Abstract:
An annular blowout container (ABOC) that may be used in multiples in a stack in conjunction with additional gate and shear valves to protect a wellhead. The ABOC incorporates a cylindrical formed bladder that provides a tight constrictive seal around whatever pipe or tubing may be in the well bore. The bladder is made of top and bottom rotator plates with springs extending between the plates. The springs are encased in Teflon® and held in place by Kevlar® then covered over completely with cured Viton® that is injected to complete the overall bladder in a molded form. Rotation of the top and bottom rotator plates effects a twisting constriction around the drill pipe or tubing. Electrical and hydraulic operational components are housed inside chambers within the ABOC for predominantly self-contained operation. The cylindrical bladder assembly may be removed and replaced after extended use.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit under Title 35 United States Code §119(e) of U.S. Provisional Application 61/765,895 filed Feb. 18, 2013 the full disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to valves, and more particularly, but not by way of limitation, to a constriction valve for controlling the flow of fluids from a well, especially during uncontrolled well blowouts. The present invention more specifically relates to devices for constricting around and closing off the annular flow volume surrounding a pipe or tubing present in a well. The present invention may therefore be described as an annular blowout container (ABOC) and therefore relates to an improved constriction valve for controlling the flow of drilling fluids and hydrocarbon fluids and gases in a state of free flow known as blowout in drilling and production phases, in combination with additional valves that may be positioned at the well head. 
     2. Description of the Related Art 
     The control and containment of free flowing fluids, hydrocarbon fluids and gases in well drilling and production operations is critical. There are a wide variety of blowout preventers (BOPS) but these have a long history of failure. In particular, various types of shear rams commonly used today are hydraulically operated and are typically only designed to cut the tube section of the drill pipe being used, not to stop the flow of fluids. In addition, shear rams rely for proper placement and function on the drill pipe being in a center position of the hole to cut or sever the drill pipe tube only. Most blowouts, however, occur during the tripping phase of drilling, and as a result, other drilling tools such as drill collars and/or downhole tools are frequently within the section to be closed. 
     A further significant cause of failure of blowout preventers used today results from the fact that typically only the body of the BOP is tested at API recommended pressures. The internal components of BOPs used today rely on elastomeric components installed in grooves to make contact with the body of the valve. These elastomeric components will generally not contain higher pressures above 5,000 psi. Therefore, the BOPs in use today are significantly overrated for use in conjunction with higher pressures. 
     SUMMARY OF THE INVENTION 
     The present invention provides an annular blowout container (ABOC) that may be used in conjunction with one or more additional standard blowout containers (BOCs). The ABOC of the present invention incorporates a bladder of approximately 7-10 feet in height that provides approximately 3.5-4.5 feet of tight constrictive seal around whatever pipe or tubing may be in the well bore. The bladder is made of top and bottom rotator plates with springs extending between the plates. The springs are encased in Teflon® and held in place by Kevlar® then covered over completely while in a form with liquid Viton® that is injected to complete the overall bladder in a molded form. 
     These molded bladders may be removed and replaced in the ABOC by removing the top section of the valve housing and twisting out the bladder assembly. Inside the ABOC body are two cavities, one for holding hydraulic oil and the electrically driven hydraulic pump needed for power to activate the rotators, and the second is utilized for holding the batteries in the self contained system. 
     The top and bottom rotator plates are moved in a counter-revolutionary manner as they are affixed to the bladder so as to twist and constrict the bladder to a full grip and sure seal against the pipe or tubing that is in the drill string. The flexible form of the bladder allows it to constrict around irregular components such as collars on the drill string without sacrificing the tightness of seal. The rotators turn the bladder approximately one-quarter of a turn or slightly more to collapse the bladder to the outside diameter of the object in the drill string. This quick rotator action therefore provides the time necessary to get the blowout stopped or stalled out so that heavy mud can be pumped down the hole to stop the pressure at its source. The present ram type BOPs are generally antiquated in that they rely on seals to hold back rated pressures of the fluid flow when in fact the rubber type seals are only rated for up to 5,000 psi and the BOP bodies are open to returning gases, fluids, and solids coming from the drilled hole. These existing BOPs are generally overly complex and rely on the rig as a source for hydraulic oil pressure to activate. 
     The internal bladder in the ABOC of the present invention contains rows of springs that are arranged and placed in between the two steel upper and lower rotator plates. The plates are preferably circular with an internal aperture that is required for the ABOC to be fully open for drilling and/or production purposes. The arrangement of the holes drilled in the plates for installation of the springs are preferably in a circular pattern with the holes being drilled progressing towards the center in a circular pattern toward an inside diameter. A preferred embodiment has four concentric rings of apertures forming attachment points for the springs suspended between the rotating plates. The springs are preferably made in the manner of rebar with external ridges for internal holding power. The springs are preferably constructed from prime steel suitable for spring making. For severe service the springs may be made using suitable alloys that will withstand hydrogen sulfide and carbon dioxide gases, as well as other severe service environments. After the springs are cut to length and heat treated, they are put through a coating process with a first coating of a Teflon® based mixture applied. This first coating is preferably a mixture of Teflon® and other materials that allow the Teflon® to flex and stretch as needed in the compression cycle of the valve. Over the Teflon® mixture coating, a second layer of coating in the form of a Kevlar® mixture is applied. The springs are then installed between the top and bottom plates affixing each end to form the basic bladder. Once the basic bladder has been completed in this manner, it is placed in a mold with the outside diameter and the inside diameters set as needed for the geometry of the valve. Pressurized Viton® is then pumped in and allowed to cure, filling the spaces between the coated springs and inside the mold containment. 
     The upper bladder plate section is attached to the top rotator assembly inside the ABOC. Likewise, the lower section of the bladder plate is attached to the bottom rotator assembly. The function of the rotators is to turn the bottom and top plates in a counter-revolutionary direction a quarter turn or more for each action. When the rotator plates are thus turned, the bladder will compress towards the center contacting and pressing against whatever tube or pipe is in the hole opening. This compression seals off the bottom from the top as a constrictive valve. The molded in Viton® will compress, but is resistant to tear or being shredded. Extreme high flowing gases, liquids and solids can be stalled out (slowed down) for a significant time using the ABOC bladder while other drilling blowout measures are used to load the hole with more drilling fluids that can then be pumped down the drill pipe. The bottom rotator assembly is designed to allow the plate to move up as the twisting action on the bladder is applied. As the height of the bladder is shortened on twisting compression, one portion of the assembly (the top or bottom rotator plate) must be allowed to move towards the center of the assembly. 
     The hydraulic oil contained on the back side of the bladder is compressed further as piston mechanisms move up into the hydraulic fluid. In the same manner, the high pressure gases and fluids enter into a piston assembly under the bottom rotator plate that will additionally compress the hydraulic fluid, thus increasing the pressure on the back side of the bladder sealing element, and further facilitating the force with which the bladder constricts against the tube or pipe. 
     The height of the springs before attaching all of the hardware in the construction of the bladder is preferably about 7-10 feet. Tests show that approximately one-third of the spring section will provide a seal tight grip around the tube or pipe within the center of the bladder assembly. The rotator plates are preferably driven by a number of worm gear drive assemblies through either a direct linkage to the edge of the plate (formed with gear teeth) or through a gear coupling connecting to the hydraulic fluid pumps. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cross-sectional view of the annular blowout container (ABOC) device of the present invention shown with a section of pipe or tubing positioned through the center bore of the assembly. 
         FIG. 2  is a partial cross-sectional view through the middle of the annular blowout container assembly showing one of the two rotator plates in conjunction with the surrounding valve body, as well as one of the two rotating drive mechanisms. 
         FIG. 3  is a detailed cross-sectional view of one edge of the lower rotator plate of the bladder assembly of the present invention showing the manner in which pressurized fluids may flow behind (to the outside of) the bladder wall to facilitate its compression against the interior pipe or tubing. 
         FIG. 4  is a detailed cross-sectional view of a portion of the spring assembly making up a part of the structure of the bladder assembly and the various layers associated with each individual spring and the overall assembly. 
         FIG. 5  is a detailed side plan view of one manner of translating the rotational worm gear drive to one of the rotator plates of the bladder assembly designed to move laterally (upwards) on constriction. 
         FIG. 6A  is an elevational view of the bladder assembly of the present invention shown in an unconstricted configuration. 
         FIG. 6B  is a cross-sectional view of the unconstricted bladder assembly of the present invention shown in  FIG. 6A . 
         FIG. 7A  is an elevational view of the bladder assembly of the present invention shown with rotator plates counter-rotated and with the assembly in an overall constricted configuration. 
         FIG. 7B  is a cross-sectional view of the constricted bladder assembly of the present invention shown in  FIG. 7A . 
         FIG. 8  is a cross-sectional view of a wellhead assembly comprising three of the ABOCs of the present invention in conjunction with a variety of other BOC valves and components. 
         FIG. 9  is a cross-sectional view of a wellhead assembly comprising two of the ABOCs of the present invention linked together with a hydraulic back pressure system useful in conjunction with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is made first to  FIG. 1  for a detailed description of the internal structures of the ABOC device of the present invention. Annular blowout container  10  shown in cross-section in  FIG. 1  is constructed primarily of top section body  12  and bottom section body  14 . Top connector flange  16  connects the ABOC to the upper wellhead assembly (the balance of the components) and bottom connector flange  19  attaches the ABOC to the lower wellhead assembly  20 . Various secure means for connecting top section body  12  to bottom section body  14 , such as the use of a radial array of tapered bolts, may be implemented. 
     A section of drill pipe  22  is shown positioned within the ABOC central bore, although it will be recognized that the tubular component within the bore may be drill pipe or production tubing. Positioned within top section body  12  is top drive assembly  24  which incorporates top drive motor  26 . This drive assembly serves to rotate the top rotator disc  34  as described in more detail below. Associated with bottom section body  14  is bottom drive assembly  28  incorporating bottom drive motor  30 . This assembly serves to counter-rotate bottom rotator disc  36 . 
     The counter-rotation of top rotator disc  34  and bottom rotator disc  36  serves to twist and constrict bladder assembly  38  (shown in a relaxed condition in  FIG. 1 ). When constricted, the bladder assembly has a profile  40  (dashed line) whereby a seal is created against drill pipe  22 . 
     Also within bottom section body  14  are power supply and instrument chamber  32   a  and hydraulic supply chamber  32   b . Power supply and instrument chamber  32   a  contains the necessary electrical batteries to operate the hydraulic pumps that in turn operate top drive motor  26  and bottom drive motor  30 . Also within chamber  32   a  are control electronics and instrumentation connected externally (preferably through a hot stab connection) to the ABOC that allows for both monitoring of the condition of the ABOC and its remote control. In chamber  32   b , both a hydraulic fluid reservoir and the necessary electrically driven hydraulic pumps provide the high pressure hydraulics required to operate the top drive assembly  24  and the bottom drive assembly  28 . Each of the chambers shown may comprise multiple chambers radially arrayed about the center bore of bottom section body  14 . The use of these chambers to hold and house the various operational and control elements of the ABOC eliminates much of the external connections (hydraulic and electrical) that are normally required for such valves. 
     Additional detail highlighted by Detail Section A is described in conjunction with  FIG. 3  and is associated with the operation of a back pressure hydraulic fluid system that facilitates the maintenance of the seal of the bladder against the drill pipe. 
       FIG. 2  shows a partial cross-sectional view looking down on lower valve assembly  50  primarily structured within bottom section body  14 . In this view, drill pipe  22  is shown positioned in the central bore surrounded by bladder assembly  38 . Bladder assembly  38  is positioned integrally with rotator disc  36  (having a gear tooth edge). An array of alignment back springs  42  are positioned around bladder assembly  38  in a manner that allows the assembly to return to an unconstricted configuration after activation. These alignment back springs  42  are positioned on top set plate  44  in a manner described in detail below with reference to  FIG. 3 . 
     Rotator disc  36  is turned (counter to the rotation of the top rotator disc  34 ) by means of bottom drive assembly  28 . Bottom drive motor  30  turns worm gear drive shaft  52  set in position to engage the gear tooth edge of rotator disc  36  and held in place by drive bearing  54 . Power supply and instrument chamber  32   a  and hydraulic supply chamber  32   b  are shown from above in the view of  FIG. 2 . 
       FIG. 3  shows the Detail Section A referenced in  FIG. 1 . Bladder assembly  38  is shown mounted in conjunction with rotator disc  36  that is itself positioned on top set plate  44  and bottom set plate  46 . Alignment back springs  42  are affixed to top set plate  44  and again provide the necessary return force to re-position and re-set the configuration of bladder assembly  38  after use. Intensifier pistons  48  provide a means for conducting high pressure hydraulic fluids to the back side of bladder assembly  38  so as to augment the constrictive force associated with the twisting of the bladder around drill pipe  22 . All of these components are configured within bottom section body  14  and are mirrored in other radial directions about the center bore of the assembly. The upper and lower plates that hold the integrated parts of the bladder together will preferably have O-ring grooves cut to width and depth to hold large diameter and high pressure Viton® O-rings. This would insure a tight seal during installation of the bladder. Such O-ring use, even in very high pressure environments has been proven in the industry. 
       FIG. 4  displays in greater detail the internal construction of bladder assembly  38 . In the expanded detail shown in  FIG. 4 , each individual steel spring  62  is shown to comprise Teflon® layer  64  surrounded by Kevlar® layer  66 . The entire array of springs  62  is then assembled on rotator disc  36  (and rotator disc  34 , shown in  FIG. 1 ) in an array of four concentric circles in the preferred embodiment and positioned within a mold. Liquid Viton® is injected to fill the spaces between the springs to form Viton® layer  68 . This produces flexible bladder wall  60  which, when constricted, seals against the drill pipe or tubing. 
       FIG. 5  shows in greater detail one manner of allowing for the movement of rotator disc  36  laterally (upward) when bladder assembly  38  is constricted. As worm gear drive shaft  52  turns, it causes the rotation of vertical slide gear  72  which in turn rotates rotator disc  36  through its gear tooth edge. Because of the greater width (height) of vertical slide gear  72 , rotator disc  36  may move upward upon the constriction of bladder assembly  38  while still maintaining contact with the gear teeth of slide gear  72 . This eliminates the necessity of adapting worm gear drive shaft  52  to accommodate the lateral movement of rotator disc  36 . 
       FIGS. 6A &amp; 6B  as well as  FIGS. 7A &amp; 7B  show the functionality of the bladder assembly of the present invention.  FIG. 6A  shows an external view of the unconstricted bladder assembly  38  having top rotator disc  34  and bottom rotator disc  36  all of which surround drill pipe  22 .  FIG. 6B  shows these same components internally (in cross-section) and demonstrates the manner in which the annular space around drill pipe  22  permits the flow of fluids (in either direction) through the open bladder assembly and therefore through the ABOC.  FIG. 7A  shows an external view of bladder assembly  38  after the counter-rotation of top rotator disc  34  and bottom rotator disc  36 . It is also noted that bottom rotator disc  36  moves upward during the constriction process. This counter-rotation around drill pipe  22  causes the mid-section of bladder assembly  38  to decrease in both its inside diameter and its outside diameter. The constriction of the inside diameter, of course, provides the necessary seal against drill pipe  22  as shown in  FIG. 7B . The degree to which this seal applies force against drill pipe  22  is in part a function of the degree to which rotator discs  34  &amp;  36  have been counter-rotated. One quarter (90°) turn of each disc will effectively provide a seal that extends over approximately one-third of the overall height of bladder assembly  38 . 
     Repeated use of the same bladder is anticipated both in testing and in actual operations. Despite the capacity to be repeatedly operated, the components of the ABOC that are subject to degradation over time are still primarily confined to the replaceable bladder. In this manner, the ABOC of the present invention may, after an extended period of use, be easily re-built by replacing the bladder assembly and the soft seal components. The hard steel components of the device will need little in the way of replacement or maintenance. 
       FIG. 8  discloses wellhead superstructure  80  made up of an array of valves, BOCs and ABOCs in a configuration associated with well head  86 . The components in superstructure  80  are supported by superstructure support frame  17  shown in dashed outline form for clarity. The assembly shown in  FIG. 8  includes three ABOCs comprising first ABOC  10   a  positioned on top of second ABOC  10   b , which is positioned on top of third ABOC  10   c . This array of ABOCs is positioned on top of blowout container (BOC)  82  as may be one of a number of typical such BOCs in the field. One gate valve  84  may be positioned between the BOC assembly and wellhead  86 . Shear spool  88  forms a primary component of BOC  82 . All of this assembly surrounds drill pipe  22  as shown. A second gate valve  90  is positioned in what is referred to as the “dead man position” at the top of the wellhead superstructure  80 . Other arrangements and numbers of ABOCs and BOCs are anticipated. 
     Reference is finally made to  FIG. 9  which provides one example of a system for facilitating the placement of back pressure against the outside wall of the bladder assembly of the ABOC of the present invention.  FIG. 9  shows a first ABOC  10   a  and a second ABOC  10   b  stacked as referenced in part in  FIG. 8 . Back pressure assembly  100  is generally constructed with flanged outlet  102  into a lower spool of the wellhead superstructure  80  assembly. This conducts the pressure of the drilling or production fluids to hydraulic valve  104  and through right angle fixture  106  to overpressure transfer piston  108 . Right angle fixture  106  is preferably a forged studded connection structured to withstand the rush of high pressure fluids, gases, and solids resulting from the opening the gate valve within the wellhead system. The transfer piston  108  communicates the high pressure of the bore hole fluids to the hydraulic fluid system associated with the ABOCs. Through bladder backside port  110 , the hydraulic fluid system connects by way of T fixture  112  to overpressure transfer piston  108  and additionally upward through high pressure hydraulic line  114  through L-fixture  116  to a corresponding bladder backside port  118  on the first ABOC  10   a . In this manner, the high pressures of the drilling fluids or production fluids that may be experienced within the bore hole during a blowout condition may be transferred to the hydraulic fluids of the ABOCs to provide higher pressure hydraulic fluid that facilitates a back pressure against the bladder assemblies as described above to further strengthen the seal of the bladder against the drill pipe. 
     Although the present invention has been described in conjunction with certain preferred embodiments, it is anticipated that variations in both the size and geometry of the structures may be utilized without departing form the spirit and scope of the invention. To some extent, the geometry of the various components described (the height of the bladder assembly, for example) is determined by the drilling and bore hole environment within which the ABOC is intended to operate. Higher pressure environments may require larger bladder assemblies, whereas lower pressure terrestrial environments may require smaller bladder assemblies. Once again, such variations that are primarily determined by the levels of pressure associated with the operating environment do not necessarily depart from the spirit and scope of the claimed invention.