Solution mining to refloat and dispose of an offshore floating structure

Abstract

An improved fixed ballast for a floating offshore structure. The material used for the ballast may be a dense liquid that is pumped into the fixed ballast tank during ballasting and forced out of the tank during deballasting. The material may also be a soluble material that is ground up into particles and added to water. After a saturated solution is obtained, more particles are added to produce a slurry. The slurry is delivered into the ballast tanks. Removal of the slurry is accomplished by pumping sea water into the ballast tanks until all of the ballast material is dissolved and forced out of the tank.

1 . In a floating offshore structure having a ballast tank that receives fixed ballast, an improved fixed ballast material, said fixed ballast material comprising a slurry formed from a water soluble material that is benign to the environment.  
   
   
       2 . A method for removing the slurry fixed ballast of  claim 1 , comprising pumping water into the ballast tank containing the slurry until the material has been dissolved and removed from the ballast tank.  
   
   
       3 . In a floating offshore structure having a ballast tank that receives fixed ballast, an improved fixed ballast material, said fixed ballast material comprising a liquid that is denser than water and benign to the environment.  
   
   
       4 . A method for removing the dense liquid ballast of  claim 3 , comprising pumping compressed air into the ballast tank to force the liquid from the ballast tank.  
   
   
       5 . A method for removing the dense liquid ballast of  claim 3 , comprising pumping water into the ballast tank to force the liquid from the ballast tank.  
   
   
       6 . A method for adding fixed ballast to a floating offshore structure, comprising: 
 a. dissolving a water soluble material in water to form a saturated solution;    b. forming a slurry by adding additional water soluble material to the saturated solution;    c. pumping the slurry into a ballast tank in the floating offshore structure; and    d. allowing suspended slurry material to settle in the ballast tank.    
   
   
       7 . A method for adding fixed ballast to a floating offshore structure, comprising pumping a liquid that is denser than water and benign to the environment into a ballast tank in the floating offshore structure.  
   
   
       8 . The improved ballast material of  claim 1 , comprising calcium chloride.  
   
   
       9 . The improved ballast material of  claim 3 , comprising cesium formate.