Method and apparatus to effect injection of fluids into a subsea horizontal tree

Abstract

An apparatus for effecting injection of fluids into a subsea horizontal tree includes a fluid injection tree cap having a body with a bore extending therethrough so as to open at one end to a top of the body. An isolation valve is cooperative with the bore of the body so as to open or close fluid flow through the bore. The fluid injection tree cap is connected to the horizontal subsea tree. The horizontal subsea tree has only a single crown plug therein. The bore of the fluid injection tree cap communicates with an annulus of the horizontal subsea tree. The horizontal subsea tree has valving therein so as to selectively direct fluid from the bore of the tree cap to the annulus of the well or to the horizontal subsea tree.

I claim: 
     
         1 . An apparatus comprising:
 a fluid injection tree cap having a body with a bore extending through the body so as to open at one end of said body, said fluid injection tree cap having an isolation valve cooperative with said bore of said body so as to open or close a flow of a fluid through said bore;   a horizontal subsea tree having only a single crown plug therein, said horizontal subsea tree having said fluid injection tree cap affixed to an upper end thereof such that said bore of said fluid injection tree cap communicates with an annulus of said horizontal subsea tree; and   a well connected to said horizontal subsea tree, said well having an annulus, said horizontal subsea tree having valving therein so as to selectively direct fluid from said bore of said tree cap to said annulus of said well or to said horizontal subsea tree.   
     
     
         2 . The apparatus of  claim 1 , said horizontal subsea tree having a tubing hanger positioned in said annulus of said horizontal subsea tree. 
     
     
         3 . The apparatus of  claim 1 , said well being a wellhead, said horizontal subsea tree having a connector at a lower end thereof that is affixed to said well. 
     
     
         4 . The apparatus of  claim 1 , said isolation valve positioned above said body of said fluid injection tree. 
     
     
         5 . The apparatus of  claim 1 , said horizontal subsea tree having a mandrel at the upper end thereof, said fluid injection tree cap being connected by a metal-to-metal seal with said mandrel. 
     
     
         6 . The apparatus of  claim 1 , said annulus of said horizontal subsea tree having a workover valve cooperative therewith so as to allow workover fluids to flow to said bore of said body of said fluid injection tree. 
     
     
         7 . The apparatus of  claim 2 , further comprising:
 a line extending from said well and through said tubing hanger and outwardly of said horizontal subsea tree so as to cause production fluid to flow outwardly of said horizontal subsea tree.   
     
     
         8 . The apparatus of  claim 1 , said valving of said horizontal subsea tree selectively directing fluid from said bore of said tree cap to production tubing extending outwardly of said horizontal subsea tree. 
     
     
         9 . An apparatus comprising:
 a fluid injection tree cap having a body with a bore extending through said body so as to open at one end at a top of said body, said fluid injection tree cap having an isolation valve cooperative with said bore of said body so as to open or close a flow of fluid through said bore; and   a horizontal subsea tree having only a single crown plug therein, said horizontal subsea tree having said fluid injection tree cap affixed to an upper end thereof such that the bore of said fluid injection tree cap communicates with an annulus of said horizontal subsea tree, said horizontal subsea tree having valving therein so as to selectively direct fluid from the bore of the tree cap to an annulus of a well or to the horizontal subsea tree or to production tubing.   
     
     
         10 . The apparatus of  claim 9 , said horizontal subsea tree having a tubing hanger positioned in said annulus of said horizontal subsea tree. 
     
     
         11 . The apparatus of  claim 9 , further comprising:
 a well connected to said horizontal subsea tree, said well having an annulus, said valving of said horizontal subsea tree selectively directing fluid from said bore of said tree cap to the annulus of the well.   
     
     
         12 . The apparatus of  claim 11 , said well having a wellhead, said horizontal subsea tree having a connector at a lower end thereof that is affixed to said wellhead. 
     
     
         13 . The apparatus of  claim 9 , said isolation valve positioned above said body of said fluid injection tree cap. 
     
     
         14 . The apparatus of  claim 9 , said horizontal subsea tree having a mandrel at the upper end thereof, said fluid injection tree cap being connected by a metal-to-metal seal with said mandrel. 
     
     
         15 . A method of effecting injection of fluids into a subsea horizontal tree, the method comprising:
 affixing a fluid injection tree cap onto a mandrel of the horizontal subsea tree;   removing a single crown plug of said horizontal subsea tree so as to expose an annulus flow path;   connecting the fluid injection tree cap to a fluid-delivering pipe; and   opening a valve so that the fluid-delivering pipe flows through a bore in a body of the fluid injection tree cap and into the mandrel of the horizontal subsea tree and then flows into an annulus portion of the horizontal subsea tree.   
     
     
         16 . The method of  claim 15 , further comprising:
 directing fluid from the annulus portion of the horizontal subsea tree into an annulus of a well.   
     
     
         17 . The method of  claim 15 , further comprising:
 directing the fluid from the annulus portion of the horizontal subsea tree to a production side of the horizontal subsea tree.   
     
     
         18 . The method of  claim 15 , further comprising:
 connecting an isolation valve to the fluid injection tree cap and of the fluid-delivering pipe.   
     
     
         19 . The method of  claim 18 , further comprising:
 opening the isolation valve so as to allow fluid to flow from the fluid-delivering pipe into the bore of the fluid injection tree.   
     
     
         20 . The method of  claim 15 , further comprising:
 affixing a tubing hanger into a bore of said horizontal subsea tree.