Abstract: A control apparatus for use in controlling the fluid pressure in a borehole during drilling of the borehole, the apparatus including an inlet suitable for connection to a pump, a main outlet suitable for connection to a drill pipe, and an overflow outlet suitable for connection to a fluid reservoir, the inlet being connected to the main outlet by a main flow conduit, and the overflow outlet being connected to the main flow conduit by means of an overflow conduit, wherein the overflow conduit is provided with a pressure regulator by means of which the pressure of fluid in the main flow conduit may be maintained at or around a predetermined pressure value.

Abstract: An assembly of a drill pipe and a connector (10) for connecting a hose (50) to a side-bore (52) of a the drill pipe (54), the drill pipe (54) having a wall (54a) enclosing a main bore (54b), and the side-bore (52) extending through the wall (54a) from the main bore (54b) to the exterior of the drill pipe (54), the connector (10) comprising a hose connector body (12) which forms a first end of the connector (10) which is adapted to be connected to the hose (50), and a drill pipe connector body (14) which forms a second end of the connector (10) which is connected to the drill pipe (54), the connector (10) having an exterior surface and an interior surface which encloses a bore (20, 22) extending from the first end of the connector (10) to a second end of the connector (10), the drill pipe connector body (12) being provided with at least one bayonet connector formation (44) which extends from the exterior surface of the connector (10) generally radially outwardly relative to the bore (20, 22), the bayonet conne

Abstract: A drill pipe (10) having an elongate tubular body (12) with an interior surface enclosing a main bore (14) which extends generally parallel to a longitudinal axis (A) of the tubular body (12) from a first end to a second end of the tubular body (12), a side port (16) provided in an exterior surface of the tubular body (12), a side bore (18) extending through the body (12) from the main bore (14) to the side port (16), and a valve assembly (20, 22) which is operable to substantially prevent flow of fluid along the main bore (14) and to substantially prevent flow of fluid along the side bore (18), wherein the valve assembly (20, 22), side port (16) and side bore (18) are provided in a first connection portion (10a) of the drill pipe (10) at the first end thereof, the first connection portion (10a) comprising a thickened portion of the tubular body (12) in which the separation of the interior surface and the exterior surface is substantially greater than the adjacent portion of the tubular body (12), the length

Abstract: An offshore universal riser system (OURS) and injection system (OURS-IS) inserted into a riser. The OURS/OUR-IS provides a means for pressurizing the marine riser to its maximum pressure capability and easily allows variation of the fluid density in the riser. The OURS-IS includes a riser pup joint with provision for injecting a fluid into the riser with isolation valves. The OURS includes a riser pup joint with an inner riser adapter, a pressure test nipple, a safety device, outlets with valves for diverting the mud flow, nipples with seal bores for accepting RCDs. The easy delivery of fluids to the OURS-IS is described. A method is detailed to manipulate the density in the riser to provide a wide range of operating pressures and densities enabling the concepts of Managed Pressure Drilling, Dual Density Drilling or Dual Gradient Drilling, and Underbalanced Drilling.

Abstract: A method of drilling a subterranean well bore using a tubular drill string, the method including the steps of injecting a drilling fluid into the well bore via the drill string and removing said drilling fluid from an annular space in the well bore around the drill string via a return line, wherein the method further includes oscillating the pressure of the fluid in the annular space in the well bore, and monitoring the rate of flow of fluid along the return line.

Abstract: A drill pipe having a tubular body through which is provided a main bore, a side port provided in an exterior surface of the body, a side bore extending through the body from the main bore to the side port, and a valve member which is movable between a closed position in which fluid flow through the side bore is substantially prevented and an open position in which fluid flow through the side bore is permitted, wherein the movement of the valve member between the closed position and the open position comprises translational movement, and the valve member is located at least predominantly within the side bore.

Abstract: An offshore universal riser system. A riser system includes a valve module which selectively permits and prevents fluid flow through a flow passage extending longitudinally through a riser string. An anchoring device releasably secures the valve module in the flow passage. A method of constructing a riser system includes the steps of installing the valve module in the flow passage, and installing at least one annular seal module in the flow passage. The annular seal module is operative to prevent fluid flow through an annular space between the riser string and a tubular string positioned in the flow passage. Drilling methods include injecting relatively low density fluid compositions into the annular space, and selectively varying a restriction to flow through a subsea choke in a drilling fluid return line. The riser string, including housings for the various modules and external control systems, is dimensioned for installation through a rotary table.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A system for interconnecting a floating rig and a riser assembly includes a rotating control device permitting pressurization of the riser assembly; and a sliding joint connected to the rotating control device, the sliding joint being longitudinally extendable and compressible while the riser assembly is pressurized. Another system includes a sliding joint including more than two telescoping sleeves, and the sliding joint being longitudinally extendable and compressible while the riser assembly is pressurized at the surface. An apparatus includes a sliding joint with multiple sets of telescoping sleeves, each set including at least two of the sleeves. Another apparatus includes a sliding joint with multiple radially overlapping seal assemblies.

Abstract: An offshore universal riser system (OURS) and injection system (OURS-IS) inserted into a riser. The OURS/OUR-IS provides a means for pressurizing the marine riser to its maximum pressure capability and easily allows variation of the fluid density in the riser. The OURS-IS includes a riser pup joint with provision for injecting a fluid into the riser with isolation valves. The OURS includes a riser pup joint with an inner riser adapter, a pressure test nipple, a safety device, outlets with valves for diverting the mud flow, nipples with seal bores for accepting RCDs. The easy delivery of fluids to the OURS-IS is described. A method is detailed to manipulate the density in the riser to provide a wide range of operating pressures and densities enabling the concepts of Managed Pressure Drilling, Dual Density Drilling or Dual Gradient Drilling, and Underbalanced Drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop circulating system for drilling wells has control of the flow rates in and out of the wellbore. Kicks and fluid losses are quickly controlled by adjusting the backpressure. Kick tolerance and tripping margins are eliminated by real-time determination of pore and fracture pressure. The system can incorporate a rotating BOP and can be used with underbalanced drilling.

Abstract: A closed-loop drilling system and method of drilling oil, gas, or geothermal wells is described, whereby through the control of the flow rates in and out of the wellbore, and by adjusting the pressure inside the wellbore by a pressure/flow control device installed on the return line, surface pressure being increased or decreased as required, this in turn decreasing or increasing downhole pressure, occurrence of kicks and fluid losses may be greatly minimized and quickly controlled. Through the method of the invention the elimination of the kick tolerance and tripping margin on the design of the well is made possible, since the pore and fracture pressure will be determined in real-time while drilling the well, and, therefore, nearly no safety margin is necessary when designing the well, reducing significantly the number of casing strings necessary.