Evaluation of a dual relief well operation

Abstract

The Norwegian petroleum authority initiated a new regulation in 2012. All new wells on the Norwegian shelf originally designed to be killed by two relief wells, in case of a worst case scenario, are rejected. The reason is the lack of experience on killing a well by two relief wells. Internal research on dual relief well drilling has been initiated by some operating companies, but none of the reports are public. This thesis will use experience from established well killers and simulations done on single relief wells to evaluate the procedure of a dual relief well operation. Calculations are performed on sections evaluated as critical in a dual relief well drilling operation and the results have been discussed with experienced well killers from Norway and USA. The thesis will also do sensitivities on single relief well operations to evaluate the possibility of killing a high magnitude blowout with one relief well. The main conclusions drawn from the results of this thesis are that the capacity of a single relief well cannot be enhanced to kill a well that normally require the rates of two relief wells. The dual relief well option focused on in this thesis is considered safer than the other comparing method. The background of this conclusion is primarily literature from single relief wells and through interviews with experienced well killers. The hydraulic differences between the two options are concluded to be fairly equal in this study.Future experiments on the commingling section of the dual relief well method are recommended by the author. By using research on multilateral production wells, great similarities in experiments can be drawn when evaluating the flow regime. Additionally, improved blowout simulation software must be evolved, to handle inflow from two relief wells.