Subsea installation systems and methods

Abstract

There is disclosed a system comprising a vessel floating in a body of water, a line comprising a first portion connected to the vessel and a second portion in the body of water, a tool connected to the second portion of the line, the tool in the body of water below the vessel, a stationary apparatus connected to the second portion of the line, the stationary apparatus in the body of water below the vessel, and a mechanism on the vessel connected to the first portion of the line, the mechanism adapted to keep the line taut as the vessel heaves up and down.

1 . A system comprising:
 a vessel floating in a body of water;   a line comprising a first portion connected to the vessel and a second portion in the body of water;   a tool connected to the second portion of the line, the tool in the body of water below the vessel;   a stationary apparatus connected to the second portion of the line, the stationary apparatus in the body of water below the vessel; and   a mechanism on the vessel connected to the first portion of the line, the mechanism adapted to keep the line taut as the vessel heaves up and down.   
   
   
       2 . The system of  claim 1 , wherein the stationary apparatus comprises a clump weight. 
   
   
       3 . The system of  claim 1 , wherein the stationary apparatus comprises a clamp attached to a subsea structure above the tool. 
   
   
       4 . The system of  claim 1 , wherein the stationary apparatus comprises a clamp attached to a subsea structure below the tool. 
   
   
       5 . The system of  claim 1 , wherein the tool is adapted to perform work on and/or transport materials for a subsea structure. 
   
   
       6 . The system of  claim 1 , further comprising a buoyancy module above the tool and connected to the second portion of the line. 
   
   
       7 . The system of  claim 1 , further comprising a remotely operated vehicle (ROV), the ROV adapted to work with the tool on a subsea structure. 
   
   
       8 . The system of  claim 1 , wherein the tool comprises buoyancy. 
   
   
       9 . The system of  claim 1 , wherein the line is selected from the group consisting of a rope, a cable, an umbilical, and a wire. 
   
   
       10 . The system of  claim 1 , wherein the tool is adapted to carry vortex induced vibration suppression devices to be installed on a subsea structure. 
   
   
       11 . The system of  claim 1 , wherein the mechanism on the vessel comprises a constant tension winch. 
   
   
       12 . A method of insulating a subsea tool from heave of a surface vessel, comprising:
 connecting the tool to a line connected to the vessel;   connecting a stationary apparatus to the line; and   activating a mechanism on the vessel to keep the line taut as the vessel heaves.   
   
   
       13 . The method of  claim 12 , further comprising connecting the line to a buoyancy module above the tool and below the vessel, wherein the buoyancy is at a sufficient depth so that the buoyancy is not subject to heave. 
   
   
       14 . The method of  claim 12  further comprising installing VIV suppression devices on a subsea structure from the tool. 
   
   
       15 . The method of  claim 12 , further comprising launching an ROV from the vessel to work with the tool. 
   
   
       16 . A system comprising:
 a vessel floating in a body of water;   a line comprising a first portion connected to the vessel and a second portion in the body of water;   a tool connected to the second portion of the line, the tool in the body of water below the vessel;   a subsea structure in the body of water near the second portion of the line; and   a stationary apparatus connected to the second portion of the line and the subsea structure, the stationary apparatus in the body of water below the vessel.   
   
   
       17 . The system of  claim 16 , wherein the stationary apparatus comprises a clamp connected to the second portion of the line and the subsea structure at a location above the tool. 
   
   
       18 . The system of  claim 16 , further comprising a weight connected to the second portion of the line at a location below the tool. 
   
   
       19 . The system of  claim 16 , wherein the stationary apparatus comprises a clamp connected to the second portion of the line and the subsea structure at a location below the tool. 
   
   
       20 . The system of  claim 16 , further comprising at least one buoyancy module connected to the second portion of the line at a location above the tool.