A containment system and method for using said containment system

Abstract

A containment system for recovering hydrocarbon fluid from a leaking device comprising a dome sealed to the seafloor around the leaking device and forming a cavity for accumulating hydrocarbon fluid. The system comprises a lower closing assembly for closing a lower opening during descent of the system to the seafloor.

1 . A containment system for recovering a hydrocarbon fluid from a leaking device that is situated at the seafloor and that is leaking the hydrocarbon fluid from a well, wherein the containment system is adapted to be landed at the seafloor corresponding to a base level of the containment system, and wherein the containment system comprises:
 a dome intended to be secured to the seafloor around the leaking device and forming a cavity under said dome, said cavity being adapted to completely surround and include the leaking device, and to accumulate hydrocarbon fluid coming upwardly from the leaking device, said dome comprising an upper opening to extract the hydrocarbon fluid for recovery and a lower opening to enter the leaking device inside the cavity,   an upper valve for opening or closing the upper opening, and   a lower closing assembly for closing the lower opening at least during a moving of the containment system from a first location near the sea surface to a second location near the seafloor, and for opening the lower opening when the containment system is being installed around the leaking device.   
     
     
         2 . The containment system according to  claim 1 , wherein the lower opening is between 6 and 12 meters wide, and preferably between 8 and 10 meters wide. 
     
     
         3 . The containment system according to  claim 1 , wherein the dome is thermally insulated with an insulating material for having an overall heat transfer coefficient of the dome lower than 1 W·m −2 ·K −1 . 
     
     
         4 . The containment system according to  claim 1 , wherein the dome comprises a structure that is rigid for building a shape of the dome. 
     
     
         5 . The containment system according to  claim 4 , wherein the structure is composed of interconnected beams. 
     
     
         6 . The containment system according to  claim 4 , wherein the dome comprises an envelope disposed substantially inside the structure and being flexible to adapt itself to the shape of the structure and to seal the cavity. 
     
     
         7 . The containment system according to  claim 6 , wherein the envelope extends below a lower end of the structure to form a flexible lower opening. 
     
     
         8 . The containment system according to  claim 4 , wherein the dome comprises an envelope that extends below a lower end of the structure to form a flexible lower opening. 
     
     
         9 . The containment system according to  claim 7 , wherein the lower closing assembly comprises a narrowing mechanism that is able to close up a lower end of the envelope to close the lower opening. 
     
     
         10 . The containment system according to  claim 1 , wherein the lower closing assembly is a door mechanism articulated to a lower end of the dome and comprising a driving mechanism to close or open the lower opening. 
     
     
         11 . The containment system according to  claim 1 , wherein the lower closing assembly is a diaphragm mechanism positioned at a lower end of the dome and comprising a driving mechanism to close or open the lower opening. 
     
     
         12 . The containment system according to  claim 1 , wherein the lower closing assembly is a door mechanism attached to a lower end of the dome and comprising a driving mechanism to free the door and to open the lower opening. 
     
     
         13 . The containment system according to  claim 1 , wherein the lower closing assembly comprises a flexible membrane, said flexible membrane being adapted for being penetrated by the leaking device when the containment system is moved so as the leaking device enters the cavity. 
     
     
         14 . A method for using a containment system for recovering hydrocarbon fluid from a leaking device that is situated at the seafloor and that is leaking hydrocarbon fluid from a well, said containment system being adapted to be landed at the seafloor corresponding to a base level of the containment system and wherein the containment system comprises:
 a dome intended to be secured to the seafloor around the leaking device and forming a cavity under said dome, said cavity being adapted to completely surround and include the leaking device, and to accumulate hydrocarbon fluid coming upwardly from the leaking device, said dome comprising an upper opening to extract the hydrocarbon fluid for recovering and a lower opening to enter the leaking device inside the cavity,   an upper valve for opening or closing the upper opening, and   a lower closing assembly for closing and opening the lower opening, and   
       wherein the method comprises the following successive steps:
 a) providing a containment system at a first location near sea surface, 
 b) closing the upper valve and the lower closing assembly, and filling the cavity with an anti hydrates fluid, 
 c) moving the containment system from the first location down to a second location near the leaking device, 
 d) connecting a pipe to the upper opening, 
 e) opening the lower opening by the lower closing assembly, 
 f) moving the containment system so as the leaking device enters the cavity, 
 g) opening the upper valve for recovering the hydrocarbon fluid. 
 
     
     
         15 . The method according to  claim 14 , wherein the anti hydrates fluid is heated before the filling step b). 
     
     
         16 . The method according to  claim 14 , wherein the anti hydrates fluid comprises one or a combination of the fluid components chosen from the list of water, salted water, dead oil, an alcohol, an ethanol, a methanol, a glycol, an ethylene glycol, a diethylene glycol, and a low-dosage hydrate inhibitor.