Patent ID: 8973674
Filing Date: 2015-03-10
Classification: E21B

Abstract:
1. A drilling system including a drill string which extends from a floating drilling rig to a well bore, and a tubular riser which surrounds at least part of the portion of the drill string between the well bore and drilling rig, the riser having a telescopic joint between a first tubular portion and a second tubular portion of the riser, the first tubular portion extending down to a well head at the top of the well bore and the second tubular portion extending up towards the drilling rig, the telescopic joint comprising an inner tube part which is mounted within an outer tube part, the drilling system further including a riser closure device which is mounted in the second tubular portion of the riser and which is operable to provide a substantially fluid tight seal between the riser and the drill string whilst permitting the drill string to rotate relative to the riser, the riser having a main bore along which the drill string extends, and a side bore which extends from the main bore of the second portion of the riser between the telescopic joint and the riser closure device to the exterior of the riser, to a fluid flow line which extends from the side bore to a fluid reservoir, the fluid flow line being part of a flow control system, wherein the drilling system also includes a damper system which comprises a vessel which is divided into first and second substantially fluid tight chambers by means of a movable divider, the first chamber being connected to the fluid flow line and the second chamber being connected to a pressurized fluid reservoir, and a pressure regulator device which is operable to control the pressure of fluid in the second chamber.