Rotating blowout preventer and method

Abstract

The rotatable blowout preventer 10 comprises a stationary outer housing 12 and a rotatable inner housing 38 having a curved surface 42 thereon defining a portion of a sphere. An annular packer assembly 46 includes spherical packer elements for sliding engagement with the curved surface of the inner housing such that a packer assembly may seal against various sized tubulars. A lower rotary seal 98 between a piston 56 and the outer housing 12 is exposed to the differential between pressurized hydraulic fluid and the well pressure within a lower end of the bore 32 within the outer housing. A flow restriction member 114 between the rotatable inner housing and the outer housing reduces fluid pressure downstream from the flow restriction to less than 40% of the upstream pressure. The upper rotary seal 120 is open to atmospheric pressure and is subjected to this reduced pressure. Improved techniques are provided for passing hydraulic fluid through the blowout preventer for both closing and opening the sealing assembly 46.

What is claimed is:  
     
       1. A rotatable blowout preventer for use in a hydrocarbon recovery operation  sealing pressure in a well including a tubular member passing through the blowout preventer, the rotatable blowout preventer assembly comprising: 
       a stationary outer housing defining a bore therein for receiving the tubular member, the outer housing have a central axis generally concentric with an axis of the tubular member, and the outer housing including a fluid closing  input port and a fluid output port therein;  
       an inner housing rotatable within the outer housing and having an inner curved surface thereon substantially defined by a portion of a sphere having a center substantially adjacent the central axis of the bore ;  
       an annular sealing assembly supported within the inner housing for sealed engagement with the tubular member, a sealing assembly including a plurality of rigid elements circumferentially arranged about the bore of the outer housing, each rigid element having an outer surface for sliding engagement with the inner curved surface of the inner housing, and  the sealing assembly including a resilient member for sealed engagement with the tubular member;  
       a rotatable piston axially movable within the outer housing in response to pressurized fluid in the fluid closing port for causing both axial and radial movement of the annular sealing assembly; 
       a lower rotary seal between the piston and a lower portion of the stationary outer housing  for sealing pressurized fluid within the stationary outer housing from a lower end of the bore in the outer housing;  
       a flow restriction member between the rotatable inner housing and an upper portion of the stationary outer housing  for reducing fluid pressure downstream of the flow restriction member to less than 40% of the pressure upstream from the flow restriction member; and  
       an upper rotary seal between the rotatable inner housing and the upper portion of the stationary outer housing and  downstream from the flow restriction member for sealing the reduced pressure fluid within the outer housing from an upper end of the bore in the outer housing.  
     
     
       2. The rotary blowout preventer as defined in  claim 1 , further comprising: 
       an inner housing bearing for rotatably guiding rotation of the inner housing relative to the outer housing, the inner housing bearing being spaced radially outward from the flow restriction member and within a plane perpendicular to the central axis of the bore and inclusive of the flow restriction member.  
     
     
       3. The rotary blowout preventer as defined in  claim 1 , wherein the flow restriction member is selected from the material consisting of bronze, steel, and ceramic. 
     
     
       4. The rotary blowout preventer as defined in  claim 1 , further comprising: 
       a restriction member bearing for guiding rotation of the flow restriction member relative to the inner housing while maintaining a substantially uniform gap between a radially inward surface of the flow restriction member and a radially outward surface of the rotatable inner housing.  
     
     
       5. The rotary blowout preventer as defined in  claim 1 , further comprising: 
       the flow restriction member is spaced between a radially outward cylindrical surface of the rotatable inner housing and a radially inward cylindrical surface of the outer housing; and  
       a spacing member for radially spacing the flow restriction member relative to the inner housing to maintain a substantially uniform gap between a radially inward surface of the flow restriction member and the radially outward surface of the rotatable inner housing, such that eccentricity between the inner housing and the outer housing varies a radial spacing between a radially outer surface of the flow restriction member and the radially inward surface of the outer housing.  
     
     
       6. The rotary blowout preventer as defined in  claim 1 , wherein: 
       each of the lower rotary seal and the upper rotary seal have a diameter less than 20% greater than a diameter of the bore in the stationary outer housing.  
     
     
       7. The rotary blowout preventer as defined in  claim 1 , further comprising: 
       a fluid flow path between the fluid closing  input port and the fluid output port, the fluid flow path passing by  fluid to the lower rotary seal, radially outward of the piston, radially outward of the rotatable inner housing, past  then through the flow restriction member, past  then to the upper rotary seal, and then through the fluid output port.  
     
     
       8. The rotary blowout preventer as defined in  claim 1 , further comprising: 
       a rotatable piston axially movable within the outer housing in response to pressurized fluid in the fluid closing port for causing both axial and radial movement of the annular sealing assembly; 
       a rotatable adapter ring radially outward of the piston;  
       an upper adapter seal for sealed engagement between the piston and the adapter ring;  
       a lower adapter seal for sealed engagement between the piston and the adapter ring;  
       an opening chamber between the piston and the adapter ring and between the upper and lower adapter seals for receiving pressurized fluid from a fluid opening port in the outer housing to move the annular sealing assembly to an open position; and  
       a bearing member for guiding rotation of the adapter ring with respect to the outer housing, the bearing member and the adapter ring each having a metal surface thereon moved into engagement by pressurized fluid in the fluid opening port for substantially restricting fluid flow from the fluid opening port to the fluid closing port.  
     
     
       9. A rotatable blowout preventer system for use in a hydrocarbon recovery operation including a tubular member passing through the blowout preventer, the rotatable blowout preventer system comprising: 
       a stationary outer housing defining a bore therein for receiving the tubular member, the outer housing having a central axis generally concentric with an axis of the tubular member, and the outer housing including a fluid closing port, a fluid opening port, and a fluid output port therein;  
       an inner housing rotatable within the outer housing;  
       an annular sealing assembly supported within the inner housing for sealed engagement with the tubular member;  
       a pump for generating pressurized hydraulic fluid;  
       a control valve for selectively controlling flow of the pressurized hydraulic fluid to one of the fluid closing port and fluid opening port;  
       a rotatable piston axially movable within the outer housing in response to pressurized fluid in the fluid closing port for causing radially inward movement to the annular sealing assembly;  
       a rotatable adapter ring radially outward of the piston;  
       an upper adapter seal for sealed engagement between the piston and the adapter ring;  
       a lower adapter seal for sealed engagement between the piston and the adapter ring;  
       an opening chamber between the piston and the adapter ring and between the upper and lower seals for receiving pressurized fluid from the fluid opening port to move the piston and the annular sealing assembly to an open position;  
       a lower rotary seal between the piston and a lower portion of the stationary outer housing for sealing pressurized fluid within the stationary outer housing from a lower end of the bore in the outer housing;  
       a flow restriction member between the rotatable inner housing and an upper portion of the stationary outer housing for reducing fluid pressure downstream of the flow restriction member; and  
       a upper rotary seal between the rotatable inner housing and the upper portion of the stationary outer housing and downstream from the flow restriction member for sealing the reduced pressure fluid within the outer housing from a upper end of the bore in the outer housing.  
     
     
       10. The rotary blowout preventer system as defined in  claim 9 , further comprising: 
       an inner housing bearing for rotatably guiding rotation of the inner housing relative to the outer housing, the inner housing bearing being spaced radially outward from the flow restriction member and within a plane perpendicular to the central axis of the bore and inclusive of the flow restriction member.  
     
     
       11. The rotary blowout preventer system as defined in  claim 9 , further comprising: 
       a restriction member bearing for guiding rotation of the flow restriction member relative to the inner housing while maintaining a substantially uniform gap between a radially inward surface of the flow restriction member and a radially outward surface of the rotatable inner housing.  
     
     
       12. The rotary blowout preventer system as defined in  claim 9 , further comprising: 
       the flow restriction member is spaced between a radially outward cylindrical surface of the rotatable inner housing and a radially inward cylindrical surface of the outer housing; and  
       a spacing member for radially spacing the flow restriction member relative to the inner housing to maintain a substantially uniform gap between a radially inward surface of the flow restriction member and the radially outward surface of the rotatable inner housing, such that eccentricity between the inner housing and the outer housing varies a radial spacing between a radially outer surface of the flow restriction member and the radially inward surface of the outer housing.  
     
     
       13. The rotary blowout preventer system as defined in  claim 9 , wherein: 
       a lower seal cartridge ring for supporting the lower rotary seal thereon;  
       an upper seal cartridge ring for supporting the upper rotary seal thereon; and  
       each of the lower rotary seal and the upper rotary seal have a diameter less than 20% greater than a diameter of the bore in the stationary outer housing.  
     
     
       14. A rotary blowout preventer system as defined in  claim 9 , further comprising: 
       a lower seal cartridge ring for supporting the lower rotary seal thereon, the lower cartridge ring having a passageway therethrough;  
       an upper seal cartridge ring for supporting the upper rotary seal thereon, the upper cartridge ring having a passageway therethrough; and  
       a fluid flow path between the fluid closing port and the fluid output port, the fluid flow path passing through the passageway in the lower seal cartridge ring, radially outward of the piston, radially outward of the rotatable inner housing, past the flow restriction member, through the passageway in the upper seal cartridge ring, and then through the fluid output port.  
     
     
       15. The rotary blowout preventer system as defined in  claim 9 , further comprising: 
       the adapter ring being axially movable in response to fluid pressure in the fluid opening port to substantially restrict fluid flow from the fluid opening port to the fluid closing port.  
     
     
       16. A method of controlling actuation of a rotatable blowout preventer for for use in a hydrocarbon recovery operation  sealing pressure in a well including a tubular member passing through the blowout preventer, the rotatable blowout preventer including a stationary outer housing defining a bore therein for receiving the tubular member, an inner housing rotatable within the outer housing, an annular sealing assembly supported within the inner housing for sealed engagement with the tubular member, a piston movable within the outer housing for causing radial movement of the annular sealing assembly,  and a fluid closing  input port and a fluid output port in the outer housing for passing pressurized fluid to the piston through the rotatable blowout preventer, the method comprising: 
       providing a lower rotary seal between the piston and a lower portion of the outer housing  for sealing pressurized fluid within the stationary outer housing from a lower end of the bore in the outer housing;  
       providing a flow restriction between the rotatable inner housing and an upper portion of the stationary outer housing  for reducing fluid pressure downstream of the flow restriction member to less than 40% of the pressure upstream from the flow restriction; and  
       providing an upper rotary seal between the rotatable inner housing and an upper portion of the stationary outer housing and  the downstream from the flow restriction for sealing the reduced pressure fluid within the stationary outer housing from an upper end of the bore in the outer housing.  
     
     
       17. The method as defined in  claim 16 , further comprising: 
       providing an inner housing bearing for rotatably guiding rotation of the inner housing relative to the outer housing; and  
       spacing the inner housing bearing radially outward from the flow restriction and within a plane inclusive of the flow restriction.  
     
     
       18. The method as defined in  claim 16 , further comprising: 
       guiding rotation of the flow restriction relative to the inner housing while maintaining a substantially uniform gap between a radially inward surface of the flow restriction and a radially outward surface of the rotatable inner housing.  
     
     
       19. The method as defined in  claim 16 , further comprising: 
       forming a flow path between the fluid closing  input port and the fluid output port, the flow path passing by  fluid to the lower rotary seal, radially outward of the piston, radially outward of the rotatable inner housing, past  through the flow restriction, past  to the upper rotary seal, and then through the fluid output port.  
     
     
       20. The method as defined in  claim 16 , further comprising: 
       providing a piston removable within the outer housing for causing radial movement of the annular sealing assembly; 
       providing a rotatable adapter ring radially outward of the piston;  
       providing an upper adapter seal for sealed engagement between the piston and the adapter ring;  
       providing a lower adapter seal for sealed engagement between the piston and the adapter ring;  
       forming an opening chamber between the piston and the adapter ring and between the upper and lower adapter seals;  
       passing pressurized fluid through a fluid opening port in the outer housing to move the piston and the annular packer assembly to an open position; and  
       substantially restricting fluid flow from the fluid opening port to the fluid closing port downstream from the opening chamber.  
     
     
       21. The rotatable blowout preventer as defined in  claim 1 ; 
       
         the inner housing having an inner curved surface thereon substantially defined by a portion of a sphere having a center substantially adjacent the central axis of the bore; and  
       
       
         the annular sealing assembly includes that plurality of rigid elements circumferentially arranged about the bore of the outer housing, each rigid element having an outer surface of a sliding engagement with the inner curved surface of the inner housing. 
       
     
     
       22. The rotary blowout preventer as defined in  claim 21 , further comprising: 
       
         a rotatable piston axially moveable within the outer housing in response to pressurized fluid for causing both axially and radially movement of the annular sealing assembly. 
       
     
     
       23. The rotary blowout preventer as defined in  claim 22 , wherein the lower rotary seal acts between the piston and a lower portion of the stationary outer housing. 
     
     
       24. The sealing assembly as defined in  claim 1 , wherein the upper rotary seal is positioned between the rotatable inner housing and an upper portion of the stationary outer housing. 
     
     
       25. The rotary blowout preventer as defined in  claim 1 , wherein the flow restriction member is spaced between a cylindrical surface on the stationary upper housing and another cylindrical surface on the rotatable inner housing. 
     
     
       26. The rotary blowout preventer as defined in  claim 1 , wherein an inner surface of the annular sealing preventer is configured for closing off flow of fluid through the annular sealing assembly when no tubular member passes through the blowout preventer. 
     
     
       27. The method as defined in  claim 16 , wherein the upper rotary seal is spaced between the rotary inner housing and an upper portion of the stationary outer housing. 
     
     
       28. The method as defined in  claim 16 , further comprising: 
       
         positioning the flow restriction between the cylindrical surface on the stationary upper housing and another cylindrical surface on the rotary inner housing. 
       
     
     
       29. The method as defined in  claim 16 , further comprising: 
       
         closing the annular inner sealing assembly to prevent fluid from passing therethrough when the tubular member does not pass through the blowout preventer.