Apparatus and methods for use in establishing and/or maintaining controlled flow of hydrocarbons during subsea operations

Abstract

Apparatus includes a seal head having first and second ends and a sidewall having an internal diameter. The first end of the seal head is open to the environment, and the second end is closed to the environment by an end cap. The seal head includes an aperture configured to accommodate a subsea source. A tubular seal head extension is fluidly connected to the seal head end cap. The seal head extension has an external diameter, an external surface, and a length. A movable element having first and second ends and a sidewall structure having an internal diameter sufficiently larger than the external diameter of the extension forms an annulus between the movable element and the extension. The movable element first end opens to the environment, while its second end is closed by an end cap defining an exit fluidly connectable to a subsea collection system.

1 . An apparatus comprising:
 a seal head comprising first and second ends and a seal head sidewall structure having an internal diameter, the sidewall structure connecting the first and second ends, the seal head first end open to the environment, the seal head second end closed to the environment by an end cap, the seal head further comprising at least one aperture configured to accommodate a subsea source of hydrocarbons;   a tubular seal head extension fluidly connected to the end cap of the seal head, the tubular seal head extension having an internal diameter less than the internal diameter of the seal head, an external diameter, an external surface, and a length; and   a movable element comprising first and second ends and a sidewall structure having an internal diameter sufficiently larger than the external diameter of the tubular seal head extension to form an annulus there between, the movable element sidewall structure connecting the movable element first and second ends, the movable element first end open to the environment, and the movable element second end closed to the environment by a movable element end cap defining an exit fluidly connectable to a subsea collection system.   
     
     
         2 . The apparatus of  claim 1  wherein the movable element comprises a first end opening configured to slidingly engage the external surface of the tubular seal head extension along its length. 
     
     
         3 . The apparatus of  claim 1  wherein the seal head comprises a second tubular member. 
     
     
         4 . The apparatus of  claim 3  wherein the movable element comprises a third tubular member. 
     
     
         5 . The apparatus of  claim 1  wherein the at least one aperture is in a seal head sidewall structure and is selected from curve-shaped apertures and non-curve-shaped apertures. 
     
     
         6 . The apparatus of  claim 5  wherein the curve-shaped apertures are selected from U-shaped apertures, parabolic apertures, and circular apertures. 
     
     
         7 . The apparatus of  claim 5  wherein the non-curve-shaped apertures are selected from square apertures, triangular apertures, and trapezoidal apertures. 
     
     
         8 . The apparatus of  claim 5  wherein the at least one apertures comprise one or more flexible sealing members. 
     
     
         9 . The apparatus of  claim 2  wherein the external surface of the tubular seal head extension is polished. 
     
     
         10 . The apparatus of  claim 9  wherein the opening of the movable element first end comprises a polished internal surface configured to engage the polished external surface of the tubular seal head extension. 
     
     
         11 . The apparatus of  claim 4  wherein the third tubular is connectable to a drill string. 
     
     
         12 . The apparatus of  claim 2  wherein the movable element first end further comprises a second opening configured to allow material to escape. 
     
     
         13 . The apparatus of  claim 1  further comprising one or more ROV handles attached to the seal head. 
     
     
         14 . The apparatus of  claim 1  further comprising one or more ROV handles attached to the movable element. 
     
     
         15 . The apparatus of  claim 1  wherein the seal head further comprises one or more access points for a functional fluid. 
     
     
         16 . The apparatus of  claim 1  wherein the movable element further comprises one or more access points for a functional fluid. 
     
     
         17 . An apparatus comprising:
 a first tubular comprising first and second ends and a first tubular sidewall structure having an internal diameter, the sidewall structure connecting the first and second ends, the first end of the first tubular open to the environment, the first tubular second end closed to the environment by an end cap, the first tubular comprising at least one aperture in the first tubular sidewall structure configured to accommodate a subsea source of hydrocarbons;   a second tubular fluidly connected to the end cap of the first tubular, the second tubular having an internal [diameter less than the internal diameter of the first tubular, an external diameter, an external surface, and a length; and   a third tubular comprising first and second ends and a sidewall structure having an internal diameter sufficiently larger than the external diameter of the second tubular to form an annulus there between, the third tubular sidewall structure connecting the third tubular first and second ends, the third tubular first end open to the environment, and the third tubular second end closed to the environment by a third tubular end cap defining an exit fluidly connectable to a subsea collection system.   
     
     
         18 . A method comprising:
 deploying a fluid collection apparatus from a surface vessel subsea near a subsea source of hydrocarbons, the apparatus comprising:
 a seal head comprising first and second ends and a seal head sidewall structure having an internal diameter, the sidewall structure connecting the first and second ends, the seal head first end open to the environment, the seal head second end closed to the environment by an end cap, the seal head comprising at least one aperture configured to accommodate a subsea source; 
 a tubular seal head extension fluidly connected to the end cap of the seal head, the tubular seal head extension having an internal diameter less than the internal diameter of the seal head, an external diameter, an external surface, and a length; and 
 a movable element comprising first and second ends and a sidewall structure having an internal diameter sufficiently larger than the external diameter of the tubular seal head extension to form an annulus there between, the movable element sidewall structure connecting the movable element first and second ends, the movable element first end open to the environment, and the movable element second end closed to the environment by a movable element end cap defining an exit fluidly connected to the vessel by a subsea collection system; 
   positioning the apparatus to collect hydrocarbons from the source of hydrocarbons; and   collecting hydrocarbons using the apparatus and the subsea collection system.   
     
     
         19 . A method comprising:
 deploying a subsea collection system and a fluid collection apparatus from a surface vessel subsea near a subsea source of hydrocarbons, the apparatus comprising:
 a seal head comprising first and second ends and a seal head sidewall structure having an internal diameter, the sidewall structure connecting the first and second ends, the seal head first end open to the environment, the seal head second end closed to the environment by an end cap, the seal head comprising at least one aperture configured to accommodate a subsea source of hydrocarbons; 
 a tubular seal head extension fluidly connected to the end cap of the seal head, the tubular seal head extension having an internal diameter less than the internal diameter of the seal head, an external diameter, an external surface, and a length; and 
 a movable element comprising first and second ends and a sidewall structure having an internal diameter sufficiently larger than the external diameter of the tubular seal head extension to form an annulus there between, the movable element sidewall structure connecting the movable element first and second ends, the movable element first end open to the environment, and the movable element second end closed to the environment by a movable element end cap defining an exit fluidly connected to the vessel by the subsea collection system; 
   positioning the apparatus to collect hydrocarbons from the source of hydrocarbons;   displacing seawater from the subsea collection system and the fluid collection apparatus by forcing a low-density gas down the subsea collection system at least during the positioning of the apparatus until the gas bubbles out of a first end of the fluid collection apparatus, limiting ingress of seawater or hydrocarbon gas hydrates into the subsea collection system and apparatus thus limiting plugging of the subsea collection system and apparatus;   moving the surface vessel so that the apparatus is a few meters above the subsea source, with the apparatus in the hydrocarbon plume;   landing the seal head of the fluid collection apparatus on the subsea source, while the apparatus remains filled with low-density gas;   gradually reducing flow of the gas and gradually opening a choke to establish and maintain flow of collected hydrocarbons up the apparatus and subsea collection system.   
     
     
         20 . The method of  claim 19  further comprising pumping a functional fluid into the apparatus through one or more valves on the apparatus during at least the collecting step, limiting hydrocarbon gas hydrate formation during the collecting of hydrocarbons. 
     
     
         21 . The method of  claim 19  further comprising monitoring flow into and out of the first end of the movable element. 
     
     
         22 . The method of  claim 19  further comprising allowing the movable element and attached subsea collection system to move up and down with heave of the surface vessel. 
     
     
         23 . The method of  claim 19  further comprising guiding positioning of the apparatus using one or more ROVs.