Application of Numerical Simulation Technique to the Study of Well Killing While Drilling Mud Has Completely Erupted Out from Borehole

Abstract

To kill blowout wells from which all drilling mud has blown out needs some specific knowledge and understanding of how to determine and plan relevant parameters related to a successful killing job. A comprehensive model is developed to characterize the cocurrent flow of gas/liquid and dynamic pressure response within borehole, and investigate the complete kill procedures and the necessary conditions leading to a successful kill operation under any given blowout conditions. The model is composed of a set of equations with respect to gas/mud transient flow natures, gas influx and pressure balance relationships. Based on the theoretical model, a computer program was constituted by solution of the appropriate equations with numerical method, which is currently capable of simulating the complete empty hole blowout process and showing the typical values and results for development and variations of the fluids distribution, flow rate, fluid density and pressure profile along wellbore. Simulation results indicate that for any given empty hole blowout situations, there is a certain parameter combination region associated with the allowed annular pressure, injection rates and kill mud densities. If the planed kill parameter combination does not fall into such a region a blowing well is impossible to be killed.