Effect of the Spool Cone Angle on the Erosion of a Novel Inner Blowout Preventer

Abstract

This paper presents a novel structure with reliable sealing property for the inner blowout preventer (BOP) device aiming at improving its safety and reliability during drilling process. Namely, the study of effects of flow rate and seat cone angle on the erosion wear rate of inner BOP is performed based on the numerical simulation analyses of inner flow field of inner BOP by means of computational fluid dynamics method with various models including RNG k–e model, discrete phase model and Tabakoff–Grant erosion model. The finite volume method is used for the discrete calculation, and the SIMPLE algorithm is applied for solving the continuity, momentum, energy and turbulent kinetic energy equations. The results reveal that some positions of the valve core are prone to erosion wear, and the optimal angle of the taper angle of the upper and lower valve seats for the inner BOP is 25°. Finally, the static stress analyses and leak tests validate the reliability of the inner BOP. These analyses provide the basis for structural design of the inner BOP.