Seals Used For Rotating Control Device (RCD) Applications

A managed pressure drilling system, used in conjunction with a continuous circulating device to control wellbore pressure, helped an international E&P company successfully drill a difficult section of an deepwater exploration well in Ghana, West Africa, in 2012. Applying the above EMW equation, the operator navigates generally within a shifting drilling window, defined by the pore pressure and fracture pressure of the formation, by swapping surface backpressure, for when the pumps are off and the AFP is eliminated, to achieve CBHP.
This would be the case if one or more additional sealing elements within the RCD were to be employed as a "reserve" or protected sealing element, reverse circulation drilling ready to be used as the new "main or sacrificial" sealing element should the original "main or sacrificial" sealing element fail.

Supplying a predetermined fluid pressure in a second cavity defined by the rotating control device inner member, the rotating control device second sealing element and the rotating control device third sealing element when said second sealing element and said third sealing element are sealed on the tubular.
Is a cut away section elevational view of an RCD with one active sealing element and two passive sealing elements, sensors for measuring pressures and temperatures in the diverter housing and into the RCD upper and lower internal cavities, upper and lower RCD internal cavity pressure regulators, and influent and effluent lines for communicating cavity fluid into, in and out of each RCD internal cavity.
Is a cut away section elevational view of an RCD with two passive sealing elements above an independent active sealing element, sensors for measuring pressures and temperatures in the diverter housing and the RCD internal cavities, upper and lower RCD internal cavity pressure regulators, sized ports in the RCD bearing assembly for communicating cavity fluid with each RCD internal cavity.

In future it may be appropriate to promote a system where increased industry access to MPD capabilities would be driven by mandates set by local and international governing bodies as part of their assessment of applications for deepwater drilling permits.
This integration allows for the installation of a managed pressure drilling (MPD) system that monitors mass flow (flow into and out of the well), providing precise early detection of a hazard, and introduces a means to employ swift preventative measures before a situation escalates into a potentially catastrophic scenario.
An operator may not wish to place such a demand on any one sealing element for a prolonged period, and therefore may periodically choose to adjust the pressures within the cavities of the RCD such that other sealing elements within the RCD are utilized as the "main or sacrificial" sealing element, even though the integrity of the original "main" sealing element may still be good.

Would result in a drilling program that ultimately exceeds budget (known in the art as authorization for expenditure "AFE") due to extra casing sizes, extra casing strings, and non-productive time dealing with the loss portion of the kick-loss hazards, such as differential sticking of the drill string with potential twisting and severing of the string, loss of circulation with attendant drilling fluid cost, and well control issues.
Is a cut away section elevational view of an RCD with four passive sealing elements, sensors for measuring pressures and temperatures in the diverter housing and the three RCD internal cavities, three RCD internal cavity pressure regulators and sized ports in the RCD bearing assembly for communicating cavity fluid with each RCD internal cavity.