BACKGROUND OF THE INVENTION
In the oil industry, lubricator devices are used for servicing wellheads. In general, such devices are elongated and tubular in structure. The device is affixed to a wellhead and a tool or other workover piece is lowered from it by means of a winch and wire line down into the well.
The well, of course, contains fluid such as gas or oil under pressure. If the lubricator is not provided with sealing means, a certain portion of the oil or gas will be forced out the lubricator to contaminate surrounding equipment and perhaps workmen in the area.
Heretofore, it has been the practice to place a seal or hydraulically actuated packing element in the upper end of the lubricator. Generally, this device has been constructed of rubber or other compressible material. To prevent seepage of gas or oil through the packer, it is essential that the seal or packer squeeze inwardly against the wire line as tightly as possible. However, it will be obvious that if the packer is squeezed too tightly against the wire, it soon will be worn away by the wire rubbing against it. On the other hand, when the packing is too loose, there may be relatively large leakage of oil or gas through the device.
Such leaking is a problem as regards both land and underwater wells because of the resulting contamination of the surrounding area. Such contamination is particularly undesirable in the case of underwater oil and gas wells when the servicing is done from inside a watertight underwater chamber provided for workmen. As will be appreciated, the amount of gas buildup may become dangerous within the closed chamber; or if it be an oil well, the mess from leaking oil soon can become intolerable to the workmen within the chamber.
SUMMARY OF THE INVENTION
The present invention provides a lubricator assembly device adapted for mounting on a wellhead. The lubricator device comprises an elongated tubular member having a central bore. The member is closed at one end by an inwardly compressible packer means and is provided with securing means for removably attaching the other end to the wellhead.
Additionally, adjustable sealing means is mounted within the bore of the member near the end provided with said securing means. The packer and sealing means define a zone in the bore of the member through which a fluid is circulated. A wire line passes through the packer, fluid circulating zone, and sealing means to lower a tool or other workover device downwardly into the well. By passing fluid such as water, sea water or the like through the circulating fluid zone, it will be seen that a fluid seal is provided within the packer which will prevent oil, gas or other fluid in the well from escaping from the lubricator and contaminating the atmosphere as well as men and material located within the surrounding area.
It is a feature of the invention that the lubricator can be transported by a chamber adapted to be submersed into mating relationship with an underwater well to provide an environmentally safe watertight compartment for workmen servicing the well.
DESCRIPTION OF THE DRAWINGS
For more complete understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is an elevational view in cross section with parts broken away illustrating the lubricator assembly device of the present invention mounted upon a wellhead, the whole being enclosed within a watertight, underwater chamber, and
FIG. 2 is an elevational view in cross section with parts broken away illustrating a second embodiment of the lubricator assembly device of this invention,
FIG. 3 is an elevational view in cross section with parts broken away illustrating one form of a quick connect-disconnect coupling.
DESCRIPTION OF PREFERRED EMBODIMENTS
The lubricator assembly device of this invention is adapted for mounting on land wells and on wells which are located underwater. For convenience, the device will be described in conjunction with a submersible chamber as it can be used for servicing underwater wells. It functions in exactly the same manner when used on land wells except, of course, that the chamber then is not required.
Looking first at FIG. 1, the lubricator assembly device of this invention is referred to generally by reference number 10. The lubricator is shown being carried within a watertight, underwater chamber 12 adapted to be transported by a surface vessel (not shown) to a location above a submerged well provided with a wellhead 14.
Lubricator assembly device 10 includes an elongated tubular member 16 closed at one end by an inwardly compressible packer means 18. The other end of tubular member 16 is provided with securing means, indicated generally by reference number 20, for removably attaching the member to wellhead 14. That means conveniently comprises a quick connect-disconnect coupling. As illustrated in FIG. 3, the coupling is provided by forming the upper end of wellhead 14 with an outwardly extending shoulder and the end of tubular member 16 with a flared-out portion adapted to fit over the shoulder and to be fixed in place by bolts 21. It will be understood, of course, that the quick connect-disconnect coupling shown in FIG. 3 is set forth for illustration purposes only and that any commercially available equivalent coupling is suitable for use in accordance with this invention. Alternatively, as shown in FIG. 1 and 2, the securing means may include a pair of abutting flanges 22 and 24 located respectively on member 16 and wellhead 14. Flanges 22 and 24 are secured together by suitable means such as bolts 26.
Adjustable sealing means 28 is located within member 16 near securing means 20. The adjustable sealing means conveniently comprises a standard blowout preventer type valve. A wire line 30 passes through tubular member 16 and is adapted to be wound around winch 32 and to carry, on its other end, a tool 34 or other workover device. Inwardly compressible packer means 18 is adapted to tightly surround wire line 30 to minimize outward seepage of fluid into chamber 12.
Tubular member 16 is provided with a hollow central bore 36. It will be seen that the bore comprises a hollow zone 37 bounded at one end by packer 18 and at the other end by sealing means 28. The zone 37 is adapted to receive a circulating fluid such as water, sea water or the like. In this connection, inlet means 38 is provided in the wall at one end of tubular member 16 and outlet means 40 is provided at the other end of the tubular member. Fluid such as sea water is introduced into zone 37 in bore 36 through inlet 38 and outwardly to the sea through outlet 40.
In using the lubricator assembly device of the present invention, it is placed in chamber 12 and transported to the region of the well by means of a surface vessel, not shown. Once the vessel is above the well, the chamber is lowered by a cable or other suitable means to the well. The wellhead protrudes a few feet above the mudline and is provided with a platform or other suitable supporting means, not shown, to which the chamber is joined to provide a watertight seal. Before the lubricator assembly is connected to the wellhead, workmen inside chamber 12 attach a work tool 34 to the end of wire line 30, open seal 28, and then pull the tool upwardly into the tubular member 16 by operating winch 32. Seal 28 and outlet 40 may be positioned as shown on the drawing or they can be located in a region closer to the other end of member 16. In the latter instance, it will be appreciated that there would be sufficient room to pull tool 34 into member 16 without opening seal 28, and seal 28 could be replaced by a packer 18.
Member 16 then is secured to the top of the wellhead by securing means 20. Adjustable sealing means 28 then is opened to provide a passageway wide enough to permit work tool 34 to pass therethrough and down into the upper part of the wellhead. After the work tool 34 has passed adjustable sealing means 28, that sealing means is clamped inwardly against wire line 30 to prevent seepage of fluid upwardly into bore 36. Suitable valves, not shown, mounted on conduits 38 and 40 are opened to permit the circulation of sea water through zone 37 in bore 36 of tubular member 16. Once the passage of sea water through zone 37 has been established, winch 32 is actuated to lower the wire line 30 and work tool 34 down into the well.
After the well has been serviced, winch 32 is actuated to withdraw wire line 30 and work tool 34 from the well and upwardly back into tubular member 16. The flow of circulating fluid through zone 37 is stopped and adjustable sealing means 28 is opened to permit the free passage of work tool 34 back up into member 16.
Packer 18 and sealing means 28 clamp relatively tightly about wire line 30, there being only enough clearance to permit the wire line to move without causing undue wear on the packer and seal.
The fluid circulating through zone 37 of bore 36 prevents fluids such as oil or gas from the well from escaping into chamber 12 or, in the case of a land well, to the surrounding area.
In the modification illustrated in FIG. 2 of the drawing, there is shown a lubricator assembly device including a plurality of additional zones for the circulation of fluid such as sea water. In this embodiment, for illustration purposes, three zones 42, 43 and 44 are shown positioned below zone 37. These zones are bounded by adjustable sealing means 28. As wire line 30 and tool 34 are lowered into the well, it is possible that some of the fluid circulating in zone 37 may seep along the wire line into zone 42. Any fluid which passes into zone 42 will be withdrawn through conduit 46 by the suction action of fluid passing through inlet 38'. As shown on the drawing, fluid passes from zone 43 to zone 44 through conduit 48. As shown on the drawing, the fluid, preferably sea water, circulating through zones 43 and 44 is introduced into those zones through inlet 38' and is returned through outlet 40'.
It will be appreciated that it is possible to connect outlet 40 (FIG. 1) to inlet 38' (FIG. 2) whereby to provide an integral fluid circuiting system through the device. Moreover, the device can be constructed whereby zones 42-44 are located above or in place of zone 37. When these zones are above zone 37, the seals all can be of the inwardly compressible type 18. When the zones are in place of zone 37, at least the upper seal is of the inwardly compressible type. In these latter two modifications, zone 42 may be omitted, if desired.
The fluid circulating through zone 37 (FIG. 1) may be at any desired pressure. Thus, it may be at a pressure greater than, equal to, or less than the pressure of the fluid in the well. It is preferable, however, to pass the circulating fluid through the zone at a pressure greater than that of the fluid in the well. When lower pressures are used, oil or gas contaminants from the well may pass upwardly through seal 28. This does not result in any severe contamination problem, however, because that fluid will be carried out of zone 37 through outlet conduit 40. Further, should any fluid seep from zone 37 out through seal 18, there is no resulting contamination of the surrounding area by anything other than that clean circulating fluid. When the device is constructed to include a plurality of zones (FIG. 2) the same or different pressures may be employed in such zones.
While the invention has been described with respect to what are considered to be the preferred embodiments thereof, it will be understood, of course, that certain changes, substitutions, modifications and the like may be made therein without departing from its true scope as defined in the appended claims.