min, while the gas velocity in oil-based mud is 75.6 ft/min. The gas is discharged from the well within 48.2 minutes in the water-based mud, while the oil-based mud takes 115.7 minutes.