US3064735A

US3064735A - Wellhead assembly lock-down apparatus

Info

Publication number: US3064735A
Application number: US834096A
Authority: US
Inventors: Richard J Bauer; John A Haeber; Lloyd G Otteman; Raymond F Perner
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1959-08-17
Filing date: 1959-08-17
Publication date: 1962-11-20
Anticipated expiration: 1979-11-20
Also published as: GB924904A

Description

Nov. 20, 1962 RJ. BAUER ETAL 3,064,735

WELLHEAD ASSEMBLY LOCK-DOWN APPARATUS Filed Au 17, 1959 s Sheets-Sheet 1 CABLE 5 INVENTORSI 22 R. J. BAUER J. A. HAEBER 37 23 38 24 1.. e. OTTEMAN Fla R. F. PERNER BYIAHHJ41 THEIR AGENT Nov. 20, 1962 R. J. BAUER ETAL WELLHEAD ASSEMBLY LOCK-DOWN APPARATUS 3 Sheets-Sheet 2 Filed Aug. 17. 1959 N HM E JR-EN T U TR N ATE E QW HOP G R M 0 w f ERIMLR .E V H N AW B 1962 R. J. BAUER ETAL 3,064,735

WELLHEAD ASSEMBLY LOCK-DOWN APPARATUS Filed Aug. 17. 1959 s Sheets-Sheet a INVENTORSI R. J. BAUER J. A. HAEB L.G. OTTE N R.F. PERNER THEIR AGENT tent hoe 3,54,735 Patented Nov. 20., 1962 3,064,735 WELLHEAD ASSEMBLY LQCK-DOWN APPARATUS Richard ll. Bauer, Littleton, C010,, and John A. Haeber, Lloyd G. Gtteman, and Raymond F. Perner, Houston, Tex, assignors to Shell Gil Company, a corporation of Delaware A Filed Aug. 17, 1959, Ser. No. 834,996 All Ulaims. (Cl. 166-665) This invention relates to apparatus for use on offshore wells and pertains more particularly to wellhead apparatus adapted to be securely locked on a well casinghead positioned underwater. The present invention is especially concerned with apparatus for closing an underwater well casinghead in a fiuidtight manner and providing flow control equipment therefor, all of which may be operated from a remote control station.

In an attempt to locate new oil fields an increasing amount of well drilling has been conducted at offshore locations, such for example, as off the coast of Louisiana, Texas, and California. As a general rule, the strings of casing in a well together with the tubing string or strings extend to a point well above the surface of the water Where they are closed in the conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the top of said casing. Attempts have recently been made to provide methods and apparatus for drilling and completing a well wherein both the well casinghead and subsequently the wellhead assembly and casinghead closure device are located underwater at a depth sufficient to allow ships to pass over them. Preferably, the casinghead and wellhead closure assemblies are located close to the ocean floor. in order to install equipment of this type underwater in depths greater than the shallow depths at which a diver can easily operate, it has been necessary to design entirely new equipment for this purpose. Thus, after drilling and completing an oil or gas well at an offshore location in a manner described in copending patent application, Serial No. 830,538, filed July 30, 1959, and entitled, Underwater Well Completion Method, the well casinghead may be closed by the equipment of the present invention.

it is therefore an object of the present invention to provide a wellhead assembly and casing closure apparatus adapted to be lowered on guide lines and seated on an underwater well casinghead and securely locked thereon by operations carried out at a remote location without the rotation of one element relative to another.

It is also an object of the present invention to provide apparatus for lock'ng apparatus such as blow-out preventers, wellhead assemblies, etc, to an underwater well casinghead with the operation being carried out from a remote location.

A further object of the present invention is to provide a remotely-operable casing closure apparatus adapted to pack off the annulus between the tubing string or strings and well casing in an underwater well casinghead.

Another object of the present invention is to provide a remotely-controlled liydraulically'operated' tubing hanger and lockdown and sealing apparatus for holding and sealing strings of tubing in a well against well pressures therein at all times, even in the event that the hydraulic pressure lines to said apparatus should break, or otherwise become inoperative.

A still further object of the present invention is to provide a wellhead assembly and easing closure apparatus which may readily be unlocked from an underwater well casinghead and withdrawn together with the string or strings of well tubing to an operational base at the surface, for example, to a drilling barge or platform.

Another object of the present invention is to provide a casing closure apparatus adapted to seat within an underwater well casinghead, rather than on the outside thereof, so that a well casinghead of small diameter may be employed thereby permitting equipment of minimum size to be used in the drilling and completion of the well.

These and other objects of this invention will be under stood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view, taken in longitudinal cross-section, of a wellhead assembly of the present invention seated on the top of a well casinghead;

FEGURE 2 is a diagrammatic view taken in longitudinal cross-section of a continuation downwardly of FIGURE 1 to illustrate the casing closure and lockdown apparatus for holding the wellhead assembly and easing closure apparatus Within an underwater well casinghead;

FEGURE 3 is a diagrammatic isometric view of a wellhead positioned on the ocean floor; and,

FIGURE 4 is a partial cross-section View of another form of the actuating means of the hold-down mechanism of the present invention.

Referring to FIGURE 2 of the drawing, a typical underwater well installation incorporating the apparatus of the present invention comprises an underwater casingbead ll having a casing and tubing suspension body 12 positioned therein on a seat 13. A series of strings of casing l t, 15, and is are suspended Within the casing and tubing suspension body 12 from suitable hangers 17 and ES. If desired, the outermost casing 16 may be welded, as at l9, to the lower end or" the casing and tubing suspension body 12. While the casinghead 11 is illustrated with a casing and tubing suspension body 12 suspended therein, in some installations the casing and tubing suspension body may form an integral part of the casinghead ll.

Positioned within the bore of the casing and tubing suspension body 12. in the upper end thereof is a casinghead closure body 22 having one or more

vertical bores

23 and 24 therein.

Tubin strings

25 and 26 are fixedly secured to the bottom of the casinghead closure body 22 in register with the

bores

23 and 24 therein. The connection between the

tubing strings

25 and 26 and the bottom of the closure body 22 may be made in any suitable manner as by threading, as illustrated at 27 in FIGURE 2. An element such as a plug 39, having one or more O-ring seals 31 therein, surrounds the

tubings

25 and 26 and forms a fluidtight seal between the

tubing strings

25 and 26 and the Wall of the adjacent casing hanger l7 and casing string 14. A seal 32 (FIGURE 1) is provided in the sloping face 33 of the top of the closure body 22 to keep sea-Water out of the installation. Additionally, another annular seal 34 may be employed if desired.

The seal 34 is expandable against the inner surface of the casing and tubing suspension body 12, as shown in the right-hand side of FIGURE 2, by means of a tubularshaped piston element 35. The piston 35 is slidably mounted within an annular chamber 36 (FIGURE 2). A pair of

conduits

37 and 38 extending through the closure body 22 are in communication with the upper and lower ends of chamber 36.

The closure body 22 is also provided with a series of outwardly extendable locking dogs 49 which are adapted to be forced outwardly into an annular groove 42, cut in the inner face of the suspension body 12, upon downward movement of piston 35. The piston member 35 is provided with a downwardly and inwardly sloping face 43 which forces the dogs into their locking position, as shown on the right-hand side of FIGURE 2. The outer upper edges of the locking dogs 41 are preferably bevelled, as at 44-, whereby with the piston in its upper position,

aoeavss 3 as shown on the left-hand side of FIGURE 2, the dogs 49 are retracted into the closure body 22 upon an upward pull of the closure body 22 with respect to the casing and tubing suspension body 12.

Referring to FIGURE 1 of the drawing, the vertical bores or

conduits

23 and 24 in the casing closure body 22 are illustrated as being closed by a valve 45 which is preferably a dual flow passage valve having full opening gates and/or plugs therein, a type well known to the art, so that the passages through the valve 45 are of at least the same diameter as the

bores

23 and 24. Vertically extending above the valve 45 and fixedly secured thereto in a fluidtight manner is a spool piece 46 having dual bores47 and therein which are in register through the flow passages in the valve 45 with the

vertical bores

23 and 24 of the closure body 22. While the valve 45 is described as having dual flow passages therethrough, it is realized that two single valvescould be used instead.

The spool piece 45 is provided with a pair of

side conduits

51 and 52 which may come off the spool piece at right angles to the spool piece, but preferably branch off of the spool piece in a gentle sloping curve, as illustrated, thus permitting objects such as Well instruments, tools, logging devices, etc., to be circulated down through the wellhead to the bottom of the well.

Another flow controlling shutolf valve, often called a swabbing valve 53, is fixedly secured to the top of the spool piece 46 so as to control the flow through the

vertical bores

47 and 48 thereof. The valve 53 is similar in design and operation to the main valve 45. The

branch conduits

51 and 52 are preferably provided with remotely-controlled

flow control valves

54 and 55 of any suitable design at a point near the spool piece, although in many installations these valves may be at the discharge end of the

conduits

56 and 57 which conduits are shown in FIGURE 1 as being connected to the

valves

54 and 55. In the event that

valves

54 and 55 were not installed next to the

branch conduits

51 and 52, then the

well fluid conduits

56 and 57 may be connected directly to the

branch conduits

51 and 52. In some Well installations, valve 45 could be omitted with a single valve 53 being employed to provide entry into the well.

When the spool piece 46 has

side conduits

51 and 52 which are curved or branched therefrom as illustrated in FIGURE 1 of the drawing, the

vertical bores

47 and 48 through the spool piece 45 are preferably provided with a pair of tubing plugs 6t and 61. The

lower end

62 and 63 of the plugs 6t) and 61 are shaped to form a uniform continuation of the inner side wall of the

conduits

51 and 52 as they merge into the

vertical bores

47 and 43 in the spool piece 46. The plugs 6 and 61 are provided with locking

dogs

64 and 65 for fixedly positioning and orienting them in place, and with

fishing necks

66 and 67 whereby a Wire line tool may be lowered through the wel head assembly and contact the fishing necks so as to withdraw the plugs from the spool piece, when desired.

Extending vertically from the swabbing valve 53 is a well entry conduit '70 having

dual bores

71 and 72 therethrough which are in register through valve 53 with thevertical bores 47 and 48 of the spool piece 46. The we'll entry conduit 70 may be closed in any suitable manner, such as for example, by a wellhead closure apparatus described in copending application, Serial No. 830,587, filed July 30, 1959. Alternatively, an extension conduit 73 (FIGURE 3) may be coupled to the well entry conduit 70 by means of a flexible coupling '74 of a type described in copending patent application Serial 7 No. 809,430, filed April 28, 1959. In'this latter case the extension conduit 73 would be of a length sufficient to extend from the top of the wellhead assembly to a point above the surface of the water thereby permitting tools, instruments or other devices to be run down the

tubes

75 and 76 within the extension conduit 75 when the latter was in a vertical position. Normally. the extension cond duit 73 would lay down so that its free end would be resting on the ocean floor. g

In order to operate the ldcking dogs 4% (FIGURE 2) of the present apparatus it is necessary that the pressure liuid be supplied through

conduits

37 and 33 to the chamher as above or below the piston 35, depending upon Whether the dogs 49 have previously been locked or unlocked. The conduits 37 and .33 upon leaving the closure body 22 are in communication with a pair of vertical conduits 77 and While it is possible for

vertical conduits

77 and 73 to be flexible in character and with a length sufiicient to extend to a point above the surface of the water, from which point operations may be carried out, it is preferred that the

dual bores

71 and 72 in the well entry conduit 7% be utilized for supplying a pressure fluid to the chamber 36 (FIGURE 2) to drive the piston 35 and actuate the locking dogs 40. Thus, the conduits 7'7 and 78 are connected into the well entry conduit 70 at a point above the uppermost flow control valve 53 so as to preclude accidental operation, by flowline pressure or other Wellhead pressures, of either or both sleeve valves '81 and 82 positioned in recessed portions '83 and 84 of the

bores

71 and 72. The internal diameter of the

sleeve valves

81 and 82 is preferably equal to that of the

vertical bores

71 and 72 in the well entry conduit 76 thereby facilitating passage of instruments, tools or other devices therethrough. The

valves

81 and 82 are of the type which may be easily shifted from an open to a closed position by means of a valve-shifting tool run on a wire line down through

vertical bores

71 and 72. A tool of this type is described in The Composite Catalog of Oil Field Equipment, 1957 edition, page 1976, FIGURES 2 and 3.

The

valves

45, 53, 54 and 55 of the present wellhead assembly may be operated by hydraulic or pneumatic pressure with individual flexible fluid pressure conduits extending from the surface of the water down to each valve on the wallhead. However, since this is a somewhat cumbersome arrangement it is preferred that the valve actuating means be positioned adjacent the wellhead with a single multi-conductor cable 83 carrying electrical signals to the various components of the valve actuating system. Preferably a container 84 surrounds the wellhead assembly, extending from the casing closure body 22 to above the swabbing valve 53, or if desired, to a point above the

sleeve valves

81 and 82. The fluid

flow handling conduits

56 and 57 extending from the container 84 are preferably flexible, or are provided with flexible joints so that they may lay down on the ocean floor. Alternatively,

conduits

56 and 57 may be rigid metallic pipes provided with suitable means for connecting them to flexible flow lines or to rigid metallic pipe flow lines. Connector means of this type are described in copending patent application, Serial No. 835,931, filed August 25, 1959.

The container or housing 84 surrounding the wellhead assembly of the present invention contains the valve actuating arrangement which may be of any suitable type Well known to the art. For purposes of illustration an electrically actuated, hydraulically-operated system is shown ernployin electrically driven

pumps

86 and 87 which deliver fluid under pressure to the various pilot valves 9P95 of the system, which valves are elec-. trically actuated and operatively connected through lead lines (not shown) to the source of power or incoming signals which come in through cable 83. Although the present invention is described with'regard to a self-contained hydraulically-operated valve actuating assembly within the housing 84, the components of the assembly may also be pneumatically or electrically operated. Since valve operating systems are well known to the art, and since they do not form part of the present invention, they will not be further described here.

In FIGURE '3 a Wellhead structure is shown as positioned within a housing 1% which in turn is supported by a suitable structural base Hi1. A pair of guidelines 102 and 163 are shown by which the equipment was originally lowered into place, as described copending patent application, Serial No. 830,538, filed July 30*, 1959. In this particular arrangement the wellhead assembly is shown as being provided with a blow-out preventer 1% which may be employed if desired.

The blow-out preventer L24 is locked down on the easinghead 11 by the equipment lock-down device comprising a casing closure body 22 having a single bore therethrough, together with locking dogs 41} and, if desired, seal ring 34, as shown in FZGURE 2. In order to move the piston 35 to lock dogs 41 the

conduits

37 and 38 would be connected to a pair of flexible conduits 1 35 and 1126 (FIGURE 3 Thus, it may be seen that the lockdown apparatus of the present invention may be employed to lock other equipment on an underwater casinghead besides the wellhead assembly shown in PEGURE 1.

While the present invention has been described with regard to a dual-tubing wellhead assembly, similar apparatus could also be used on wells having one, three or more tubing strings. in the event that a single tubing string was employed it would be necessary to modify the piston 35 which actuates the locking dogs 46 of the lock-down device. One alternate form of the lock-down device is shown in FIGURE 4 as having a body member 122 with a single bore 126" therethrough and a single conduit 137 through which a pressure fluid may be pumped to actuate the piston 135.

Pressure fiuid is supplied through conduit 137 at a predetermined pressure, say 109 p.s.i., which causes piston 135 to move downwardly. 'Ihe downwardly and inwardly sloping face 14-3 of the piston forces locking dogs 14a into the annular groove 142 and subsequently expands the sealing ring 134 against the inner surface of the body 112. Downward movement of the piston is limited by a shear pin 128 extending through a hole in the wall of the body member 122, which hole is closed by a plug 129. To unlock the locking dogs 14%), a fluid at a higher pressure, say 300 p.s.i., would be pumped through conduit 137 against the top of the piston 135, thereby supplying sufiicient force to shear the pin 328 allowing the piston 135 to move downwardly until the dogs 1% and, if desired, the packing ring 134 are opposite an annular groove 121 on the outside of piston 135. An upward pull on body member 122 would retract the dogs 1% into the groove 12K. The tool could be reset at the surface by installing a new shear pin.

In operation, if it is de d to re-enter a well to carry out some operation within the well, such for example as running a perforating gun down the well tubing string to perforate an interval of tubing therein, the extension conduit 73 (FIGURE 3) would be raised to an upright position by means of a cable, grappling hook, or other device, until the upper end thereof extends above the surface of the water. Alternatively, other conduit means could be employed to run between the bores of the wellhead entry conduit 71: and the operational base above the surface of the water. The flexible coupling 74- would be jointed together and, after closing valves 45', 5d and 55 (FIGURE 1) and opening swabbing valve '53, a wire line tool would be run in through vertical bore 71 of the wellhead entry conduit 7t; to engage the fishing neck 56 of plug 6t and withdraw it from the wellhead assembly to the surface. The same operation would be repeated in the vertical bore 72 of the well entry conduit 7i) so as to remove plug 61 therefrom. Withthe plugs db and 61 removed and tubing strings such as 75' and 76 (FIG- URE 3) installed from the surface, a perforating gum could be inserted in

conduit

75 or 76 above the surface of the water, and with valve :5 and 5'3 of the wellhead assembly open, the gun or other device could be lowered or circulated down through the conduit 73. to the bottom of the well. Fluid already in

conduits

71, 47 and 23 would be pumped down into the well to return up the

parallel conduits

24, 48 and 72 to the surface in the event that the tool was circulated down the well. To return the instrument from the bottom of the well, the circulation of fluid in

conduits

71 and 72 would be reversed with the fluid being pumped down

conduits

72, 48 and 2 to drive the instrument up conduits 23, 4-7 and 71 to the head of the well again. If the tool or instrument was short and/ or flexible, it could be circulated down into the well through conduit 5d, valve 54, side conduit 51 and valve 45.

In the event that it was found necessary to remove the wellhead assembly and the tubing strings 25 and 26 (FIG- URE 2) depending therefrom, a wire line valve shifting tool would be lowered through

vertical bores

71 and 72 of the well entry conduit 7b to shift the

sleeve valves

81 and 82 to their open position. A pressure fluid would then be pumped down through vertical bore 72, conduit 78 and conduit 38 to the space 36a below the piston to drive the piston upwardly, thus allowing the locking dogs to be retracted inwardly into the casinghead closure body 22 upon an upward pull of the entire wellhead assembly to the surface. When the wellhead assembly was again run into the well casinghead, the pressure fluid would be pumped down conduit 71 of the well entry conduit 76 and thence down through

conduits

77 and 37 to drive the piston 35 down and force the locking dogs 4% into the annular recess 42. At the same time the fluid below the piston 35 in chamber 3601 would return up through

conduits

38, 78 and 72 to the surface when both

slide valves

81 and 82 were open. After locking the casinghead closure body 22 on the casinghead, the wire line valve shifting tool is again run into

conduits

71 and 72 to close sleeve valves 81 and $2. Thereafter, a well could be put on production by opening the main valve and closing valve 53 after the tubing plugs as and d1 have been run into place.

We claim as our invention:

1. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said wellhead closure assembly comprising a casinghead closure body of a size to fit within an underwater casinghead, said closure body having substantially vertical conduit means therethrough, well tubing string means secured to the lower end of said closure body substantially coaxial with said vertical conduit means, locking means carried by said closure body for locking said closure body to the inside of said casinghead, actuating means carried by said closure body and operatively engageable with said locking means for actuating said locking means, a spool piece having substantially vertical conduit means therethrough and mounted above said closure body with said conduit means aligned with the vertical conduit means of said closure body, said spool piece having side conduit means leading from said vertical conduit means, valve means secured to the top of said spool piece for controlling fluid flow through the vertical conduit means thereof, and well entry conduit means extending vertically from said valve means in alignment through said valve means with the vertical conduit means of said spool piece.

2. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said Wellhead closure assembly comprising a casinghead closure body of a size to fit within an underwater casing-v head, said closure body having a pair of substantially vertical conduits therethrough, a pair of well tubing strings secured to the lower end of said closure body substantially coaxial with said vertical conduits outwardly-extending locking elements carried by said closure body for locking said closure to the inside of said casinghead, piston means carried by said closure body and operatively engageable with said locking elements for actuating said locking elements into locked position, a spool piece having dual substantially vertical conduits therethrough and mounted on said closure body with said conduits aligned with the vertical conduits of said 2.7 D closure body, said spool piece having side conduits leading from each of said vertical conduits, valve means secured to the top of said spool piece for controlling fluid flow through. the vertical conduits thereof, a pair of well entry conduits extending vertically from said valve means in alignment through said valve means with the vertical conduits of said spool piece, and actuating-pressure-fluid conduit means through the wall of said closure body and in communication with at least one side of said piston means for actuating said locking elements.

3. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said wellhead closure assembly comprising a casinghead closure body of a size to fit within an underwater casin head, said closure body having a pair of substantially vertical conduits therethrough, a pair of well tubing strings secured to the lower end of said closure body substantially coaxial with said vertical conduits, remotelyactuatable outwardly-extending locking elements carried by said closure body for locking said closure body to the inside of said casinghead, piston means carried by said closure body and operatively engageable with said locking elements for actuating said locking elements into locked position, first valve means secured to the top of said closure body for controlling the flow through said vertical conduits, a spool piece having dual substantially vertical conduits therethrough and mounted to said valve means with said conduits aligned through said valve means with the vertical conduits of said closure body, said spool piece having side conduits leading from each of said vertical conduits, second valve means secured to the top of said spool piece for controlling fluid flow through the vertical conduits thereof, a pair of well entry conduits extending vertically from said second valve means in alignment through said second valve means with the vertical conduits of said spool piece, first actuating pressure-fluid conduit means in communication between one or said well entry conduits and one side of said piston means for actuating said locking elements, and second actuating pressure-fluid conduit means in communication between the other well entry conduit and the other side of said piston means.

4. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said wellhead closure assembly-comprising a casinghead closure body of a size to fit within an underwater casinghead, said closure body having a pair of substantially vertical conduits therethrough, a pair of well tubing strings secured to the lower end of said closure body substantially coaxial with said vertical conduits, remotelyactuatable outwardly-extending locking dogs carried by said closure body for locking said closure body to the inside of said casinghead, piston means carried by said closure body and operatively engageable with said locking elements for actuating said locking dogs into locked position, first valve means secured to the top of said closure body for controlling the flow through said vertical conduits, a spool piece having dual vertical conduits therethrough and mounted to said valve means with said conduits aligned through said valve means with the vertical conduits of said closure body, said spool piece having side conduits leading from each of said vertical conduits, second valve means connected into each of said side conduits for controlling the flow therethrough, third valve means secured to the top of said spool piece for controlling fluid flow through the vertical conduits thereof, a pair of well entry conduits extending vertically from said third valve means in alignment through said third valve means with the vertical conduits of said spool piece, first actuating pressure-fluid conduit means in communication between one of said well entry conduits and one side of said piston means for actuating said locking dogs, second actuating pressure-fluid conduit means in communication between the other well entry conduit and the other side of said piston means, and valve means in said well entry conduits'for controlling the flow of fluid trrough' said first and second actuating-pressure fluid conduits.

5. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said head closure assembly comprising a casinghead closure body of a size to fit within an underwater casinghead, said closure body having a pair of substantially vertical conduits therethrough, a pair of well tubing strings secured to the lower end of said closure body substantially coaxial with said vertical conduits, annular seal means carried on the outside of said closure body for closing the space between said closure body and said casin head in a fluidtight manner, remotely-actuatable outwardly-extending locking dogs carried by said closure body for locking said closure body to the inside of said casinghead, piston means carried by said closure body and operatively engageable with said locking elements for actuating said locking dogs into locked position, first valve means secured to the top of said closure body for controlling the flow through said vertical conduits, a spool piece having dual vertical conduits therethrough and mounted on said valve means with said conduits aligned through said valve means with the vertical conduits of said closure body, said spool piece having side conduits leading from each of said vertical conduits, second valve means connected into each of said side conduits for controlling the flow therethrough, removable closure plug means inserted in the vertical conduits of said spool piece in a manner such that the side conduits of said spool piece remain open where they intersect said vertical conduits, third valve means secured to the top of said spool piece for controlling fluid flow through the vertical conduits thereof, a pair of well entry conduits extending vertically from said third valve means in alignment through said third valve means with the vertical conduits of said spool piece, first actuating-pressure-fiuid conduit means in communication between one of said well entry conduits and one side of said piston means for actuating said locking dogs, second actuating-pressurefluid conduit means in communication between the other well entry conduit and the other side of said piston means, wire line positionable sleeve valve means in said well entry conduits for controlling the flow of fluid through said first and second actuating-pressure-fluid conduits, a well fluid discharge flow line conduit connected to each of the side conduits of said spool piece, and fluidtight container means mounted adjacent said closure body and containing actuating means for operating said first, second and third valve means.

6. Apparatus for connecting wellhead components to an underwater casinghead of a well drilled at an offshore location, said apparatus comprising an under-water casinghead having an open upper end with recessed seating means formed in the inner surface of said casinghead below the open top thereof, a casinghead closure body of a size to fit within and extending downwardly Within said casinghead in telescopic arrangement, longitudinal conduit means extending through said casinghead closure body, at least one wellhead flow control component secured to the upper end of said casingh ead closure body in register with the conduit means thereof, remotelyactuatable outwardly-extending locking elements carried by said closure body positionable for locking said closure body to the recessed seating means on the inner surface of said casinghead, fluid-pressure-operated piston means carried by said closure body in sliding operative engagement with one portion of said locking elements for forcing said locking elements outwardly into said recessed seating means of said casinghead, first actuatingpressure-fluid conduit means through said closure body to the upper side of said piston means, and second actuating-pressure-fluid conduit means through said closure body to the lower side of said piston means, said first and second actuating pressure fluid conduit means entering said closure body from the outside thereof above the point at which the closure body and casinghead are in telescopic arrangement.

7. Apparatus for connecting wellhead components to an underwater casinghead of a well drilled at an offshore location, said apparatus comprising an underwater casinghead having an open upper end with recessed seating means formed in the inner surface of said casinghead below the open top thereof, a casinghead closure body or" a size to fit within and extending downwardly with said casinghead in telescopic arrangement, longitudinal conduit means extending through said casinghead closure body, at least one wellhead flow control component secured to the upper end of said casinghead closure body in register with the conduit means thereof, remotelyactuatable outwardly-extending locking elements carried by said closure body positionable for locking said closure body to the recessed seating means on the inner surface of said casinghead, fluid-pressure operated piston means carried by said closure body in sliding operative engagement with one portion of said locking elements for forcing said locking elements outwardly into said recessed seating means of said casinghead, radially-expansible annual seal means carried on the outer surface of said closure body adjacent said locking elements, first actuatlug-pressure fluid conduit means through said closure body to the upper side of said piston means, and second actuating pressure-fluid conduit means through said closure body to the lower side of said piston means, said first and second actuating ressure fluid conduit means entering said closure body from the outside thereof above the point at which the closure body and casinghead are in telescopic arrangement.

8. Apparatus for connecting wellhead components to an underwater casinghead of a Well drilled at an oflshore location, said apparatus comprising an underwater casinghead having an open upper end with recessed seating means formed in the inner surface of said casinghead below the open top thereof, a casinghead closure body of a size to fit within and extending downwardly within said casinghead in telescopic arrangement, longitudinal conduit means extending through said casinghead closure body, at least one wellhead flow control component secured to the upper end of said casinghead closure body in register with the conduit means thereof, remotelyactuatable outwardly-extending locking elements carried by said closure body positionable for locking said closure body to the recessed seating means on the inner surface of said casinghead, fluid-pressure operated piston means carried by closure body in sliding operative engagement with one portion of said locking elements for forcing said locking elements outwardly into said recessed seating means of said casinghead, radially-expansible annular seal means carried on the outer surface of said closure body adjacent said locking elements, first actuating-pressure-fluid conduit means through said closure body to the upper side of said piston means, second actuating-pressure-fluid conduit means through said closure body to the lower side of said piston means, said first and second actuating pressure fluid conduit means entering said closure body from the outside thereof above the point at which the closure body and casinghead are in telescopic arrangement, an outwardly-extending upwardly-tapered flange on the top of said closure body for seating said closure body on the top of said casinghead, and annular seal means carried between the seating face of said outwardly-extending flange and the top of said casinghead.

9. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said wellhead closure assembly comprising a casinghead closure body of a size to fit within an underwater casinghead, said closure body having vertical conduit means therethrough, tubing string means secured to said closure body substantially coaxial with said vertical conduit means, locking means carried by said closure body for locking said closure body to the inside of said casinghead, and actuating means carried by the closure body and operatively engageable with said locking means for actuating said locking means.

10. A wellhead lock-down apparatus comprising a cylindrical body member having an axial bore therethrough and being of a size to fit into the open upper end of a vertically-projecting tubular well member, outwardly-extending shoulder means formed on the outside of said body member, said shoulder means having a diameter greater than at least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into contact with the inner surface of said well member, and actuating means carried by said body member for operatively-engaging said locking means, said actuating means being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly of said body member into locking relation with a surrounding well member thereby preventing separation of said body member and said Well member, said body member containing pressure-fluid port means in the wall of said body member thereof through which pressure fluid is communicable to said actuating means, said port means entering said housing above said outwardly extending shoulder means.

11. A wellhead lock-down apparatus comprising a cylindrical downwardly-extending body member having an axial bore therethrough and being of a size to fit into the open upper end of a vertically-projecting tubular well member, outwardly-extending shoulder means formed on the outside of said body member, said shoulder means having a diameter greater than at least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member, said locking means carried in an inoperative recessed position by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into looking contact with the inner surface of said well member, actuating means carried by said body member for operatively-engaging said locking means, said actuating means being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly of said body member into locking relation with surrounding well member thereby preventing separation of said body member and said well member, said body member containing pressure fluid port means in the wall of said body member from the outside thereof through which pressure fluid is communicable to said actuating means, said port means entering said housing above said outwardly extending shoulder means, and annular sealing means carried outwardly by said body member for sealing off between said body member and a well member into which said body member has been positioned.

12. A wellhead lock-down apparatus comprising a cylindrical downwardly-extending body member having an axial bore therethrough and being of a size to fit into the open upper end ot a vertically-projecting tubular well member having recess means f rmed on the inner surface thereof, outwardly-extending shoulder means formed on the outside of said body member, said shoulder means having a diameter greater than at least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member, said locking means carried in an inoperative recessed position by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into said recess means on the inner surface of said well member, actuating means carried by said body member for operatively-engaging said locking means, said actuating means aces-yes being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly of said body member into locking relation with a surrounding well member thereby preventing separation of said body member and said well member, said body member containing pressure fluid port means in the wall of said body member from the outside thereof through which pressure fluid is communicable to said actuating means, said port means entering said housing above said outwardly extending shoulder means, and annular sealing means carried outwardly by said body member for sealing off between said body member and a well member into which said body member has been positioned.

13. A wellhead lock-down apparatus comprising a cylindrical downwardly-extending body member having an axial bore therethrough and being of a size to fit into the open upper end of a vertically-projecting tubular well member having groove means formedon the inner surface thereof, outwardly-extending shoulder means formed on the outside of said body member above the lower end thereof, said shoulder means having a diameter greater than at least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member below said shoulder means thereon,

said locking means carried in an inoperative recessed position by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into said groove means on the inner surface of said well member, actuating means carried by said body member and having sloping shoulder means for operativelyengaging said locking means, said actuating means being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly of said body member into locking relation with a surrounding well member thereby preventing separation of said body member and said well member, said body member containing pressure fluid port means in the wall of said body member from the outside thereof through which pressure fluid is communicable to said actuating A means, said port means entering said housing above said outwardly extending shoulder means, and annular sealing means carried outwardly by said body member for sealing off between said body member and a well member into which said body member has been positioned, said sealing means form'ing a fluidtight seal by movement of said actuating means within said body member.

14. The apparatus of claim 11 wherein said annular sealing means forms a fluidtight seal when said shoulder of said body member is seated on a co-operating landing surface of a well member.

15. A wellhead assembly comprising a tubular well member having an open end and locking recess means formed in the inner wall surface thereof at a point displaced from the open end thereof, a cylindrical downwardly-extending body member of a size to fit into the open upper end of said tubular well member in telescoping arrangement, shoulder means formed on the outside of said body member, said shoulder means having a diameter greater than that of cooperating meanscarried by said tubular well member adjacent the bore thereof for seating thereon, locking means carried by said body member, said locking means carried in an inoperative recessed position by a body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into said recess means on the inner surface of said well member, actuating means carried by said body member for operatively-engaging said locking 'means, said actuating means being movablein said body member in response to fluid pressure application thereto to move said locking means outwardly from said body member into locking relation with a surrounding well member thereby preventing separation of said body member and said well member, said body member containing i2 pressure fluid port through which pressure fluid is communicable to said actuating means said port means entering said housing above the point at which said body member is in telescopic arrangement with said well member.

16. A wellhead assembly comprising a tubular well member having an open end and locking recess means formed in the inner wall surface thereof at a point displaced from the open end thereof, a cylindrical downwardly-extending body member of a size to fit into the open upper end of said tubular well member, outwardlyexteuding shoulder means formed on the outside of sai body member above the lower end thereof, said shoulder means having a diameter greater than a least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member, said locking means carried in an inoperative recessed position by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into said recess means on the inner surface of said well member, actuating means carried by said body member for operatively-engaging said locking means, said actuating means being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly of said body member into looking relation with a surrounding well member thereby preventing separation of said body member and said well member, said body member containing pressure fluid port means through which pressure fluid is communicable to said actuating means, said port means entering said housing above said outwardly extending shoulder means, and

annular sealing means carried outwardly by said body member for sealing ofi between said body member and a well member into which said body member has been positioned.

17. An apparatus for facilitating underwater wellhead operations which in assembly comprises a verticallyprojecting tubular well member, a blow-out preventer mounted on the upper end of said tubular well member, a blow-out preventer lock-down apparatus secured to at least one end of said blow-out preventer coaxial there with, said lock-down apparatus comprising a cylindrical body member having an axial bore therethrough and being of a size to fit into the open upper end of a vertically-projecting tubular well member, outwardly-extending shoulder means carried on the outside of said body memher, said shoulder means having a diameter greater than at least a portion of the bore of said tubular well member for seating thereon, locking means carried by said body member and being bodily movable outwardly thereof so that a portion of said locking means projects beyond the surface of said body member toward and into contact with the inner surface of said well member, and actuating means carried by said body member for operativelyengaging said locking means, said actuating means being movable in said body member in response to fluid pressure application thereto to move said locking means outwardly from said body member into locking relation with a surrounding well member thereby preventing separation of said body member and said well member, said body member containing pressure-fluid port means in the wall of said body member from the outside thereof through which pressure fluid is communicable to said actuating means, said port means entering said housing above said outwardly extending shoulder means.

18. A wellhead closure assembly adapted to close an underwater well casinghead and be locked thereon, said wellhead closure assembly comprising a casinghead closure body of a size to fit within an underwater casinghead, said closure body having substantially vertical conduit means therethrough, well tubing string means secured to the lower end of said closure body substantially coaxial with said vertical conduit means, locking means carried by said closure body for locking said closure body to the inside of said casinghead, actuating means carried by said closure body and operatively engageable with said locking means for actuating said locking means, and a spool piece having substantially vertical conduit means therethrough and mounted above said closure body with said conduit means aligned with the vertical conduit means of said closure body, said spool piece having side conduit means leading from said vertical conduit means.

19. The apparatus of claim 18 including valve means connected between said closure body and said spool piece.

20. Apparatus for connecting wellhead components to an underwater casinghead of a well drilled at an otishore location, said apparatus comprising an underwater casinghead having an open upper end with recessed seating means formed in the inner surface of said casinghead be low the open top thereof, a casinghead closure body of a size to fit within and extending downwardly within said casinghead in telescopic arrangement, longitudinal conduit means extending through said casinghead closure body, at least one wellhead flow control componen secured to the upper end of said casinghead closure body in register with the conduit means thereof, remotelyactuatable outwardly-extending locking elements carried by said closure body positioned at a level to engage the recessed seating means on the inner surface of said casinghead, remotely actuatable actuating means carried by said closure body and movable into contact with said locking elements for forcing said locking elements outwardly into said recessed seating means of said casinghead, said closure body containing a chamber in which said actuating i eans are slidable and pressure fluid port means in the Wall of said body through which pressure fi id is communicable to said actuating means to actuate same, said port means entering the said housing above the point Where the closure body and casinghead are telescopic arrangement.

Reierences Qited in the file of this patent UNlTED STATES PATENTS 2,532,341 Shannon Dec. 5, 1950 2,590,688 Crain Mar. 25, 1952 2,859,773 Wallace Nov. 11, 1958 2,862,560 Bostocli et al. Dec. 2, 1958 2,874,784 Baker et a] Feb. 24, 1959 2,889,886 Gould June 9, 1959 2,983,066 Brown Sept. 8, 1959 2,962,096 Knox Nov. 29, 1960