Systems And Methods For Collecting Hydrocarbons Vented From A Subsea Discharge Site

Abstract

A method for capturing at least a portion of hydrocarbon fluids vented into the surrounding sea from a subsea discharge site comprises (a) mounting a pressure control device to the subsea discharge site. Further, the method comprises (b) flowing the vented hydrocarbon fluids from the subsea discharge site through the pressure control device. Still further, the method comprises (c) positioning a collection system subsea on a lower end of a tubular string. Moreover, the method comprises (d) flowing the vented hydrocarbons fluids from the pressure control device into the collection system and through the tubular siring after (b). The method also comprises (e) minimizing lateral and vertical loads applied to the subsea discharge site by the collection system.

What is claimed is: 
     
         1 . A method for capturing at least a portion of hydrocarbon fluids vented into the surrounding sea from a subsea discharge site the method comprising:
 (a) mounting a pressure control device to the subsea discharge site;   (b) flowing the vented hydrocarbon fluids from the subsea discharge site through the pressure control device;   (c) positioning a collection system subsea on a lower end of a tubular string;   (d) flowing the vented hydrocarbons fluids from the pressure control device into the collection system and through the tubular string after (b); and   (e) minimizing lateral loads applied to the subsea discharge site by the collection system.   
     
     
         2 . The method of  claim 1 , wherein the discharge site is a side outlet of a capping stack coupled to a subsea BOP mounted to a wellhead disposed at the sea floor at an upper end of a wellbore. 
     
     
         3 . The method of  claim 1 , wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit. 
     
     
         4 . The method of  claim 3 , wherein the pressure control device is releasably locked onto the discharge site. 
     
     
         5 . The method of  claim 1 , wherein the collection system comprises:
 a connection member disposed at an upper end of the collection system;   an overshot tool disposed at a lower end of the collection system; and   a flexible conduit extending from the connection member to the overshot tool.   
     
     
         6 . The method of  claim 5 , wherein the overshot tool comprises a rigid tubular having a central axis, a lower end, and an elongate slot extending axially from the lower end. 
     
     
         7 . The method of  claim 5 , wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit;
 wherein (c) further comprises:
 (c1) inserting an outlet end of exhaust conduit into the lower end of the overshot tool; 
 (c2) axially advancing the outlet end of the exhaust conduit into the overshot tool; and 
 (c3) axially advancing the exhaust conduit through the slot during (c2); 
   wherein (d) comprises flowing the vented hydrocarbons fluids from the exhaust conduit through the connection member, the flexible conduit, and the connection member into the tubular string.   
     
     
         8 . The method of  claim 1 , wherein the collection system comprises:
 an overshot tool having a lower end comprising a coupling member and an upper end comprising a stabbing member; and   a connection member hung from a lower end of the tubular string and configured to receive the stabbing member of the overshot tool.   
     
     
         9 . The method of  claim 8 , wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit;
 wherein (c) further comprises:
 (c1) positioning the overshot tool subsea; 
 (c2) inserting an outlet end of exhaust conduit into the coupling member of the overshot tool; 
 (c3) releasably securing the coupling member to the exhaust conduit 
 (c4) positioning the connection member subsea with the tubular string; 
 (c5) inserting the stabbing member of the overshot tool into a lower end of the connection member after (c3); and 
 (c6) axially advancing the stabbing member into the connection member after (c4); 
   wherein (d) comprises flowing the vented hydrocarbons fluids from the exhaust conduit through the overshot tool and the connection member into the tubular string.   
     
     
         10 . The method of  claim 1 , wherein the collection system comprises:
 a connection member hung from a lower end of the tubular string;   a top hat coupled to the connection member;   an annular skirt hung from a lower end of the top hat, wherein the skirt includes a plurality of circumferentially adjacent flexible panels.   
     
     
         11 . The method of  claim 10 , wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit;
 wherein (c) further comprises:
 (c1) positioning the collection system subsea laterally offset from the exhaust conduit; 
 (c2) positioning the collection system subsea until an upper end of the exhaust conduit is axially positioned between the top hat and a lower end of the skirt; 
 (c3) moving the collection system laterally over the upper end of the exhaust conduit; 
 (c4) pushing the flexible panels apart with the upper end of the exhaust conduit during (c3); 
 (c5) positioning the upper end of the exhaust conduit within the skirt; 
   wherein (d) comprises flowing the vented hydrocarbons fluids from the exhaust conduit through the top hat and the connection member into the tubular string.   
     
     
         12 . An assembly for capturing at least a portion of hydrocarbon fluids vented into the surrounding sea from a subsea discharge site, the assembly comprising:
 a collection system including a connection member, an overshot tool, and a flexible conduit extending from the overshot tool to the connection member;   wherein the connection member has a central axis, an upper end, a lower end, and a flow passage extending axially from the upper end to the lower end, the upper end configured to releasably connect to a lower end of a tubular string and the lower end coupled to the flexible conduit;   wherein the overshot tool has a central axis, an upper end coupled to the flexible conduit, a lower end, and a flow passage extending from the lower end of the overshot tool to the upper end of the overshot tool;   wherein the overshot tool includes an elongate slot extending axially from the lower end and extending radially through the overshot tool to the flow passage of the overshot tool;   wherein the flexible conduit is in fluid communication with the flow passage of the overshot tool and the flow passage of the connection member.   
     
     
         13 . The assembly of  claim 12 , wherein the connection member comprises a J-latch coupling having a rigid tubular body, an annular funnel guide at the upper end of the connection member, and a pair of circumferentially spaced J-slots in the e tubular body axially adjacent the funnel guide. 
     
     
         14 . The assembly of  claim 12 , wherein the slot of the overshot tool defines a pair of opposed edges, wherein a resilient bumper is mounted to at least a portion of each edge. 
     
     
         15 . The assembly of  claim 12 , further comprising a pressure control device coupled to the discharge site, wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit;
 wherein the exhaust conduit extends through the slot in the overshot tool, and wherein an outlet end of the exhaust conduit is disposed within the overshot tool.   
     
     
         16 . The assembly of  claim 15 , wherein the pressure control device has a central axis, an upper end, and a lower end;
 wherein the pressure control device comprises:
 an annular receiving guide at the lower end of the pressure control device; 
 a coupling axially adjacent the receiving guide, wherein the coupling is configured to releasably lock onto the discharge site; 
 a tubular fluid conduit extending from the coupling of the pressure control device to an inlet of the choke valve. 
   
     
     
         17 . The assembly of  claim 15 , wherein the coupling of the pressure control device is configured to releasably lock onto a side outlet of a capping stack mounted to a subsea BOP. 
     
     
         18 . An assembly for capturing at least a portion of hydrocarbon fluids vented into the surrounding sea from a subsea discharge site, the assembly comprising:
 a collection system including a connection member and an overshot tool;   wherein the connection member has a central axis, an upper end, a lower end, and a flow passage extending axially from the upper end to the lower end, the upper end configured to releasably connect to a lower end of a tubular string and the lower end comprising a funnel guide;   wherein the overshot tool has a central axis, an upper end, a lower end, a flow passage extending from the lower end of the overshot tool to the upper end of the overshot tool;   wherein the overshot tool includes a coupling member at the lower end of the overshot tool and an elongate stabbing member extending axially from the coupling member to the upper end of the overshot tool;   wherein the stabbing member is slidingly disposed in lire flow passage of lire connection member.   
     
     
         19 . The assembly of  claim 18 , wherein the connection member comprises a J-latch coupling having a rigid tubular body, an annular funnel guide at the upper end of the connection member, and a pair of circumferentially spaced J-slots in the tubular body axially adjacent the funnel guide. 
     
     
         20 . The assembly of  claim 18 , wherein the coupling member includes a plurality of circumferentially spaced locking members, wherein each locking member threadingly engages a bore extending radially through the coupling member and has a first end disposed within the flow passage of the overshot tool and a second end external the coupling member. 
     
     
         21 . The assembly of  claim 18 , further comprising a pressure control device coupled to the discharge site, wherein the pressure control device includes a choke valve having an outlet in fluid communication with an exhaust conduit;
 wherein the outlet end of the exhaust conduit is disposed within the coupling member;   wherein the first end of each locking member engages the exhaust conduit.   
     
     
         22 . The assembly of  claim 21 , wherein the pressure control device has a central axis, an upper end, and a lower end;
 wherein the pressure control device comprises:
 an annular receiving guide at the lower end of the pressure control device; 
 a coupling axially adjacent the receiving guide, wherein the coupling is configured to releasably lock onto the discharge site; 
 a tubular fluid conduit extending from the coupling of the pressure control device to an inlet of the choke valve. 
   
     
     
         23 . The assembly of  claim 22 , wherein the coupling of the pressure control device is configured to releasably lock onto a side outlet of a capping stack mounted to a subsea BOP.