초록 ▼

The invention is generally directed to a curved flapper and seat for use in a subsurface safety valve. The flapper is biased to a normally closed position to prevent fluid flow through the wellbore. The curved flapper has a sealing surface for engaging a corresponding sealing surface on a seat when

The invention is generally directed to a curved flapper and seat for use in a subsurface safety valve. The flapper is biased to a normally closed position to prevent fluid flow through the wellbore. The curved flapper has a sealing surface for engaging a corresponding sealing surface on a seat when the flapper is in its closed position. The sealing surface of the flapper is configured to contact the sealing surface of the seat along a sinusoidal sealing line, or seam, such that the reactive force from the seat is normal to the sinusoidal seating line. In one aspect, the sealing surface of the flapper has a convex spherical configuration relative to the seat. The sealing surface of the seat, in turn, has a concave conical shape relative to the flapper. When well conditions dictate, a resilient soft seat may optionally be used, and is disposed on the seat proximate the sinusoidal seating line.

대표청구항 ▼

The invention is generally directed to a curved flapper and seat for use in a subsurface safety valve. The flapper is biased to a normally closed position to prevent fluid flow through the wellbore. The curved flapper has a sealing surface for engaging a corresponding sealing surface on a seat when

The invention is generally directed to a curved flapper and seat for use in a subsurface safety valve. The flapper is biased to a normally closed position to prevent fluid flow through the wellbore. The curved flapper has a sealing surface for engaging a corresponding sealing surface on a seat when the flapper is in its closed position. The sealing surface of the flapper is configured to contact the sealing surface of the seat along a sinusoidal sealing line, or seam, such that the reactive force from the seat is normal to the sinusoidal seating line. In one aspect, the sealing surface of the flapper has a convex spherical configuration relative to the seat. The sealing surface of the seat, in turn, has a concave conical shape relative to the flapper. When well conditions dictate, a resilient soft seat may optionally be used, and is disposed on the seat proximate the sinusoidal seating line. late is received between the upper and lower flanges. 13. The wellhead isolation tool of claim 12, wherein the lower support plate has a generally U-shaped cutout adapted to be disposed about the body portion of the lower hub. 14. The wellhead isolation tool of claim 13, wherein the lower support plate has at least one opening therethrough, and wherein the upper and lower flanges of the lower hub have corresponding openings therethrough so that a pin may be inserted through the upper and lower flanges and the lower support plate to connect the lower support plate to the lower hub. 15. A wellhead isolation tool for injecting substances through a passage defined by a wellhead into a well, the wellhead isolation tool comprising: a mandrel defining a mandrel passage, the mandrel having an outer surface and a longitudinal central axis; a valve connected to an upper end of the mandrel, the valve having an open and a closed position, wherein the substances to be injected may be communicated through the valve into the mandrel passage when the valve is in the open position; a threaded drive rod positioned above the valve and operably associated therewith, so that up-and-down movement of the threaded drive rod causes the mandrel to reciprocate in and out of the well through the passage defined by the wellhead, the threaded rod being coaxial with the mandrel; and a drive mechanism for moving the threaded drive rod vertically so that the mandrel is moved in and out of the well. 16. The wellhead isolation tool of claim 15, further comprising a sealing device at a lower end of the mandrel for sealingly engaging an element in the well when the mandrel is received in the well through the wellhead. 17. The wellhead isolation tool of claim 15, wherein the drive mechanism comprises a mechanically driven screwjack. 18. The wellhead isolation tool of claim 15, further comprising a support structure for supporting the mandrel as the mandrel is moved in or out of the well. 19. The wellhead isolation tool of claim 18, wherein the support structure comprises: an upper support plate; a lower support plate; and a plurality of supports legs connected at the upper ends thereof to the upper support plate and at the lower ends thereof to the lower support plate. 20. The wellhead isolation tool of claim 15, further comprising: a wellhead adapter for connecting the wellhead isolation tool to the wellhead, the wellhead adapter having threads at a lower end thereof; and a wellhead adapter sub adapted to connect to the wellhead, the wellhead adapter sub having threads thereon for connecting to the threads on the wellhead adapter. 21. The wellhead isolation tool of claim 20, wherein the wellhead adapter sub comprises: a mounting plate having a plurality of openings adapted to mate with a bolt pattern on the wellhead; and a threaded neck extending upwardly from the mounting plate. 22. A wellhead isolation tool for injecting substances through a wellhead into a well, the wellhead defining a longitudinal passage therethrough, the wellhead isolation tool comprising: a mandrel defining a mandrel flow passage for the substances to be injected, the mandrel having a lower end sealingly engageable with a tubular element in the well; at least one valve connected to an upper end of the mandrel, wherein the substances may be communicated into the mandrel flow passage when the at least one valve is in an open position; a drive rod releasably connected to the at least one valve for reciprocating the mandrel into and out of the well through the longitudinal passage in the wellhead; a lower hub having a passage through which the mandrel passes; a wellhead adapter connected to the lower hub for connection to the wellhead; and a removable support structure for supporting the at least one valve and the mandrel while the mandrel is urged through the wellhead, the support structure comprising: a lower support plate having a vertical support member extending upwardly therefrom, the lower support plate defining a plurality of openings therethrough, the lower hub having a plurality of mating openings, wherein pins may be removably inserted into the openings in the lower hub and the lower support plate, and wherein the support structure may be disconnected and removed by removing the pins and disconnecting the drive rod from the at least one valve after the wellhead adapter is connected to the wellhead. 23. The wellhead isolation tool of claim 22, wherein the wellhead adapter has threads thereon for connecting to threads on a wellhead adapter sub adapted to connect to and extend upwardly from the wellhead. 24. The wellhead isolation tool of claim 23, wherein the wellhead adapter sub has a hole pattern adapted to mate with a bolt pattern on an upper end of the wellhead. 25. The wellhead isolation tool of claim 22, wherein the lower support plate has a generally U-shaped cutout, the cutout being received about a body portion of the lower hub. 26. The wellhead isolation tool of claim 25, wherein the lower hub comprises upper and lower flanges extending radially outwardly from the body portion, and wherein the lower support plate is received between the upper and lower flanges. 27. The wellhead isolation tool of claim 25, wherein the support structure comprises an upper support plate connected to an upper end of the vertical support member, the upper support plate being identical to the lower support plate. 28. The wellhead isolation tool of claim 27, further comprising an upper hub connected to the upper support plate, wherein the drive rod passes through the upper hub. 29. A wellhead isolation tool comprising: a mandrel for reciprocating through a wellhead into a tubular element disposed in a well below the wellhead; a valve connected to the mandrel and movable therewith; a wellhead adapter for connecting the wellhead isolation tool to the wellhead, wherein the mandrel is movable in the wellhead adapter; and a wellhead adapter sub, the wellhead adapter sub having a bolt hole pattern adapted to match a bolt pattern on an upper end of the wellhead, the wellhead adapter sub having a threaded upper end for mating with threads on the wellhead adapter so that the wellhead adapter sub may be bolted to the wellhead, wherein the wellhead isolation tool may be connected to the wellhead by threadedly connecting the wellhead adapter to the wellhead adapter sub. 30. The wellhead isolation tool of claim 29, wherein the threads on the wellhead adapter comprise internal threads, and wherein the threads on the wellhead adapter sub comprise external threads. 31. The wellhead isolation tool of claim 29, wherein the wellhead adapter comprises a wellhead adapter housing and a wing nut connected to a lower end of the wellhead adapter housing, the wing nut having threads defined thereon. 32. The wellhead isolation tool of claim 29, further comprising a support structure for supporting the valve and the mandrel as the mandrel is moved through the wellhead into the well. 33. The wellhead isolation tool of claim 32, wherein the support structure comprises a vertically oriented beam, and wherein the wellhead isolation tool further comprises a roller assembly engageable with the vertically oriented beam for guiding the mandrel and the valve. 34. The wellhead isolation tool of claim 33, wherein the roller assembly is connected to the valve. 35. The wellhead isolation tool of claim 29, further comprising a drive rod for vertically moving the mandrel. 36. The wellhead isolation tool of claim 35, wherein the drive rod is a threaded drive rod, and wherein the wellhead isolation tool further comprises a drive mechanism for moving the drive rod. 37. The wellhead isolation tool of claim 35, wherein the drive rod and the mandrel have a common longitudinal axis. 38. A wellhead isolation tool for injecting substances through a passage defined by a wellhead into a well, the wellhead isolation tool compr