Two-phase Simulation of Well Control Methods for Gas Kicks in Case of Water and Oil-based Muds

Abstract

Kick occurrence is a possible event during a drilling process. It is required to be handled immediately using a well control method to avoid blowout, financial losses and damages to the drilling crew. Several methods including driller, wait and weight, and concurrent are applicable in the drilling industry to control a well during a kick incident. In this study, typical well control methods were simulated for both cases of water and oil-based muds, and essential parameters such as the required time were calculated. Additionally, for each well control approach, a mathematical algorithm was proposed to simulate the process. In case of oil-based mud, the flash calculation was utilized in each depth and time by considering the effect of kick fluid dissolution in drilling mud to improve the accuracy of control parameters. Based on the results, when oil-based mud is used for drilling, extra time is required to control the well due to kick fluid dissolution in the mud and extensive changes in the mud density. In order to improve the accuracy of the calculations, critical parameters including temperature changes in the well column, dynamic drilling hydraulics, and pressure drop were considered during a well control process. In addition, the simulation of the concurrent method is one of the study innovations because of mud density alternations especially when the mud becomes heavier by a non-linear or complicated mathematical function during the process.