Patent Publication Number: US-11655682-B2

Title: Fluid storage and production

Description:
BACKGROUND 
     Salt caverns, whether naturally occurring or man made are suitable structures for storage of fluids temporarily or permanently. Commonly salt caverns are filled with brine and hence require displacement of the brine in order to use them for fluid storage. Operation that use salt caverns use two separate boreholes into the formation in order to control fluid movement and debrining operations. While this is technically feasible, it lacks efficiency. Therefore, the art would well receive alternative operations that improve efficiency. 
     SUMMARY 
     An embodiment of a flow control assembly including a subassembly including an annular safety valve, a shroud, a bushing connecting the shroud to the subassembly at one of two opposing ends of the shroud, and another bushing connecting the shroud to the subassembly at the other of the two opposing ends of the shroud. 
     An embodiment of a method for operating a hydrogen storage and production system including pumping hydrogen into the salt cavern for storage through a borehole and producing hydrogen from the salt cavern through the same borehole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG.  1    is a cross section view of a flow control assembly as disclosed herein; 
         FIG.  2    is a cross section view of a debrining string configured for use with the flow control assembly of  FIG.  1   ; and 
         FIG.  3    is a view of a wellbore system including the flow control assembly disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Referring to  FIG.  1   , a flow control assembly  10  is illustrated. The assembly  10  includes a tubing subassembly  12  and a shroud  14  that is disposed about the tubing subassembly  12  by multiconnection crossovers  16  at uphole ( 16   a ) and downhole ( 16   b ) ends of the assembly  10 , optionally including control line passthroughs. The crossovers attach a single tubular to multiple nested tubulars as illustrated and are sometime referred to as canfield bushings. One or more control line feedthroughs are contemplated with two illustrated in the uphole bushing  16   a . One of the control lines  20  feeds a ported safety valve nipple  22  such as one commercially available from Baker Hughes by product number H82750. It will be appreciated that the nipple  22  allows hydraulic fluid pressure from line  20  to reach an insert safety valve on a debrining string to be discussed hereunder. The shroud  14  is fluid tight with the subassembly  12  such that an annular fluid space  24  is created between the subassembly  12 , the shroud  14  and the bushings  16 . This annular space  24  is accessible by fluid from radially inwardly of the subassembly  12  through a perforated spacer tube  26 , through which fluid may relatively freely flow between an ID (Inside dimension)  28  of subassembly  12  and the annular space  24 . The space  24  is further accessible through an annular safety valve  30 , which may in some embodiments be or be similar to Baker Hughes product number H73496. Valve  30  is controlled via control line  32 . When the valve  30  is open, fluid may flow through space  24  and when valve  30  is closed, the space  24  is dead headed, thereby preventing fluid flow therethrough. Were the ID  28  occluded in a region between the tube  26  and the valve  30 , flow past the subassembly  12  would occur only if valve  30  were open and would be controllable by the valve  30 . In embodiments, the valve  30  is an annular safety valve as noted above and is a failsafe configuration. Alternate valves could be used such as packers with separate control lines for setting and unsetting, for example. The assembly  10  may be employed in any situation where its attributes are needed. 
     In one situation, the assembly  10  is employed with a debrining string  40 , illustrated in  FIG.  2   . When properly nested together the assembly  10  and debrining string  40  are referred to herein as a debrining and fluid storage system  50 . The string  40  includes an insert safety valve  42 , such as product number H82708 commercially available from Baker Hughes. Valve  42  permits or prevents flow through an ID  44  of the debrining string  40 . String  40  also includes seals  46   a  and  46   b  that straddle the valve  42  and are receivable in a sealing manner in seal bores in or adjacent nipple  22 . The bracket  48  in drawing  FIG.  2    provides for an understanding of the relative positioning when the debrining string  40  is disposed in the assembly  10  to create the debrining and fluid storage system  50 . 
     Referring to  FIGS.  1  and  2    simultaneously, the intent is for the reader to understand that debrining string  40  is to be disposed within subassembly  12  and at the position indicated by the bracket  48 . In this position, there are flow capable structures comprising 1) the ID  44  of the debrining string  40 ,  2 ) a concentric annulus  52  formed between the string  40  and the subassembly  12 , and  3 ) the annular space  24  in the assembly  10  (which space becomes part of a flow path including that space and the concentric annulus  52 . During operation the flow of various fluids is important and is shown via arrows. Arrows  54   a  illustrate flow of fluid uphole and downhole of the seals  46   a  and  b , within the concentric annulus  52  uphole of seal  46   a . Arrows  54   b  illustrated the flow pathway from the concentric annulus  52  through the ported spacer tube  26 , through space  24  and through annular valve  30  back to concentric annulus  52  downhole of seal  46   b . The pathway represented by arrows  54   b  allows for controllability of the concentric annulus flow by interposition of valve  30 . Arrows  56  illustrated a pathway flowing within the ID  44  of string  40 . It should be noted that neither of these paths expose a cemented casing (not shown) that is radially outwardly disposed of the system  50  to any of the fluids being pumped through the assembly  10  in either direction. 
     In one use of the debrining and fluid storage system  50 , the arrows  54  represent a displacing fluid such as CO2 or Hydrogen that is pumped into a salt cavern formation  66  (see  FIG.  3   ). Upon pumping the fluid into the salt cavern  66 , brine within the salt cavern is displaced and flowed along the path of arrows  56  to a remote location such as the surface  62 . Because the flow along  54  and the flow along  56  both include valves, which may be fail safe valves as noted above, the fluid flow in both directions is controlled. This is a requirement for hydrogen operations in some countries. Further, in the case of a hydrogen storage and production system, the hydrogen fluid is segregated from any casing of the wellbore since it is maintained within the concentric annulus  52  both during debrining of the salt cavern and when later using the formation for storage and production of hydrogen, for example. 
     A significant benefit of the construction of system  50  is the removability of string  40  from subassembly  12  while under pressure. It will be appreciated that there are no control lines indicated in  FIG.  2   . There is a safety valve  42  that requires actuation but no line running thereto. This is because the nipple  22  provides the hydraulic pressure from line  20  to the valve  42  when the string  40  is installed in the subassembly  12 . This facilitates removal of string  40  while under pressure through a snubbing unit. In a hydrogen storage and production situation, for example, the ability to remove the debrining string  40  while under pressure enables the operation of a single borehole configuration for the hydrogen storage and production facility. 
     Referring to  FIG.  3   , a wellbore system  58  is schematically illustrated. The system  58  comprises a borehole  60  extending from surface  62  into a subsurface formation  64  leading to a salt cavern  66 . Within the borehole  60  is a string  68  that includes the assembly  10  and may also include the string  40 , which created system  50 . The string  68  extends to the salt cavern  66  in order to convey fluids to and from the salt cavern  66 . A cement casing  70 , whether preexisting or newly created is protected from exposure to the fluid being pumped into the salt cavern  66 , which can be important in the case of Hydrogen. 
     At surface  62  is a snubbing unit  74  to be employed for withdrawing string  40  from string  68  while under pressure, which is the case in a Hydrogen storage and production system. 
     Set forth below are some embodiments of the foregoing disclosure: 
     Embodiment 1: A flow control assembly including a subassembly including an annular safety valve, a shroud, a bushing connecting the shroud to the subassembly at one of two opposing ends of the shroud, and another bushing connecting the shroud to the subassembly at the other of the two opposing ends of the shroud. 
     Embodiment 2: The assembly as in any prior embodiment, further comprising a control line passthrough in one of the bushings. 
     Embodiment 3: The assembly as in any prior embodiment, wherein the subassembly includes a hydraulic passthrough nipple. 
     Embodiment 4: The assembly as in any prior embodiment, wherein the nipple includes a seal bore. 
     Embodiment 5: A debrining and fluid storage system including an assembly as in any prior embodiment, a debrining string having a seal disposed within the assembly. 
     Embodiment 6: The system as in any prior embodiment wherein the debrining string includes a safety valve. 
     Embodiment 7: The system as in any prior embodiment wherein the safety valve is actuated by a hydraulic passthrough nipple in the subassembly. 
     Embodiment 8: The system as in any prior embodiment wherein the debrining string includes two seals straddling the safety valve. 
     Embodiment 9: A debrining and fluid storage system including a borehole in a formation extending to a salt cavern, a string in the borehole, the string including an assembly as in any prior embodiment. 
     Embodiment 10: A system as in any prior embodiment further comprising a debrining string disposed within the assembly. 
     Embodiment 11: A method for debrining a salt cavern including pumping a fluid through an assembly as in any prior embodiment, removing brine from the salt cavern through a debrining string disposed within the assembly. 
     Embodiment 12: The method as in any prior embodiment, further including removing the debrining string from the assembly while under pressure. 
     Embodiment 13: The method as in any prior embodiment further comprising operating a snubbing unit to remove the debrining string. 
     Embodiment 14: The method as in any prior embodiment, further comprising isolating an environment outside of the assembly from Hydrogen. 
     Embodiment 15: The method for operating a hydrogen storage and production system including pumping hydrogen into the salt cavern for storage through a borehole and producing hydrogen from the salt cavern through the same borehole. 
     Embodiment 16: The method as in any prior embodiment wherein the pumping is carried out through a flow control assembly having a subassembly including an annular safety valve, a shroud, a bushing connecting the shroud to the subassembly at one of two opposing ends of the shroud, and another bushing connecting the shroud to the subassembly at the other of the two opposing ends of the shroud. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “about”, “substantially” and “generally” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” and/or “substantially” and/or “generally” can include a range of ±8% or 5%, or 2% of a given value. 
     The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, solution mining, etc. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited.