Abstract

This paper presents a case study of how a drilling contractor handled the implementation of Managed Pressure Drilling (MPD) equipment on 4 (four) drilling rigs, with focus on the impact on Well Control equipment and emergency disconnect while performing FMCD (Floating Mud Cap Drilling). The paper considers the effects of the rapid inflow of seawater from the bottom of the riser (water rush-in) during a possible emergency disconnect. Additionally, this paper discusses concerns about the subsea equipment when the drilling fluid level is close to the subsea BOP stack or below the seabed. Such scenarios can expose the drilling riser, riser adaptor, flexible joint, BOP annular preventer, BOP seals and gaskets to an inward-acting pressure differential. Restrictions that this inward-acting differential pressure may impose on the conventional equipment currently aboard the drilling units were taken into consideration to determine the feasibility of FMCD operations. This paper highlights the non-conventional considerations as well as challenges associated with this operation for the offshore drilling industry. Those challenges have also motivated technology innovation such as a reduced-friction, next-generation subsea flexible joint, which will operate equally in conventional or MPD conditions.

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