Other

Nl Industries

Stanley W Granger

Frode Sveen

Joseph Owen Beard

James J Camerano

An improved annular sealing element for oil well blowout preventers includes a plurality of curved metal segments spaced apart at regular circumferential angles and imbedded in a resilient matrix forming a generally lenticular-shaped body with a hollow central bore. Each segment has a tooth-like upper plate section having a downwardly depending web which is pivotably joined to the upper surface of a wedge-shaped base plate. Pivotability in a vertical plane of the upper plate section relative to the base plate limits the force exertable by the sealing element on a drill string component within the bore of the element. A cylindrical pivot bar formed in the lower surface of the base plate of each segment is adapted to roll or self-pivot on the annular head of a driver piston, thus allowing the sealing element to be installed in existing blowout preventers without modification of the driver piston.

Annular sealing element with self-pivoting inserts for blowout preventers

An improved self-locking piston for use in ram blowout preventers has a hollow cylindrical outer piston which slidably contains an inner locking piston. The inner locking piston has a tapered, frusto-conically shaped front section with a plurality of circumferentially spaced apart, sloping flats formed therein. Apertures provided through the outer wall surface of the main outer piston contain radially slidable driver segments each having a sloping surface complementary to the sloping surface of the flats on the inner piston. Forward motion of the inner piston relative to the outer piston forces the driver segments radially outwards in the apertures. A plurality of locking segments, one each positioned in a groove rearward of and communicating with a separate one of each of the apertures is provided. Each locking segment has a sloping lower front surface adapted to sliding engagement by the sloping upper rear surface of a driver segment. Outward radial motion of the driver segments causes the locking segments to move into locking engagement with an annular groove provided in the inner wall surface of the ram cylinder. Each rear locking segment groove is longer than that of the rear portion of a locking segment. Thus, locking segments may move rearward in their grooves, permitting forward motion of the inner piston, outer piston, piston rod, and ram sealing element to compensate for ram rubber wear while still maintaining the ram sealing element firmly locked in its forward-most sealing position.

Self-adjusting automatic locking piston for RAM blowout preventers

An improved sealing device for variable bore ram blowout preventers of the type that uses a pair of opposed semi-cylindrical ram blocks to urge a pair of resilient sealing elements into sealing circumferential contact with the circumferential surface of a tubular drill string component includes a generally uniform thickness sealing member having in plan view the shape of a semi-circular arch with co-linear rectangular legs which protrude laterally outwards from opposite base ends of the arch. The sealing device includes two identical sealing members, each of which has a plurality of laterally spaced apart metal inserts molded into a resilient matrix. Each insert has a pair of generally flat and parallel upper and lower plates joined by a pedestal disposed perpendicularly between the plates. Five inserts are used; two identical, generally square cross-section end inserts, one each located near the outer lateral end of each leg, two identical, trapezoidal cross-section corner inserts, one each laterally inward of each end insert, and a semi-annular cross-section center arch insert within the center arch section, adjacent the corner inserts. Forcible contact of the front face of each sealing member with a tubular component causes the corners inserts to move laterally away from the end inserts and toward the center insert, thereby forming an effective seal with tubular components of various diameters.

Variable bore ram rubber with non-overlapping inserts

An improved annular sealing element for oil well blowout preventers includes a plurality of curved metal segments spaced apart at regular circumferential angles and imbedded in a resilient matrix forming a generally lenticular-shaped body with a hollow central bore. Each segment has a tooth-like upper plate section which has a convex upper, outer surface adapted to slide upwards on the concavely curved inner wall surface of a blowout preventer cavity. Each upper tooth-like plate section has a downwardly depending web which is vertically pivotably supported within a groove formed in the upper surface of a wedge-shaped base plate at the bottom of the lenticular body. The inner toe portion of each base plate is imbedded in the resilient matrix, while the rear, heel portion of each base plate, which has a convexly curved lower surface, protrudes through the matrix. Pivotability of the upper portion of each segment relative to the base plate limits the force exertable by the element on a drill string component. Upward pivotal motion of the heel portion of the base plate feeds resilient material upwards and radially inwards to compensate for wear of resilient material in the vicinity of the bore walls.

Force-limiting/wear compensating annular sealing element for blowout

An improved sealing element for variable bore ram blowout preventers of the type using two semicircular ram blocks to urge a resilient sealing member into sealing circumferential contact with the circumferential surface of a tubular drill string component includes a generally uniform thickness member having in plan view the shape of a semi-circular arch with bar-shaped legs extending laterally outwards from opposite base ends of the arch. A plurality of metal inserts forms a skeletal structure around which is molded a rubber matrix to form the sealing member. Each insert has a pair of generally flat and parallel upper and lower plates joined together by a pedestal and interleaved with and slidable with respect to the plates of an adjacent insert. Two outer generally rectangular plan-view end inserts have inner lateral edges which slidably interleave with the two outer elongated rectangular lateral ends of each of two intermediate corner inserts. Each of the two corner inserts has an arcuate inner end which slidably interleaves with opposite ends of a single arcuate center insert. The pedestals joining the upper and lower halves of the two corner inserts, and the pedestal joining upper and lower halves of the center insert, each have different tear-drop shaped cross-sectional shapes which promote rubber flow into the sealing area when the seal is compressed.

Variable bore ram rubber

An oil well blowout preventer has a housing with axially aligned entrance and exit pipe casing bores and a coaxially aligned hemispherical cavity in the upper portion of the housing. A ring-shaped, convex upper surface sealing member fits conformally within the hemispherical cavity and is drivable upwards by a hollow, hydraulically actuated piston coaxially encompassing the lower exit bore of the housing. The upper annular surface of the piston is beveled downwards and inwards to mate with the bottom annular surface of the sealing member. The sealing member is comprised of incompressible, tooth-like elements imbedded in a resilient matrix. Force limiting means in the sealing member prevent damagingly large radial impact forces of the teeth-like elements with drill string components disposed longitudinally within the device. In one embodiment, resilient material is interposed between the actuating piston and the incompressible element to limit impact force. In another embodiment, the incompressible element of the sealing member are made up of parts movable with respect to one another, to limit impact force.

Blowout preventer with radial force limiter

An improved blowout preventer of the ram type is provided with means allowing limited relative rotational movement of support elements in the seal along with radial inwardly directed movement of the ram assembly to conform to drill string size and accommodate for a tighter seal thereby enabling support of heavier drill string assemblies of smaller diameter pipe.

Variable ram seal for blowout preventers

A shear ram-type blowout preventer for severing and sealing a drill pipe string comprises a housing having a throughway for receipt of the drill pipe. Opposed first and second ram assemblies are mounted in the housing on opposite sides of the throughway for reciprocation laterally inwardly and outwardly. Each of the ram assemblies comprises a carrier connected to a drive member for effecting such reciprocation, and a ram block carried on the laterally inward side of the carrier. The maximum thickness of the block is generally equal to the maximum thickness of the carrier measured longitudinally of the throughway. The first ram assembly comprises a blade member carried on the ram block and including a cutting portion extending generally laterally inwardly and a mounting shank extending generally upwardly from the cutting portion. The shank is attached to the ram block by generally horizontally disposed pins. The ram block of the second ram assembly defines a recess opening laterally inwardly for receipt of the blade, and the seal of the second ram assembly comprises a blade sealing element facing longitudinally into said recess. The second ram assembly further comprises a seal actuator for actuating the blade sealing element. The blade sealing element and actuator have opposed, longitudinally facing support surfaces, the support surface of the blade sealing element being defined by a laterally outermost rigid support portion thereof, bonded to a laterally innermost deformable sealing portion. The carrier of the second ram assembly may alternatively mount a pipe ram assembly.

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Diamond Bar, CA, United States of America

Stanley W Granger