A containment system and a 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 dome comprises a first dome and a second dome connected to the first dome. The second volume of the second dome is smaller than the first volume of the first dome.

1 . 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, 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:
 dome intended to be secured to the seafloor around the leaking device and forming a cavity, 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 at least one tipper output opening adapted to extract the hydrocarbon fluid for recovering, and   an anti hydrates system that actively prevents or remediates hydrates inside the cavity, and   wherein the dome comprises a first dome having a first volume adapted to receive the leaking device, and a second dome having a second volume smaller than the first volume, the second dome being situated above the first dome, and the first and second volumes being in communication via a dome opening.   
     
     
         2 . The containment system according to  claim 1 , wherein the second volume is smaller than a ¼ th  of the first volume, and preferably smaller than a 1/10 th  of the first volume. 
     
     
         3 . The containment system according to  claim 1 , wherein the second volume is higher than a 1/20 th  of the first volume. 
     
     
         4 . The containment system according to  claim 1 , wherein the dome opening is between 2 and 4 meters wide. 
     
     
         5 . The containment system according to  claim 1 , wherein the first dome is thermally insulated with an insulating material for having an overall heat transfer coefficient of the first dome lower than 1 W.m −2 .K −1 . 
     
     
         6 . The containment system according to  claim 1 , wherein the anti hydrates system is situated into or onto the second dome. 
     
     
         7 . The containment system according to  claim 1 , wherein the anti hydrates system is a heating system for heating at least a portion of the cavity. 
     
     
         8 . The containment system according to  claim 1 , wherein the anti hydrates system is an injection systems that inputs an injection fluid into the cavity. 
     
     
         9 . The containment system according to  claim 8 , wherein the injection system comprises a plurality of output ports spread inside the second volume or at the dome opening, said output ports being fed with the injection fluid. 
     
     
         10 . The containment system according to  claim 8 , further comprising a fluid heater for heating the injection fluid before injection into the cavity. 
     
     
         11 . The containment system according to  claim 8 , wherein the injection fluid comprises one or a combination of the fluid components chosen in 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. 
     
     
         12 . The containment system according to  claim 8 , further comprising a pipe having an inner tube forming an inner channel, and an outer tube surrounding said inner tube and forming an annular channel, and wherein the inner channel is used to extract the hydrocarbon fluid from the upper output opening and the annular channel is used to feed the injection system with at least an injection fluid, or inversely. 
     
     
         13 . A method for using a containment system for recovering hydrocarbon fluid from as leaking device that is situated at the sea floor and that is leaking hydrocarbon fluid from a well, and 
       wherein the containment system comprises:
 as dome forming a cavity under said dome to accumulate hydrocarbon fluid coming upwardly from the leaking device, said dome comprising at least one upper output opening adapted to extract the hydrocarbon fluid for recovering, and 
 an anti hydrates system that actively prevents or remediates hydrates inside the cavity, and 
 
       wherein the dome comprises a first dome having a first volume, and a second dome having a second volume smaller than the first volume, the second dome being situated upper the first dome, and 
       wherein the method comprises the following successive steps:
 a) installing the first dome on the seafloor around the leaking device, the cavity completely surrounding and including the leaking device, 
 b) installing the second dome upper to the first dome so as the first and second volumes are in communication via a dome opening. 
 
     
     
         14 . The method according to  claim 13 , wherein the anti hydrates system is a heating system for heating at least a portion of the cavity. 
     
     
         15 . The method according to  claim 13 , wherein the anti hydrates system is an injection systems that inputs an injection fluid into the cavity. 
     
     
         16 . The method accordion to  claim 15 , wherein the injection system injects the injection fluid into the second volume of the second dome before step b). 
     
     
         17 . The method according to  claim 15 , wherein the injection system injects the injection fluid at a velocity that is low, and preferably at a velocity that is lower than 0.5 meter per seconds. 
     
     
         18 . The method according to  claim 13 , wherein the containment system further comprises a level sensor and an output valve connected to the upper output opening, and wherein the method further comprises the following steps:
 c) measuring by the level sensor an interface level of a fluid interface between hydrocarbon fluid and any other fluid inside the dome,   d) controlling the output valve on the bases of the interface level measured by the level sensor for outputting hydrocarbon fluid from the cavity.   
     
     
         19 . The method according to  claim 18 , wherein at step d), the output valve is controlled so as to keep the interface level lower or equal to a level of output of the hydrocarbon fluid from the leaking device. 
     
     
         20 . The method according to  claim 13 , wherein the containment system further comprises a temperature sensor and an output valve connected to the upper output opening, and wherein the method further comprises the following steps:
 c) measuring by the temperature sensor a temperature of the fluid inside the dome,   d) controlling the output valve on the bases of the temperature measured by the temperature sensor for outputting hydrocarbon fluid from the cavity.