The Ultimate Guide To Drilling

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. In this scenario, the material and configuration of the material used in each sealing element may be selected such that those identified for primary use while pulling the drill string out of the wellbore may be constructed of a more abrasion-resistant material than those sealing elements selected for primary use while drilling.
The drilling fluid (mud) of the reverse circulation drilling rig is circulated by using a mud pump from the wellhead of the well (outside the drill pipe) rcd drilling to the well, and then using a compressed air or mud pump to pump out from the middle of the drill pipe, so it is easier to take out slag muck.

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.
When the tool joint has passed through a sealing element and is about to be passed through a second sealing element, the pressures within each cavity may be adjusted again such that the conditions under which the tool joint passed though the first sealing element are replicated for the second sealing element.
When the goal is to achieve the highest-pressure capacity and longest seal life, the rotary seals of an RCD can be mounted in seal carriers that align on the mandrel and move laterally to follow lateral shaft deflection and runout (see here , and here ). Such carriers allow a small extrusion gap clearance to be used for the pressure retaining seals, without risk of seal-damaging metal-to-metal contact at the extrusion gap.

However, the casing shoe pressure integrity may be less than the formation fracture pressure when drilling offshore, such as in geologically young particulate sediments, through salt domes, whose yielding characteristics challenge the ability to obtain an acceptable casing and casing shoe cement job.
Is a multiple broken elevational view of an exemplary embodiment of a land drilling rig showing an RCD positioned above a blowout preventer ("BOP") stack, a cemented casing and casing shoe in partial cut away section, and a drill string extending through a formation into a wellbore.
In CBHP MPD, sometimes there is a 10 choke-closing pressure setting when shutting down the rig mud pumps, and a 10 chokeopening setting when starting them up. The mud weight may be changed occasionally as the well is drilled deeper when circulating with the choke valve open so the well does not flow.

It should be noted that for all situations described above in which the pressures within the cavities are adjusted according to the phase of the drilling operation, or the timing of events, or according to operator selection, the monitoring and adjustment may be accomplished using manual control, using pre-programmed control via one or more PLCs, using programmed control to react to a sensor output (again via a PLC), or by using any combination of these.
A typical land-based MPD operation might represent 10-20% of the overall well cost, he says - at the lower end if it is not implemented through the entire well section, and also depending on whether it is a directional or straight hole, and using oil or water-based fluids.