Ballast deployment apparatus and method for installing and retrieving said apparatus

Abstract

An apparatus for controlled deployment of ballast material onto a subsea location, preferably a subsea structure, comprising at least one chute for conveying said ballast material, said chute having a first end and a second end; at least one buoyancy element associated with the chute such that the chute may assume a generally vertical orientation in the water, supported by said buoyancy element; a support element associated with said chute and adapted for cooperation with an installation weight, said chute second end being adapted for connection to an element associated with the seabed. A method for installation of said apparatus comprising bringing the chute into a generally vertical orientation in the water above said subsea location, lowering portions of said installation weight onto said support element, causing said ballast deployment apparatus to move towards the seabed, until said apparatus has reached a desired depth in the water; connecting said chute second end to said element associated with the seabed; and withdrawing said installation weight from said support element, whereupon deployment of ballast material through said chute may commence.

What is claimed is:  
     
         1 . An apparatus for controlled deployment of ballast material to a subsea location, comprising 
 at least one chute for conveying said ballast material, said chute having a first end and a second end;    at least one buoyancy element associated with the chute such that the chute may assume a generally vertical orientation in the water, supported by said buoyancy element; and    a support element associated with said chute and adapted for cooperation with an installation weight.    
     
     
         2 . The apparatus of  claim 1 , wherein said support element is fixed to the chute interior below the location of said buoyancy elements.  
     
     
         3 . The apparatus of  claim 2 , wherein said support element comprises a grating or similar element which does not prevent the conveyance of said ballast material while supporting the installation weight.  
     
     
         4 . The apparatus of  claim 1 , wherein said ballast elements are located at or near said first end.  
     
     
         5 . The apparatus of  claim 1 , wherein said chute first end has a funnel-shape.  
     
     
         6 . The apparatus of  claim 1 , wherein the chute is associated with at least one buoyancy pipe generally oriented parallel to said chute.  
     
     
         7 . The apparatus of  claim 6 , wherein the buoyancy pipe extends the length of said chute.  
     
     
         8 . The apparatus of  claim 1 , wherein a plurality of chutes are joined by flexible joints.  
     
     
         9 . The apparatus of  claim 8 , wherein said joints are covered by a flexible cladding.  
     
     
         10 . The apparatus of  claim 1 , wherein said chute second end is adapted for connection to an element associated with the seabed.  
     
     
         11 . The apparatus of  claim 10 , wherein said element associated with the seabed is a tether connected to a subsea structure.  
     
     
         12 . The apparatus of  claim 10 , wherein said element associated with the seabed is a separate mooring on the seabed.  
     
     
         13 . A method for installing an apparatus for the controlled deployment of ballast material to a subsea location, said apparatus comprising 
 at least one chute for conveying said ballast material, said chute having a first end and a second end;    at least one buoyancy element associated with the chute such that the chute may assume a generally vertical orientation in the water, supported by said buoyancy element;    a support element associated with said chute and adapted for cooperation with an installation weight. and    said chute second end being adapted for connection to an element associated with the seabed,    said method comprising the steps of:    bringing the chute into a generally vertical orientation in the water above said subsea location, said first end being on or near the surface of the water and said second end pointing towards the subsea location;    lowering portions of said installation weight onto said support element, causing said ballast deployment apparatus to move towards the seabed, until said apparatus has reached a desired depth in the water;—connecting said chute second end to said element associated with the seabed; and    withdrawing said installation weight from said support element,    whereupon deployment of ballast material through said chute may commence.    
     
     
         14 . The method of  claim 13 , wherein said portions of said installation weight is lowered into said chute, onto said support element which is fixed inside the chute.  
     
     
         15 . The method of  claim 14 , wherein said installation weight is lowered into a grating or similar element which does not prevent the conveyance of said ballast material, but supports the installation weight.  
     
     
         16 . The method of  claim 13 , wherein said element associated with the seabed is a tether connected to a subsea structure.  
     
     
         18 . The method of  claim 13 , wherein said element associated with the seabed is a separate mooring on the seabed.