Abstract: A system for drilling a subsea well from a rig through a subsea wellhead below the rig includes a wellhead stack which is mounted on the subsea wellhead. The wellhead stack includes at least a subsea blowout preventer stack and a subsea diverter. A drill string extends from the rig through the wellhead stack into the well to conduct drilling fluid from the rig to a drill bit in the well. A riser which has one end coupled to the wellhead stack and another end coupled to the rig internally receives the drill string such that a riser annulus is defined between the drill string and the riser. A well annulus extends from the bottom of the well to the subsea diverter to conduct fluid away from the drill bit. A pump has a suction side in communication with the well annulus and a discharge side in communication with the rig and is operable to maintain a selected pressure gradient in the well annulus.

Abstract: A positive-displacement pump includes multiple pumping elements, each pumping element having a pressure vessel with a first and a second chamber and a separating member disposed between the first and second chambers. The first chambers and the second chambers are hydraulically connected to receive and discharge fluid, wherein the separating members move within the pressure vessels in response to pressure differential between the first and second chambers. A valve assembly having suction and discharge valves communicates with the first chambers. The suction and discharge valves are operable to permit fluid to alternately flow into and out of the first chambers. A hydraulic drive alternately supplies hydraulic fluid to and withdraws hydraulic fluid from the second chambers such that the fluid discharged from the first chambers is free of pulsation.

Abstract: The invention provides an improved pipeline pulsation dampener, including a pressure vessel divided by a diaphragm of elastomeric material into first and second pressure zones. The first pressure zone is connected to a pipeline and receives any undesired pressure changes in the pipeline through a first flow passage in the pressure vessel, while the second pressure zone receives a second fluid at a preselected pressure. The diaphragm has a reinforcing insert for bridging the first flow passage to support the diaphragm when the pressure of the second fluid in the second pressure zone exceeds the pressure of the first fluid in the first pressure zone to restrain the diaphragm from extruding through the first flow passage. The reinforcing insert is encased in the elastomeric material of the diaphragm to prevent the insert and the bond between the elastomeric material and the insert from being exposed to the fluid being pumped.

Abstract: A remotely operated actuator for a drill string internal blowout preventer is disclosed. It includes an annular cylinder for mounting on the preventer housing to rotate with the housing and the kelly. An annular piston in the cylinder moves a link pivotally connected to the piston and a crank arm to open and close the preventer.

Abstract: A tubular connection is shown having wedge threads, the individual threads preferably interlocking by having wider crest dimensions than respective root dimensions, but with the stab flanks and load flanks generally angling in the same direction with respect to the longitudinal axis of the connection. Thus, when the stab flank is positive, it is less positive than the load flank is negative. Conversely, when the stab flank is negative, it is more negative than the load flank is positive. Preferably, the roots and crests radially interfere prior to full makeup. The connection achieves distribution over the entire thread length of the bearing stresses that resist torsional makeup, of the torque load, and of sealing. The slant of the flanks achieves self-centering of the pin member with respect to the box member either during assembly or disassembly depending on the angling in the respective embodiments.

Abstract: A connection for and a method of connecting the ends of two joints of low modulus, low hardness, low strength plastic pipe. The connection includes a threaded box on one joint and a threaded pin on the other joint. The box has tapered, internal, generally dovetail-shaped threads with stab flanks and load flanks and flat roots and crests that are parallel to the longitudinal axis of the pipe. The pin has tapered, external, generally dovetail-shaped threads with stab flanks and load flanks and flat roots and crests that are parallel to the longitudinal axis of the pipe for mating with the internal threads of the box. The threads increase in width in one direction on the box and in the other direction on the pin. When the connection is made up the roots, crests, and flanks of the threads move into engagement to form seals that resist the flow of fluids between the threads.

Abstract: A threaded pipe connection is disclosed comprising a box having internal threads and a pin having external threads for mating with the internal threads of the box. The mating threads exert radial forces on the box and pin creating compressive hoop stress in the pin and tensile hoop stress in the box. A conical sealing surface on the pin between the threads and the end of the pin engages conical sealing surface on the box and forms a metal-to-metal seal when the connection is made up. Means are provided for reducing the radial forces exerted by the threads adjacent the conical sealing surfaces to reduce excessive metal-to-metal contact bearing stress and better distribute the remaining stress in the engaging sealing surfaces while maintaining the contact stress required to provide an adequate seal.

Abstract: The same size and weight of tubular products, but in different grades of material, are made for universal connection but with seal areas that differ appropriately for adequate sealing without overstressing the connection members for the pressures encountered where each tubular length is put in service. The angle of the conically tapered seal on all box members is made the same for all grades of the products. The pin member of medium grade is made with an equal length seal area and adjacent contracting area on its forward end. The pin member of lower grade is made with a shorter length seal area than its adjacent contacting area, thereby also placing the seal area further from the pin member distal end. This stiffens the pin member. The pin member of higher grade is made with a longer length seal area than its adjacent contacting area.

Abstract: A resilient seal ring for a tubular connection having an outside periphery that comes to a peak. The peak includes preferably two chamfered sides at respective angles to the axis of the ring that are greater than the adjacent conical surface angle. The crown of the peaked top is preferably flat. The connection includes a rectangular groove in a shallowly tapered conical surface of the pin member, preferably on a forward metal-to-metal sealing surface. The groove is slightly less deep than the seal ring.

Abstract: A tubular connection includes a shallowly tapered conical sealing surface. The areas on the pin member where make up and sealing respectively occur in the various embodiments comprise multiple angles and surface texturing for the purpose of lubricant retention, facilitate burnishing and reduce the propensity for galling in multiple make up and break out situations. The pin taper in each case is slightly less than the box taper. The area on the pin member is textured ahead of the very smooth seal area to retain some thread compound even after repeated makeups of the connection. The area ahead of the sealing area where stabbing contact is made is textured in the 125-250 R.sub.a range while the smooth seal area is textured about 63 R.sub.a to provide a gas tight seal under high pressure and severe conditions of combined loads and thermal shock.

Abstract: A threaded pipe connection is disclosed that has threads the flanks, roots, and crests thereof form thread seals when the connection is made up and that has a seal ring of resilient material that is trapped in a cavity between a groove in either the box or the pin and the thread seals to provide a secondary seal.

Abstract: A tool for installing a corrosion barrier ring into its groove behind the threads of a tapered box end comprises a tapered metallic liner for covering the threads and a suitable mandrel for carrying the ring to its location through the liner. A suitable seating tool may be used for the final seating of the ring in the groove. The tip is notched to permit axial deformation of the ring, but not appreciable radial deformation, so as to allow the ring to be positioned to the location of the groove. The tip of the mandrel is sized to prevent the ring from sliding over the mandrel as the mandrel is pushed through the liner. Rotating the mandrel starts the ring into the groove by straightening out the ring deformations and permits removal of the mandrel and the liner. The seating tool is then subsequently used for the final seating of the ring in its groove. Stacked tip pieces permit adjusting the contour and size of the seating tool tip to accommodate to a variety of ring shapes and sizes.