Annular blowout preventer packing element

Abstract

An annular blowout preventer (BOP) packing element with improved sealing function and reduced elastomer loss over time is provided. The annular BOP packing element has a bore formed therethrough and includes an elastomer, an array of hardened segments, and an energizer/extrusion ring. The hardened segments are arranged circumferentially about a longitudinal axis of the packing element and bonded to an upper surface of the elastomer. The energizer/extrusion ring is bonded to a lower portion of the elastomer opposite the upper surface of the elastomer.

1 . An annular blowout preventer (BOP) packing element having a bore formed therethrough, comprising:
 an elastomer;   an array of hardened segments arranged circumferentially about a longitudinal axis of the packing element and bonded to an upper surface of the elastomer; and   an energizer/extrusion ring bonded to a lower portion of the elastomer opposite the upper surface of the elastomer, wherein the energizer/extrusion ring is a single annular shaped piece of material that circumferentially surrounds the bore through the BOP packing element.   
     
     
         2 . The annular BOP packing element of  claim 1 , wherein each of the hardened segments comprises a segment tip at its upper end, wherein a radially inner edge of each segment tip defines an upper portion of the bore though the packing element. 
     
     
         3 . The annular BOP packing element of  claim 1 , wherein each of the hardened segments comprises a vertical height that is less than a vertical distance from a lower surface of the elastomer to an upper surface of the hardened segment. 
     
     
         4 . The annular BOP packing element of  claim 1 , wherein each of the hardened segments comprises a body portion extending into the elastomer and a flange portion resting atop the elastomer. 
     
     
         5 . The annular BOP packing element of  claim 4 , wherein the flange portion comprises a base defining a lower edge of the hardened segment and a tip defining an upper edge of the hardened segment. 
     
     
         6 . The annular BOP packing element of  claim 5 , wherein the flange portion is wider in a circumferential direction at the base than at the tip. 
     
     
         7 . The annular BOP packing element of  claim 4 , wherein the body portion comprises a wall defined by two edges extending at different angles from the flange portion into the elastomer, wherein the two edges intersect at a point. 
     
     
         8 . The annular BOP packing element of  claim 7 , wherein the point at which the two edges intersect is located closer in a radial direction to the bore of the packing element than to a radially outer edge of the packing element. 
     
     
         9 . The annular BOP packing element of  claim 1 , wherein the packing element is a spherical packing element and each of the hardened segments has a rounded upper surface. 
     
     
         10 . The annular BOP packing element of  claim 1 , wherein the ring comprises an annular body portion having an annular shape with an inner diameter and an outer diameter, wherein the inner diameter of the annular body portion partially defines the bore of the packing element, and a plurality of fingers extending radially outward from the outer diameter of the annular body portion. 
     
     
         11 . The annular BOP packing element of  claim 10 , wherein each of the fingers is aligned in a radial direction with a corresponding one of the hardened segments. 
     
     
         12 . The annular BOP packing element of  claim 1 , wherein the elastomer comprises a bore formed therethough that forms a portion of the bore of the packing element, wherein, before the elastomer is compressed, the bore of the elastomer has a first diameter along an upper portion of the elastomer and a second diameter at the lower portion of the elastomer directly adjacent an upper surface of the ring bonded to the elastomer, wherein the second diameter is larger than the first diameter. 
     
     
         13 . The annular BOP packing element of  claim 1 , wherein along a portion of the elastomer forming the bore of the packing element, the elastomer has a circumferential profile defined by a plurality of crests and troughs, wherein the elastomer slopes downward from each crest toward two adjacent troughs. 
     
     
         14 . The annular BOP packing element of  claim 1 , wherein the hardened segments are shaped such that, upon actuation of the packing element, the plurality of hardened segments engage a tubular disposed through the bore of the packing element before the elastomer is compressed into engagement with the tubular. 
     
     
         15 . A method, comprising:
 locking and sealing a tubular within an annular blowout preventer (BOP) via a packing element of the annular BOP, wherein the packing element comprises:
 an elastomer; 
 an array of hardened segments arranged circumferentially about a longitudinal axis of the packing element and bonded to an upper surface of the elastomer; and 
 an energizer/extrusion ring bonded to a lower portion of the elastomer opposite the upper surface of the elastomer, wherein the energizer/extrusion ring is a single annular shaped piece of material that circumferentially surrounds the bore through the BOP packing element. 
   
     
     
         16 . The method of  claim 15 , wherein locking and sealing the tubular comprises:
 closing tips of the plurality of hardened segments in a radially inward direction until the tips contact and close against the tubular; and   after closing the tips, contacting the tubular via the elastomer in a radially collapsed state.   
     
     
         17 . The method of  claim 16 , further comprising transmitting an upward force from a piston of the annular BOP through the energizer/extrusion ring to close the tips of the plurality of hardened segments, wherein the energizer/extrusion ring comprises a plurality of radially extending fingers each disposed beneath a corresponding one of the plurality of hardened segments. 
     
     
         18 . The method of  claim 15 , further comprising preventing extrusion of the elastomer into a space along a bore of the BOP between the packing element and a piston, via the energizer/extrusion ring. 
     
     
         19 . The method of  claim 18 , wherein the elastomer comprises a bore formed therethough, wherein, before the elastomer is compressed, the bore of the elastomer has a first diameter along an upper portion of the elastomer and a second diameter at the lower portion of the elastomer directly adjacent an upper surface of the ring bonded to the elastomer, wherein the second diameter is larger than the first diameter. 
     
     
         20 . The method of  claim 15 , wherein each of the hardened segments comprises a segment tip at its upper end, wherein a radially inner edge of each segment tip defines an upper portion of a bore though the packing element.