BULLHEADING II TWO PHASE SIMULATION OF A DEFINITIVE WELL KILL

Bullheading refers to the pumping or squeezing of fluids into the well against pressure in order to force back the escaped gas into the formation in order to kill the well. However, the main concern in bullheading is that when the gas leaks and goes up to the surface, it may have the potential to cause a blowout. It is common in well killing method but little written information is available in this area. The aim of this research is to determine the factors affecting bullheading through parametric studies. This study is will be focusing on vertical well with five well control parameters which are the killing fluid pressure, velocity, viscosity ration and friction wall of tubing in analyzing the volume fraction of water and pressure drop in the tubing. In the methodology, a base case model is selected which is the internal diameter and length of tubing are 4in and 50in respectively. The simulation will be using two fluids which are fresh water as the killing fluid and natural gas as the escaped gas. Based on the parametric study, the most contributing factors to volume fraction of water are the velocity of killing fluid followed by viscosity ratio. While, pressure of killing fluid and the friction wall of tubing contributes less in volume fraction of water. However, looking in term of pressure drop, viscosity ratio has the highest contribution factor followed by velocity of the killing fluid whereas pressure of killing fluid has the least effect. In conclusion, the four factors shows individual effects on bullheading which will assist in successful well kill.