BOP Pressure and Flowrate Conditions During High Pressure Gas Kick Control

Vertical upward multiphase flow through a blowout preventer (BOP) during a gas kick event produces complex fluid flow transients. Further complicating these transients is the fluid phase interactions during BOP closing event. The resultant pressure and flowrate transients are critical parameters that influence the BOP design and should be used to estimate if the BOP can close-on/control a kick event. In this paper, a hydro-mechanical two-phase flow model is developed to predict the fluid pressure and flowrate conditions for fully open and closing BOP during a gas kick. The case of a 20,000 psi reservoir is investigated along with a wel depth, from the rig floor to the borehole, ranging from 10,000 ft to 20,000 ft. The results illuminate the dependence of model-based BOP pressure rated design on the formation productivity index during a gas kick event. Furthermore, using a model-based approach for determining such information is essential in the development of next generation pressure control equipment standards and equipment certification, risk minimization to drilling crew and rig assets and reduction of well intervention frequency. High pressure definition based on pore pressure and/or BOP rated working pressure are discussed as well.