Enhanced Wellhead Clamp Type Hub Connection

Abstract

An apparatus for connecting an upper wellhead member to a lower wellhead member includes a box connector. The box connector has an upper portion that selectively circumscribes the upper wellhead member and a lower portion that selectively circumscribes the lower wellhead member. An adapter plate assembly having an upper adapter ring selectively engages a hub profile of the lower wellhead member, and a separate lower adapter ring selectively engages a generally opposite facing lower hub profile of the lower wellhead member. A plurality of locking dog assemblies drive the adapter plate assembly into engagement with the hub profile and the lower hub profile, the locking dog assemblies being spaced around the box connector.

What is claimed is: 
     
         1 . An apparatus for connecting an upper wellhead member to a lower wellhead member, the apparatus comprising:
 a box connector, the box connector having an upper portion that selectively circumscribes the upper wellhead member and a lower portion that selectively circumscribes the lower wellhead member;   an adapter plate assembly comprising an upper adapter ring that selectively engages a hub profile of the lower wellhead member, and a separate lower adapter ring that selectively engages a generally opposite facing lower hub profile of the lower wellhead member; and   a plurality of locking dog assemblies for driving the adapter plate assembly into engagement with the hub profile and the lower hub profile, the locking dog assemblies being spaced around the box connector.   
     
     
         2 . The apparatus of  claim 1 , wherein certain of the locking dog assemblies engage the upper adapter ring and other of the locking dog assemblies engage the lower adapter ring. 
     
     
         3 . The apparatus of  claim 1 , wherein the locking dog assemblies extend radially through a sidewall of the box connector, the locking dog assemblies having a profile on a radially outward end for actuating the locking dog assemblies. 
     
     
         4 . The apparatus of  claim 1 , wherein the upper adapter ring has a generally upward facing adapter shoulder that engages the hub profile for selectively drawing the upper wellhead member towards the lower wellhead member for setting an annular seal located between the lower wellhead member and the upper wellhead member. 
     
     
         5 . The apparatus of  claim 1 , wherein the locking dog assemblies include an actuation screw and a dog nose located at a radially inner end of the actuation screw that selectively engages and urges one of the adapter rings radially inward, wherein the actuation screw has external threads for mating with internal threads of a bore that extends radially through a sidewall of the box connector. 
     
     
         6 . The apparatus of  claim 1 , wherein the box connector has internal threads on an inner circumference for selective mating with external threads of the upper wellhead member. 
     
     
         7 . The apparatus of  claim 1 , further comprising a retaining member attached to the box connector for selectively retaining the box connector on the upper wellhead member. 
     
     
         8 . An apparatus for connecting an upper wellhead member to a lower wellhead member, the apparatus comprising:
 a box connector, the box connector having an upper portion for selectively circumscribing the upper wellhead member and a lower portion for selectively circumscribing the lower wellhead member;   an annular seal located between the lower wellhead member and the upper wellhead member;   an adapter plate assembly, the adapter plate assembly having an upper adapter ring and a lower adapter ring;   a plurality of upper locking dog assemblies, the upper locking dog assemblies selectively engaging the upper adapter ring to set the annular seal; and   a plurality of lower locking dogs, the lower locking dog assemblies selectively engaging the lower adapter ring.   
     
     
         9 . The apparatus of  claim 8 , wherein the locking dog assemblies extend radially through a sidewall of the box connector, each of the locking dog assemblies having an actuation screw and a dog nose located at a radially inner end of the actuation screw, wherein the actuation screw is threadingly connected to the sidewall of the box connector and the dog nose engages the adapter plate assembly. 
     
     
         10 . The apparatus of  claim 8 , wherein the upper adapter ring has a generally upward facing adapter shoulder that engages a hub profile of the lower wellhead member for selectively drawing the lower wellhead member and upper wellhead member together for setting the annular seal. 
     
     
         11 . The apparatus of  claim 8 , wherein the lower adapter ring has a bottom surface that engages the lower hub profile for selectively transferring a bending moment from the upper wellhead member to the lower wellhead member. 
     
     
         12 . A method for connecting an upper wellhead member to a lower wellhead member, the method comprising:
 disposing an adapter plate assembly on a lower hub profile of the lower wellhead member, the adapter plate assembly having an upper adapter ring and a separate lower adapter ring;   threading a box connector onto an end of the upper wellhead member, the box connector having a plurality of locking dog assemblies spaced around the box connector and extending through a sidewall of the box connector;   landing the upper wellhead member onto the lower wellhead member so that a portion of the box connector circumscribes the lower wellhead member; and   actuating the locking dog assemblies so that an end of each of the locking dog assemblies engage the adapter plate assembly, driving the upper adapter ring and lower adapter ring apart and into engagement with the lower wellhead member.   
     
     
         13 . The method of  claim 12 , wherein the step of driving the upper adapter ring and lower adapter ring apart and into engagement with the lower wellhead member includes driving the upper adapter ring into engagement with a hub profile of the lower wellhead member and driving the lower adapter ring into engagement with the lower hub profile. 
     
     
         14 . The method of  claim 12 , wherein the locking dog assemblies have external threads and the step of actuating the locking dog assemblies includes rotating the locking dog assemblies to move the locking dog assemblies axially inward through the sidewall of the box connector. 
     
     
         15 . The method of  claim 12 , wherein each of the locking dog assemblies include an actuation screw and a dog nose located at a radially inner end of the actuation screw, and wherein the step of actuating the locking dog assemblies includes threading the actuation screw into the sidewall of the box connector so that the dog nose engages the adapter plate assembly. 
     
     
         16 . The method of  claim 12 , wherein the step of actuating the locking dog assemblies includes actuating certain of the locking dog assemblies so that the adapter plate assembly engages a hub profile of the lower wellhead member and actuating other of the locking dog assemblies so that the adapter assembly engages a lower hub profile of the lower wellhead member, the lower hub profile facing in a generally opposite direction than the hub profile. 
     
     
         17 . The method of  claim 12 , further comprising before landing the upper wellhead member onto the lower wellhead member, locating an annular seal between the upper wellhead member and the lower wellhead member. 
     
     
         18 . The method of  claim 17 , wherein the adapter plate assembly has an upper adapter ring and wherein the step of driving the adapter plate assembly into engagement with the upper wellhead member includes driving the upper adapter ring into engagement with a hub profile of the lower wellhead member to energize the annular seal. 
     
     
         19 . The method of  claim 12 , wherein the step of actuating the locking dog assemblies includes driving the adapter plate assembly axially with the locking dog assemblies to energize an annular seal between the upper wellhead member and the lower wellhead member. 
     
     
         20 . The method of  claim 12 , further comprising after threading the box connector onto the end of the upper wellhead member, attaching a retaining member to the box connector, the retaining member engaging the upper wellhead member to prevent relative axial movement between the box connector and the upper wellhead member.