US3318377A

US3318377A - Production wellhead assembly

Info

Publication number: US3318377A
Application number: US363753A
Authority: US
Inventors: Lloyd G Otteman
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1964-04-30
Filing date: 1964-04-30
Publication date: 1967-05-09
Anticipated expiration: 1984-05-09
Also published as: DE1249792B; NL6505405A; GB1065043A

Description

May 9,1967 OTTEMAN 3,318,377

PRODUCTION WELLHEAD ASSEMBLY Filed A ril 19 p 30 64 2 Sheets-Sheet 1 INVENTORI F G L. G. OTTEMAN BY: H714 IS AGENT May 9, 1967 1.. G. OTTEMAN PRODUCTION WELLHEAD ASSEMBLY 2 Sheets-Sheet 2 Filed April :50, 1964 ..'A 'm mm-- QZQWM a a a E Q INVENTORZ v L. G. OTTEMAN 8Y1 HM HIS AGENT United States Patent 3,318,377 PRODUCTION WELLHEAI) ASSEMBLY Lloyd G. Otteman, Metairie, La., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Apr. 30, 1964, Ser. No. 363,753 11 Claims. (Cl. 166-.6)

The present apparatus relates to oil well equipment for use at underwater locations and pertains more particularly to a wellhead closure apparatus for closing the top of a production wellhead assembly in a fluid-tight manner while providing means for re-establishing hydraulic control of components of underwater wellhead assemblies at offshore locations.

The wellhead apparatus of the present invention is related to and adapted to be used on wellhead assemblies of the type found in copending application, Ser. No. 218,- 482, filed Aug. 16, 1962, which is a continuation application of Ser. No. 830,587, filed July 30, 1959, and now abandoned. A recent development in the field of oil well drilling is the completion of wells at offshore locations with the wellhead assembly positioned on or close to the ocean floor out of the way of ships which may damage it in the event of a collision. Equipment on the ocean floor, however, faces problems such as the corrosive nature of the sea water and the presence of marine life which tends to grow and become encrusted on metallic structures below the surface of the water.

Since it is necessary from time to time to go back into a well wherever it has been completed, it is desirable to have an underwater wellhead structure in suitable condition so that pieces of equipment can readily be lowered from the surface of the water and attached to the wellhead structure. It is therefore a primary object of the present invention to provide a wellhead closure apparatus by which an underwater wellhead assembly may be entered for the purpose of carrying out workover operations in the well.

A further object of the present invention is to provide suitable connecting means by which equipment can be lowered from the surface of the water into engagement with an underwater wellhead assembly, which surfaces have been protected against exposure to the sea Water and to marine life.

Another object of the present invention is to provide an apparatus for normally closing the top of a wellhead assembly While providing means for direct vertical access into the well to carry on workover operations therein.

A still further object of this invention is to provide a Well closure apparatus including valves and fluid manifold means whereby tubing strings may be connected to the wellhead assembly to actuate any of the various components of the wellhead assembly.

These and other objects of the present invention will be understood from the following description taken with regard to the drawing, wherein:

FIGURE 1 is a schematic view illustrating several of the components which may be arranged as an underwater wellhead assembly;

FIGURE 2 is a longitudinal view taken partially in cross-section of the top of the wellhead assembly of the present invention;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2; and

FIGURE 4 is a fragmental longitudinal view taken in cross-section of the wellhead assembly of FIGURE 2 illustrating one form of a valve structure.

Referring to FIGURE 1 of the drawing a wellhead assembly or production control unit for an offshore well completed underwater is shown as comprising a casinghead closure apparatus 11 for closing the top of a well casing 12 and securing the wellhead assembly thereto, the

3,318,377 Patented May 9, 1967 "ice wellhead assembly comprising a group of power-actuated components including flow

line control valves

13, 14, 15 and 16, and

swabbing valves

17 and 18 inthe flow lines extending through the assembly, an electro-hydraulic package unit 21 containing a motor, reservoir and pump, and a second package unit 22 containing the various controlling pilot valves which are preferably solenoid-actuated. The entire wellhead assembly may be encased in a container 23. The wellhead assembly may be provided with a pair of

hydraulic pressure lines

24 and 25 which extend through the wall of the container 23 to operate a well component such, for example, as a flow line con nector shown and described in US. Patent No. 3,090,437. The casing closure unit 11 and the wellhead assembly hold-down unit are provided with one or

more tubing strings

19 and 20 as described in greater detail in US. Patent No. 3,064,735. The present invention is concerned with a closure and re-entry apparatus 26 for closing the top of an underwater wellhead assembly and permitting re-entry thereto in order to service or perform other operations on the well.

A Wellhead'closure and re-entry appparatus 26, in accordance with the present invention, is shown in FIG- URE 2 as comprising an elongated cylindrical housing or body member 30 forming the top of the wellhead assembly.

One or more vertical conduits, such, for example, as

conduits

31 and 32 of FIGURE 3, extend through the entire length of the closure means and re-entry body member 30 and are in fluid communication with the tubing strings 19 and 20 (FIGURE 1) which depend within the well casing 12. A second pair of

vertical conduits

33 and 34 extended downwardly into or through the body member 30 to provide fluid communication with various hydraulic components of the wellhead assembly. These

conduits

33 and 34 are each preferably provided with one or more seating shoulders or annular recesses such as those illustrated at 35-39 whereby various tools, valves and/ or other devices may be definitely positioned at various points therein.

Extending through the side wall of the body member 30 near the bottom of

conduits

33 and 34 are side conduits 40 and 41 arranged in fluid communication with each other, as by a flushing fluid by-pass line 42 which may bend around the outside of the body member 30 as illustrated in FIGURE 3 or may form an integral part of said body member.

Each of the

vertical conduits

33 and 34 and the body member 30 are also in communication through the wall thereof with one or

more conduits

43, 44 and 45 (FIG- URE 2) which lead to and are in communication with various hydraulically-operated components of the wellhead assembly. Thus, for example, the vertical bore 33 is in communication through conduit 46 and thence through a fluid port 47 in the stem 48 of valve 49, and into conduit 51 to which conduit 44 is connected. As shown in FIGURE 4, the actuator head 53 of an actuator tool positioned in bore 33 engages the end 54 of the valve stem 48 which normally protrudes into the vertical conduit 33 and forces the stem 48 back against the compression spring 55 so as to open the valve 49 and bring the fluid conduit 51 into communication with the conduit 46. The actuator head 53 is provided with upper and lower

tapered surfaces

56 and 57, respectively, so that the actuator head 53 can open or pass a valve without hanging up on it.

As shown in FIGURE 2, the re-entry body member 30 is also provided with any number of other valves 58 through 62 which are similar to valve 49. Since the flow conduits 62 and 63 come away from the

valves

58 and 59, respectively, at an angle to the flow conduit 51, as

3, shown in FIGURE 3; for ease of illustration they are not included in FIGURE 2. However, the

conduits

51, 62, and 63 are in communication at one end with the

flow conduits

44, 45 and 43, respectively, and on the other end with the conduit 46 which is in communication with the vertical conduit 33. Preferably, the inlet end of the conduit 46 may be provided with any suitable type of a screen, such for example, as ,a cylindrical screen 65a which is seated on a shoulder 37a formed on the wall of the vertical conduit 33, while the upper end of the screen 65 may be locked in place, as by screw threads 66. Ina like manner verticalconduit 34 is provided with a cylindrical screen 65; However, in some instances, when vertical conduit 34 is being used as a return line for fluids passing upwardly through conduit 34, it may be preferable to omit the screen 65 from the conduit 34 thereby preventing any particles in the system from clogging the outside of the screen and preventing the return of fluid through the screen. Normally, however, two screens 65 and 65:1 are employed especially during the flushing period when fluid is flushed down conduit 33 around the flushing fluid bypass line 42 and up the vertical conduit 34.

The top of the body member 30 may be recessed, as at 70. The recess 70 is provided to receive a suitable plug (not shown) having at least a portion of the outer surface made of rubber whereby a fluidtight seal is formed between the plug and the inner wall of the body member I 30 within the recess 70 so that the top of one or more .vertical conduits, for example, 33 and 34, passing down through the body member, are closed in a fluidtight manner. Preferably, the wall of the recess 70 is provided with an annular groove 71 for receiving spring-loaded latching vdogs or fingers adapted to seat within the recess.

The construction of a preferred plug 69 for sealing the upper end of a body member of the present invention 'is described in detail in US. Patent 3,050,127. It is to be understood that rather. than forming the recess 70 in the top of the'body member 32 to receive a plug, a cap-type is provided withan annular recess 74 cut in the outer surface vthereof,io r any other suitable anchoring device formed onthe outer surface thereof, at least the upper portion of thebody member 30 is preferably encased-in a temporarily removable or retractable sleeve which may act as an outer casing to minimize corrosion and the growth ofmarine organisms on the outer surface of the body member 30 whichmight prevent the orientation of the running tool head or other equipment. Such a protective outer casing on the body member 30 may take the form, as illustrated in FIGURE 2, of a spring-loaded bellows sleeve in the form of a thin flexible wall 75 which may befixedly secured at the top and bottom to ring

members

76 and 77, respectively, the upper, ring member 76 being slidably mounted in a low-pressure fluidtight engagement with the outer surface of the body member .30. 'A compression spring arranged within the flexible s1eeve'75 and between

ring members

76 and 77 maintains the-sleeve 75 in its normally extended position, as illustrated. The

ring members

76 and 77 may be covered with rubber or any other suitable sealing means to form a substantially low-pressure fluidtight seal around the body member and against a plug 69 (FIGURE '1) when it is positioned in recess 70.2 A seal of thistypeis illustrated in FIGURE 2 as element 79. The spring-loaded protective bellows or sleeve 75' extends from the top of the body member 30 downwardly adistance sulficient so that in its operative position the sleeve covers at least'allof the outer surface of the body member from the top thereof to a point below the annular groove 74 to be engaged by a running tool, and also extends a suflicient distance below this point so that the spring-loaded sleeve may be compressed Without being injured. A springloaded chemically inert bellows is preferred. The wall 75 of the sleeve can be made of flexible metal or any flexible rubber-like or plastic material. A port in the ring member 77 is provided with a grease fitting 81 by which a grease may 'be injected into the annular space between the outer surface of the .body member 30 and the inner surface of the sleeve 75. This displaces any sea water which has entered.

While the upper ends of the

vertical conduits

33 and 34 are illustrated as being of the same diameter, it is to be understood that they may be of different diameters to facilitate the running of tubing string into the

various conduits

33 and 34 and maintain identity as to which one is connected to which tubing, to be inserted later. Thus, if vertical conduit 33 had a diameter an eighth of an inch larger than conduit 34, the larger of two tubing strings would be run into the wellhead assembly first to make sure that it was seated in conduit 33. Only a single tubing string 82 is illustrated as having its lower end positioned within the upper end of conduit 33, it being understood that a second tubing string could be similarly inserted in the upper end of conduit 34.

Any suitable type of latching means may be employed to secure the lower end of a tubing string 82 in the upper end'of its mating conduit 33. For example, simple screw threads may be employed or a combination of a pin and J-slot mechanism, both being well knownto the art. Alternatively, the recessed upper end of the

vertical conduits

33 and 34 may be provided with a series of screwthread shoulders in which the lower end of a tubing string may be stabbed. In this case, the lower end of the tubing string 82 is provided with a helically-wound spring 83 which. is adapted to stab into seating position by vertical movement of the tubing string and may be later disconnected therefrom by rotation of the tubing string to the right. Connections of this type are common to the art and are manufactured by Baker Oil Tool Company.

In order to enter a wellhead assembly closed by the apparatus in accordance with the present invention, a string of pipe known as a marine conductor pipe (not shown) and having a running head secured'to the lower end thereof would be lowered from a drilling barge down through the water to the ocean floor in a manner described in copending application Ser. No. 218,482 filed Aug. 16, 1962. As the running and latching head of the marine conductor pipe is lowered down on the top of the body member 30, which at this time would still be closed at the top by means of a plug 69 (FIGURE 1), the lower end of the running head or pipe string would come in contact with the upper ring 76 of the protective sleeve unit 75-78, forcing it downwardly along the side of the body member 30. By. providing a skirt 84 extending.

downwardly'from the slidable ring 76, damage to the sleeve unit by extreme compression is prevented. A fishing tool would then be run down to remove the plug from the recess 70 and, after running tubular strings (not shown) into

conduits

31 and 32, separate tubing strings,

as 82, would be run into the

vertical conduits

33 and 34 and locked therein. Fluid would then be pumped down tubing string 82 from the vessel at the surface, and forced through vertical conduit 33, around flushing by-pass line 42, up through the vertical conduit 34 and thence upwardly through a mating tubing string (not shown), if desired, to the surface.

With

vertical conduits

33 and 34 having been thoroughly flushed out, which action also cleans the inner surfaces of the

cylindrical screens

65 and 65a, a plug 85 'is dropped or run down one of the conduits, say conduit 33 so as to close the flushing fluid bypass line 42. The

plug 85 is preferably run at the lower end of a valve-actuating tool which may comprise a valve actuator head 53 with a shaft 86 connecting it to the plug 85 at its lower end and with a hollow perforate stem 87 connecting it to a suitable hollow or tubular latching body 88 adapted to seat in the lower end of the tubing string 82 and being secured therein, if desired, against upper movement by suitable latches 89. The latches 89 are only necessary in the event that fluid is to be circulated upwardly through one of the

valves

49, 58, or 59 and thence up through the tubular latching body of the valve actuator mechanism. The combination valve actuator mechanism together with the plug 85 may be lowered and retrieved by wire line in a manner well known to the art. Preferably, it would be run in on a wire line and pulled back until the latches 89 latched in their mating grooves so that the operator would be certain that the valve actuator head 53 was positioned opposite the valve to be opened. Alternatively, other spacing arrangements may be made to assure the operator that the proper valve is open. Thus, the stem 87 may be selected of a length such that when the valve actuating mechanism is seated in the lower end of the tubing string 82, the proper valve would be open. Alternatively, the position of the valve actuator head could be adjusted by changing the length of the shaft 86 between the plug 85 and the valve actuator head 53.

In the event that wellhead assembly employed hydraulically-operated components such as valves, lock down devices, etc., which were actuated in both directions hydraulically, that is, to an open or closed position or to a locked or unlocked position by applying hydraulic pressure in one direction or the other, it may be seen that the apparatus of the present invention could be employed to operate three hydraulically-operated wellhead components since the body member is provided with six

valves

49, 58, 59, 60, 61, and 62 in the control conduits.

Thus, in order to pump hydraulic pressure fluid through valve 58 to operate a wellhead component, the corresponding valve 60 on the other side of the body member must be opened to allow hydraulic fluid from in back of the piston of the hydraulically-operated component to move up conduit 34. In this case, therefore, it would be necessary to insert a valve-actuating mechanism as described with regard to the one in conduit 33, to be placed or dropped in the lower end of a second tubing string (not shown) which would be latched in the upper end of vertical conduit 34. The actuated tool in conduit 34 would not need to have a plug 85 attached to the lower end thereof as a single plug is all that is necessary to plug the flushing fluid by-pass line 42.

If on the other hand the hydraulically-operated components of the wellhead assembly are spring-loaded in one direction, it is quite apparent that only the single tubing 82 would be needed in order to operate a single valve, say valve 58, in order to provide hydraulic pressure fluid to the wellhead conduit to actuate it. Thus, in the arrangement illustrated in FIGURE 2, the six valves could be employed to control auxilliary hydraulic pressure fluid lines to siX components.

I claim as my invention:

1. In a well installation having pressure-fluid actuated components located underwater at an offshore location, a re-entry head on said well installation comprising:

a body member having a pair of longitudinally fluid passageway bores closed at their lower ends and extending downwardly from the upper end of said body member,

flushing conduit means interconnecting the lower end of said pair of longitudinal bores whereby fluid may be flushed down one bore and up the other bore,

side conduit means through the wall of said body member in communication between at least one of said longitudinal bores and at least one of said pressureactuated components of said well installation,

said body member having means above said side conduit means for receiving and sealing a removable flow conductor, and

valve means in said side conduit means for controlling fluid flow therethrough,

said bore having said side conduit means being provided below said side conduit means with an internal annular seal surface engageable by sealing means of a well tool.

2. The apparatus of claim 1 including filter means carried in said bore across the opening of said side conduit means.

3. The apparatus of claim 1 wherein each of said longitudinal bores is provided with side conduit means and including valve means in all of said side conduit means.

4. The apparatus of claim 1 wherein said valve means of said side conduit means include valve stem means normally extending into the bore of said body member and engageable by a valve operating well tool when said well tool is positioned in said bore.

5. The apparatus of claim 4 well tool means positioned in the bore of said body member at a point opposite to and engagement with said valve stem means of said valve means.

6. The apparatus of claim 5 wherein said well tool means is provided with seal means at the lower end thereof for engaging said seal surface of said bore to close said flushing conduit means.

7. The apparatus of claim 1 wherein both of said bores are provided with side conduit means and valve means for closing said side conduit means.

8. The apparatus of claim 7 wherein both of said longitudinal bores are provided with means for receiving and sealing flow conductors.

9. The apparatus of claim 8 including flow conductors having their lower ends sealed in the bores of said body member and being of a length to extend to a point above the surface of a body of water in which the well installation is positioned.

10. The apparatus of claim 9 including sealing means carried on the outer surfaces of said flow conductors near the lower ends thereof for engaging the inner surfaces of said bores of said body members above the side conduit means thereof, and internal groove latch means on the inner wall of said flow conductors near the lower ends thereof, said groove latch means being engageable by locking means of well devices for releasably securing well devices in said conductors.

11. The apparatus of claim 10 including valve actuating well devices having latching means for engaging said internal groove latch means and having valve stem actuating means carried at a predetermined distance below said latching means to engage said valve stem means of said valve means.

References Cited by the Examiner UNITED STATES PATENTS 3,054,456 9/1962 Hammaker 16646 X 3,064,735 11/1962 Bauer et a1. 166.6 3,086,590 4/1963 Jackson et al. 166.6 3,142,337 7/1964 Poorman et al. 166.6 3,163,224 12/1964 Haeber et al. 166.6 3,186,486 6/1965 Rhodes et al. -7 X 3,189,098 6/1965 Haeber 166.6 3,219,117 11/1965 Johnstone et al 166-.5

CHARLES E. OCONNELL, Primary Examiner.

ERNEST R. PURSER, Examiner.

R. E. FAVREAU, Assistant Examiner.

Claims

1. IN A WELL INSTALLATION HAVING PRESSURE-FLUID ACTUATED COMPONENTS LOCATED UNDERWATER AT AN OFFSHORE LOCATION, A RE-ENTRY HEAD ON SAID WELL INSTALLATION COMPRISING: A BODY MEMBER HAVING A PAIR OF LONGITUDINALLY FLUID PASSAGEWAY BORES CLOSED AT THEIR LOWER ENDS AND EXTENDING DOWNWARDLY FROM THE UPPER END OF SAID BODY MEMBER, FLUSHING CONDUIT MEANS INTERCONNECTING THE LOWER END OF SAID PAIR OF LONGITUDINAL BORES WHEREBY FLUID MAY BE FLUSHED DOWN ONE BORE AND UP THE OTHER BORE, SIDE CONDUIT MEANS THROUGH THE WALL OF SAID BODY MEMBER IN COMMUNICATION BETWEEN AT LEAST ONE OF SAID LONGITUDINAL BORES AND AT LEAST ONE OF SAID PRESSUREACTUATED COMPONENTS OF SAID WELL INSTALLATION, SAID BODY MEMBER HAVING MEANS ABOVE SAID SIDE CONDUIT MEANS FOR RECEIVING AND SEALING A REMOVABLE FLOW CONDUCTOR, AND VALVE MEANS IN SAID SIDE CONDUIT MEANS FOR CONTROLLING FLUID FLOW THERETHROUGH,