Method and apparatus for making subsea pipe connections

Abstract

A subsea pipeline hub is connected to the hub of an adjacent spool piece connected to an in-place manifold of a subsea structure used in the production of oil and/or gas. The pipeline hub is positioned relative to the opposing spool hub and a remotely operated pipeline connecting tool is lowered from the water's surface to the subsea structure using guidelines and structural guidance for alignment of the pipeline hub with the spool piece hub. The spool piece hub is then drawn to the pipeline hub and the hubs are clamped together by operation of the connecting tool. The seal in the connection can be tested by means of the connecting tool. The spool piece may be retrieved and replaced by the connecting tool if maintenance is needed. Connecting tool operations are powered by hydraulic fluid and controlled from the surface. The pipeline hub may be lowered vertically and pivoted into its position adjacent the spool piece or may be pulled into that position.

Having fully described the nature, operation, advantages and apparatus of our invention we claim:  .[.1. A method for connecting a spool piece hub, connected to a subsea structure manifold, to a fixed pipeline hub aligned for connection to said spool piece hub comprising the steps of: 
     
        means..]. .Iadd.11.  A method for use in connecting and disconnecting a spool piece to and from, respectively, spaced-apart first and second subsea pipes comprising: 1owering a remotely operable pipe connecting-disconnecting tool from the water's surface to said underwater pipes, said tool being capable of latching to and unlatching from two spaced-apart clamp assemblies, one at each end of said spool piece; one of said clamp assemblies being capable of clamping one end of said spool piece to said first subsea pipe and the other of said clamp assemblies being capable of clamping the other end of said spool piece to said second subsea pipe;   guiding said tool onto said first and second subsea pipes, said first subsea pipe being clamped to said one end of said spool piece by means of said one of said clamp assemblies;   moving said other end of said spool piece into engagement with said second subsea pipe by means of said tool; and   operating said other clamp assembly by means of said tool to clamp said other end of said engaged spool piece and said second subsea pipe together. .Iaddend. .Iadd.12. A method as recited in claim 11 including testing at least one of said clamped spool piece connections for leaks. .Iaddend. .Iadd.13. A method as recited in claim 12 including unlatching said tool from said clamp assemblies and retrieving said tool to the water's surface. .Iaddend. .Iadd.14. A method as recited in claim 13 wherein said subsea pipe comprises a pipeline and includes   1owering said pipeline attached to a pivotal trunnion assembly from the water's surface prior to lowering said tool from the water's surface;   guiding said trunnion assembly to a subsea template at said pipe location; and   releasably securing said trunnion assembly to said subsea template, said pipeline being rotated from a vertical position to a horizontal position and into alignment position with said spool piece as additional sections   
     
     
        of pipe are added from a pipelaying vessel. .Iaddend. .Iadd.15.  A method as recited in claim 13 including: 1owering said tool to said underwater location;   guiding said tool onto said first and second subsea pipes;   1atching said tool to each of said clamp assemblies; operating said clamp assemblies by means of said tool to unclamp said engaged first subsea pipe-spool piece and said engaged second subsea pipe-spool piece connections;   disengaging said one end of said spool piece from said first subsea pipe and disengaging said other end of said spool piece from said second subsea pipe by means of said tool; and   raising said spool piece and said clamp assemblies latched thereto to the water's surface by means of said tool. .Iaddend. .Iadd.16. A method as recited in claim 15 including   1owering said tool containing said spool piece and two clamp assmemblies from the water's surface to said underwater location;   guiding said tool onto said first and second subsea pipes;   moving said second subsea pipe into engagement with said other end of said spool and moving said one end of said piece into engagement with said first subsea pipe by means of said tool;   operating said clamp assemblies by means of said tool to clamp said spool piece to said first and second subsea pipes;   testing each of said connections for leaks; and   unlatching said tool from each of said clamp assemblies and retrieving said   
     
     
        tool to the water's surface. .Iaddend. .Iadd.17.  A method as recited in claim 16 in which said first subsea pipe comprises a pipeline and said second subsea pipe comprises a manifold on said subsea template. .Iaddend. .Iadd.18. A method as recited in claim 17 in which said spool piece contains maintainable equipment. .Iaddend. .Iadd.19. A method as recited in claim 18 in which said maintainable equipment comprises a hydraulically operable fail-safe valve. .Iaddend. .Iadd.20. Apparatus for use in connecting and disconnecting a spool piece to and from, respectively, spaced-apart first and second subsea pipes comprising: two clamp assemblies for clamping the ends of said spool piece to the ends of said first and second subsea pipes;   a remotely operable pipe connecting-disconnecting tool including:   guidance means engageable with said second subsea pipe;   1anding means engageable with said first subsea pipes;   means connecting said guidance means and said landing means for moving said spool piece into engagement with said first subsea pipe;   means for engaging one of said clamp assemblies for operating said one clamp assembly to clamp said spool piece and said first subsea pipe together; and   means for releasably latching said tool to each of said clamp assemblies. .Iaddend. .Iadd.21. Apparatus as recited in claim 20 in which said spool piece comprises maintainable equipment. .Iaddend. .Iadd.22. Apparatus as recited in claim 21 in which said maintainable equipment comprises a hydraulically operable fail-safe valve. .Iaddend. .Iadd.23. Apparatus as recited in claim 22 including a hub formed on said second subsea pipe, said guidance means including a yoke for engaging said second subsea pipe hub. .Iaddend. .Iadd.24. Apparatus as recited in claim 23 including:   two spaced-apart adjustable plates for engaging said spool piece, each of said plates containing guide means, wrench means, and motor means for operating said wrench means;   guide sleeves arranged on said clamp assemblies to receive said guide means; and   wrench heads arranged on said clamp assemblies, said wrench means being engageable with said wrench heads. .Iaddend.