Drilling operation suspension spool

Abstract

A drilling operation suspension spool system which operates to provide a dual sealing barrier for a well during suspension of drilling operations. The system includes a spool having a spool adapted to be secured in fixed relation to a wellhead and a dummy hanger adapted to be matedly inserted into the spool. The dummy hanger includes an annular sleeve and a removable axial plug disposed within the annular sleeve insert. A plurality of extendable and retractable locking pins secure the dummy hanger in place.

1 . A drilling operation suspension spool system for disposition in sealing relation to a wellhead operatively connected to a well, the spool system comprising:
 a spool adapted to be secured in fixed relation to the wellhead, the spool including an axial channel, an upper set of radial locking pin channels extending radially away from the axial channel, a middle set of radial locking pin channels extending radially away from the axial channel, and a lower set of radial locking pin channels extending radially away from the axial channel, the upper, middle and lower sets of radial locking pin channels being axially spaced apart;   a dummy hanger adapted to be matedly inserted into the axial channel, the dummy hanger including an annular sleeve insert having a central bore and a removable axial plug disposed within the central bore of the annular sleeve, the annular sleeve including a locking engagement for aligned relation with the middle set of radial locking pin channels;   an upper set of extendable and retractable locking pins disposed within the upper set of radial locking pin channels, the upper set of extendable and retractable locking pins including distal ends adapted to project to a position radially inward of the central bore of the annular sleeve insert so as to limit upward axial movement of the axial plug;   a middle set of extendable and retractable locking pins disposed within the middle set of radial locking pin channels, the middle set of extendable and retractable locking pins including distal ends adapted to engage the locking engagement of the annular sleeve;   a lower set of extendable and retractable locking pins disposed within the lower set of radial locking pin channels, the lower set of extendable and retractable locking pins including distal ends adapted to project to a position radially inward of the central bore of the annular sleeve;   a first compressible seal disposed circumferentially about the annular sleeve;   a second compressible seal disposed circumferentially about the annular sleeve in axially spaced relation from the first compressible seal;   a third compressible seal disposed circumferentially about the axial plug; and   a fourth compressible seal disposed circumferentially about the axial plug in axially spaced relation from the third compressible seal.   
     
     
         2 . The drilling operation suspension spool system as recited in  claim 1 , wherein the removable axial plug includes a circumferential surface that is slidably inserted in the central bore the annular sleeve. 
     
     
         3 . The drilling operation suspension spool system as recited in  claim 1 , wherein the locking engagement of the annular sleeve includes a groove, and wherein the distal ends of the middle pins are configured to engage the locking engagement by insertion into the groove. 
     
     
         4 . The drilling operation suspension spool system as recited in  claim 1 , wherein an axial distance between the upper and lower sets of locking pins is substantially equal to an axial height of the annular sleeve. 
     
     
         5 . The drilling operation suspension spool system as recited in  claim 1 , wherein the first and second compressible seals are sealed against each of the annular sleeve and the axial channel of the spool. 
     
     
         6 . The drilling operation suspension spool system as recited in  claim 1 , wherein the third and fourth compressible seals are sealed against each of the central bore of the annular sleeve and the mating surface of the removable axial plug. 
     
     
         7 . The drilling operation suspension spool system as recited in  claim 1 , wherein the upper set of extendable and retractable locking pins is disposed above the annular sleeve and the lower set of extendable and retractable pins is disposed below the annular sleeve. 
     
     
         8 . A drilling operation suspension spool system for disposition in sealing relation to a wellhead operatively connected to a hydrocarbon well, the spool system comprising:
 a spool adapted to be secured in fixed relation to the wellhead, the spool including an axial channel, a first set of radial locking pin channels extending radially away from the axial channel, and a second set of radial locking pin channels extending radially away from the axial channel, the first and second sets of radial locking pin channels being axially spaced apart;   a dummy hanger adapted to be matily inserted into the axial channel, the dummy hanger including an annular sleeve insert having a central bore and a removable axial plug having a mating surface, the axial plug being disposed within the central bore of the annular sleeve insert with the mating surface adjacent the central bore, the annular sleeve insert including a locking engagement for aligned relation with the second set of radial locking pin channels;   a first set of extendable and retractable locking pins disposed within the first set of radial locking pin channels, the first set of extendable and retractable locking pins including distal ends adapted to project to a position radially inward of the mating surface of the axial plug so as to limit axial movement of the axial plug;   a second set of extendable and retractable locking pins disposed within the second set of radial locking pin channels, the second set of extendable and retractable locking pins including distal ends adapted to engage the annular sleeve insert;   a first compressible seal disposed circumferentially about the annular sleeve insert;   a second compressible seal disposed circumferentially about the annular sleeve insert in axially spaced relation from the first compressible seal;   a third compressible seal disposed circumferentially about the axial plug; and   a fourth compressible seal disposed circumferentially about the axial plug in axially spaced relation from the third compressible seal.   
     
     
         9 . The drilling operation suspension spool system as recited in  claim 8 , wherein the first set of extendable and retractable locking pins is disposed at a position so as to engage an upper end of axial plug and prevent upward movement of the axial plug. 
     
     
         10 . The drilling operation suspension spool system as recited in  claim 8 , wherein the first set of extendable and retractable locking pins is axially disposed above the annular sleeve. 
     
     
         11 . The drilling operation suspension spool system as recited in  claim 8 , wherein the first and second compressible seals are sealed against each of the annular sleeve and the axial channel of the spool, and the third and fourth compressible seals are sealed against each of the central bore of the annular sleeve and the mating surface of the removable axial plug. 
     
     
         12 . The drilling operation suspension spool system as recited in  claim 8 , wherein the removable axial plug includes a circumferential surface that is slidably inserted in the central bore the annular sleeve. 
     
     
         13 . The drilling operation suspension spool system as recited in  claim 8 , wherein the locking engagement of the annular sleeve includes a groove, and wherein the distal ends of the middle pins are configured to engage the locking engagement by insertion into the groove. 
     
     
         14 . A method of providing a dual seal across a wellhead operatively connected to a hydrocarbon well during suspension drilling operations, the method comprising:
 providing a wellhead;   attaching a drilling operation suspension spool on the wellhead, the spool including an axial channel, a first set of radial locking pin channels extending radially away from the axial channel, a first set of extendable and retractable locking pins disposed within the first set of radial locking pin channels, a second set of radial locking pin channels extending radially away from the axial channel, and a second set of extendable and retractable locking pins disposed within the second set of radial locking pin channels, the first and second sets of radial locking pin channels being axially spaced apart;   landing a dummy hanger in the axial channel of the spool, the dummy hanger including an annular sleeve insert having a central bore and a removable axial plug having a mating surface, the axial plug being disposed within the central bore of the annular sleeve insert with the mating surface adjacent the central bore, the annular sleeve insert including a locking engagement for aligned relation with the second set of radial locking pin channels;   providing a first compressible seal disposed circumferentially about the annular sleeve insert, a second compressible seal disposed circumferentially about the annular sleeve insert in axially spaced relation from the first compressible seal, a third compressible seal disposed circumferentially about the axial plug, and a fourth compressible seal disposed circumferentially about the axial plug in axially spaced relation from the third compressible seal;   extending the second set of locking pins into the axial channel of spool so as to engage the locking engagement of the annular sleeve and fix the annular sleeve within the spool; and   extending the first set of locking pins into the axial channel of the spool so as to position distal ends of the first set locking pins at a position radially inward of the mating surface of the axial plug so as to limit axial movement of the axial plug.   
     
     
         15 . The method as recited in  claim 14 , further comprising inserting an annular bowl in a housing of the wellhead before landing the dummy hanger in the axial channel of the spool. 
     
     
         16 . The method as recited in  claim 15 , further comprising inserting a lower plug in the annular bowl before landing the dummy hanger in the axial channel of the spool. 
     
     
         17 . The method as recited in  claim 16 , further comprising retracting the second set locking pins from the axial channel and from engagement with the annular sleeve into the second set of radial locking pin channels. 
     
     
         18 . The method as recited in  claim 17 , further comprising removing the axial plug from the annular sleeve. 
     
     
         19 . The method as recited in  claim 18 , further comprising removing the lower plug from the annular bowl through the annular sleeve.