US3080921A

US3080921A - Underwater wellhead apparatus

Info

Publication number: US3080921A
Application number: US105981A
Authority: US
Inventors: John E Lacy
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1961-04-27
Filing date: 1961-04-27
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12
Also published as: GB948329A

Description

March 12, 1963 J. E. LACY UNDERWATER WELLHEAD APPARATUS 3 Sheets-Sheet 1 Filed April 27, 1961 LACY BY HM IS AGENT INVENTOR:

FIG. 4

March 12, 1963 J. E. LACY UNDERWATER WELLHEAD APPARATUS 3 Sheets-Sheet 2 Filed April 27, 1961 FIG. 3

FIG. 2

\NVENTOR:

J. E. LACY ls AGE March 12, 1963 J E. LACY 3,080,921

UNDERWATER WELLHEAD APPARATUS Filed April 27, 1961 3 Sheets-Sheet 3 FIG.7

ea 33 5a\ k A 2s l FIG.5

' 6| e4 33 f f 5 66 67 A a a k a a a 19 12 68 INVENTOR:

J.E. LACY F g.8 IS AGENT See new Inan attempt to locate new oil fields, an increasing "amount of well drilling has been conducted at offshore locations'such for example, as off the coasts of Louisiana, Texas and California. Asa general rule, the strings of casingin an offshore wiel-Ltogether with the tubing strings or string, extend to a point above the surface of the water where they are closed in a conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the-top of the casing strings. Methods and apparatus have recently been provided for drilling and completing a well wherein both the well casinghead and subsequently the wellhead assembly and casinghead equipment are located underwater at a depth sufficient to allow ships to pass over them. Preferably, the casinghead and the wellhead equipment are located close tothe ocean floor. In order to install equipment of this type underwater in depths greater than the shallow depth at which a diver can easily operate, it has been necessary to design entirely new equipment for this purpose. Thus, during the drilling, casing, completion and production of oil and gas wells at offshore locations which have'been drilled and completed in a manner described in copending patent application, Serial No. 830,53 8, filed July 30, 1959, and entitled Underwater Well Completion Method, various pieces of equipment have been developed.

When drilling a well by the above-identified method, a

flea-table drilling barge is located'ovcr a preselected drill site oifshore prior to commencing drilling operations. Alternatively, instead of a floating drill barge,.a floating drill platform maybeemployed, whichis. provided with aplurality of legs which are extendaible down through the water to the oceanfloor to serve as a firm footing for the barge during drilling operations.

Withan underwater wellhead support base temporarily supported in the drilling slot of the barge, preferably at a level below the operating deck thereof, a large diameter conduct-or pipeis inserted downwardly through the temporarily supported support base and positioned under the rotary table of the barge so that drilling operations may be carried out by running the drill stem and bit down through the support base and conductor pipe to the ocean floor. As the drill bit drills a hole in the ocean floor the lower end of the conductor pipe is lowered therein and may follow the drill bituntil the de-siredldepth of hole has been drilled. Whenthe drill bit and drill stem are removed from the conductor pipe in order to cement'it in the hole, the lower end of the conductor pipe is off tl'le bottom of the hole adistance at least equal to the distance between the temporarily supported wellhead support base on the barge and the bottom .of the body of water on which the support base is to be positioned. At this time the upper'end of the conductor. pipe has a casinghead attached toit which i-sin turn fixedly securedto the wellheadsupport base, normally by welding. With the sup- :port base fixedly secured to the casinghe'ad and conductor string, the entireassembly-is lowered in any suitable manner, as by'hoist' lines or a running. pipe string, down i to. the ocean. floor after "which cementing. operations can be carried out;

The equipment in drillingunderwater we ls 3,080,921 Patented Mar. 1 2, 1953 tremendous in size and weight and ditficult to handle at:offshorellocations, especially on a floating drill barge. For example, one un-derwaterwellhead support base, including the guide system rigidly secured thereto, was 16 feet in diameter, about 30 feet high and weighed 34,000 pounds. This support structure was temporarily positioned, during preliminary drilling operations, on the lower deck of a'drilling barge. It' was found to be extremely difficult and time-consuming to makethe necessary connections by welding components together at the side of the operation. Yet, due to the size of the equipment the component parts thereof could not be welded together previously and then transported to an offshore drilling location. I

Iris-therefore, a primary object of the present invention to provide apparatus whereby a well casinghead may be quickly and positively secured to a wellhead support structure.

A further object of the present invention is to provide apparatus of simple design which isself-actuating whereby a well casinghead and a wellhead support structure are quickly coupled together'whether the wellhead support base is positioned on a drilling barge or on the ocean iloor. These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein: Y

FlGURE l is a diagrammatic view illustrating an offshore barge fixedly positioned at a drilling location with the legs of the barge extending downwardly tothe ocean floor; I

FIGURES 2 and 3 are diagrammatic views illustrating a conductor pipe depending from a fioatable barge and the wellhead support frame and conductor pipe being lowered to the ocean floor;

FIGURE 4 is a view taken in longitudinal cross-section of one form of a casinghead when secured to a wellhead support member;

. FiGURE 5 'is a view taken in vertical cross-section of the clamping and anchoring means employed in th present invention; 7

FIGURE 6 is a view taken in vertical cross section of another form of the anchoring and clamping means of the present invention;

FIGURE 7 is a plan view taken in horizontal cross-sec the present invention.

Referring to FIGURE 1 of the drawing, any suitable type of offshore barge is schematically illustrated as having an operating deck 11 through which a series of

legs

12 and 13 extend'downwardly to the ocean floor and are adapted to be raised therefrom at a later date by means of

suitable elevator devices

14 and 15 of the type described in Composite Catalog of Oil Field Equipment, 25th Edition, p, 4814. The barge deck 11 is provided witha rotary table 16 and a derrick 17 positioned thereabove, as well as the other auxiliary equipment needed to drill a well. Extending downwardly from the barge deck 11 are a series of

braces

20, 21, 22 and 23 having suitable

removable support members

24 and 25 attached "thereto for supporting a wellhead support base 26.

surface thereof, with at least a pairof clamping and anchoring devices 31 and 32 which are positioned on opposite sidesofa hole centrally located andextending verti' cally through t'he wellhead-support base 26. The clamping and anchoring devices 31 and 32 are adapted to be fixedly secured to the wellhead support base 26. A casinghead 33 having a conductor pipe 34 depending therefrom is shown in FIGURE 4. As shown in FIGURE 4,

guide cables

34 and 35 extend downwardly through the

guide columns

27 and 28 and are fixedly secured to the bottom thereof by means of

anchor pins

36 and 27. The casinghead 33 may be provided with a side outlet valve 40 for controlling the flow of fiuid through a cement or kill line 41. The upper end of the casinghead 33 may be provided with a peripheral groove 43 by which other elements may be connected to the casinghead. Additionally, the casinghead may be provided with one or

more landing surfaces

44, 45 and 46 formed on the interior wall thereof.

In FIGURE 2 a fioatable barge 48 is illustrated as being provided with derrick 49 positioned over a drilling slot 59 in the barge in which a wellhead support member and base 26 is supported in any suitable manner, as by means of

hoist lines

51 and 52. Projecting upwardly from the support base 26 is an open-top tank 53 which contains the

guide columns

27 and 28, as described with regard to FIGURE 4. In FIGURE 2 the conductor pipe 34 is shown as having been run nearly all the way to the wellhead support base 26 but prior to having the casinghead 33 (FIGURE 4) attached thereto. In FIGURE 3 a pair of winches 54 and 55 are shown as

unreeling lines

51 and 52 to lower the Wellhead support structure 26 to the ocean floor. Alternatively, instead of using the

hoist lines

51 and 52, a running pipe 56 may be attached at its lower end at the top of the casinghead 33 so that the entire structure may be lowered by the pipe string.

Each of the clamping and anchoring devices 31 and 32 of FIGURE 1 comprises a housing 57 (FIGURES 5 and 7) which is fixedly secured to the wellhead support base 26, as by welding, at a point adjacent the central hole 29 in the base 26. Slidably mounted within the housing 57 and extcndible therefrom along a line forming the radius of the hole 29 in the support base 26 is a plate-like latch member 58. Preferably, the leading surface of the latch 58 is curved with a radius substantially equal to the outside surface of the casinghead 33. One or

more springs

60, 61 and 62 are positioned within the latch housing 57 for urging the latch 58 outwardly therefrom. Guide pins 63, 64 and 65 serve to support the

springs

60, 61 and 62 and extend through the back wall of the latch housing 57. At least one of the guide pins 64 is threaded at its outer end and provided with a take-up nut 66 so that the latch 58 may be held within the housing 57 in an inoperative position prior to use. Preferably, the upper edge 67 of the latch 58 is beveled outwardly and downwardly so that the latch 53 will be forced into its housing 57 when a weight is applied to the leading edge of the latch. The housing 58 is also provided with a landing surface 63 to conform with a seating surface carried on the lower edge of a cooperating shoulder member 70 which is secured or formed on the outside of the casinghead 33. It is to be understood that the horizontal surface of the wellhead support base 26 may also form the landing surface for the shoulder member 70.

Preferably, the shoulder member 70, carried outwardly on the casinghead 33, is in the form of a peripheral flange (FIGURE 7) but it is to be understood that the shoulder member may be merely portions of a flange, the portions being of a size which would be engaged by the latch 58. At least two latches are to be employed whichare preferably diametrically opposite each other. However, additional latches may be employed which would be normally arranged so that the latches were equally spaced one from another.

In the arrangement shown in FIGURE 5 and 7 the lower face of the shoulder member 70 forms the seating surface for the casinghead 33 while the upper surface of the shoulder member forms a latch-receiving element for engaging the latch members 58 whereby the casinghead or any other suitable well member is locked to the Wellhead support base to prevent axial separation of the casinghead or well member from the support base. Another arrangement of a latch-receiving element is illustrated in FIG- URE 6 wherein the outer wall of the casinghead 33 is provided with a plurality of recesses 71 cut or formed in the thick wall of the casinghead. These latch-receiving recesses 71 may take the form of a peripheral groove cut in the outer surface of the casinghead 33.

In another arrangement of the latching device, as illustrated in FIGURE 8, the leading edge of the latch element 58 is beveled in both directions, with a top bevel 67 and a bottom bevel 72. The dimensions of the beveled leading edge of the latch 53 are selected so that the lower beveled edge 72 contacts the upper edge of the shoulder element 70 before the leading point of the latch 58 contacts the outer wall of the casinghead 33. It is to be understood that the upper bevel 67' in this arrangement could be omitted with a flat top being used instead in the event that the latching elements were to be set by hand prior to lowering the supportbase and the casinghead into the water. However, when an upper beveled face 67 is em- .ployed in the latch 58 it is possible to have the latches in their extended operative position prior to latching onto a casinghead. Thus, in the event that the wellhead support member was positioned on the ocean floor a casinghead in accordance with the present invention could be lowered through the water so as to become automatically latched onto the support base since the weight of the casinghead and the conductor string attached thereto would be sufficient to force the latches 58 into their housings until the shoulder element 70 was seated on the landing surface 68. Normally, however, the casinghead and wellhead support member are latched together on the drilling barge prior to lowering them to their position on the ocean floor. By providing latching means in accordance with the present invention it is possible to run the casinghead through the rotary table prior to connecting it to a wellhead support member.

I claim as my invention:

1. An underwater wellhead apparatus adapted to be positioned on the ocean floor, said apparatus comprising a wellhead support base having a hole therethrough, a tubular well member extending through the hole in said support base, at least the upper portion of said well member forming at least a portion of a casinghead for a well, laterally-extending seating means carried outwardly on said well member, said seating means together with said well member projecting over a length greater than the diameter of said support base hole, a plurality of anchoring means fixedly secured to said support base adjacent the hole therethrough and around the periphery thereof, latch means carried by said anchoring means, and latch-receiving means carried on the outer surface of said well member and positioned for registering with and engaging said latch means whereby said well member and said support base are locked to prevent axial separation of said well member and said support base.

2. An underwater wellhead apparatus adapted to be positioned on the ocean floor, said apparatus comprising a wellhead support base having a hole therethrough of a diameter larger than the diameter of the largest pipe section to pass therethrough, a tubular well member extending through the hole in said support base, at least the upper portion of said well member forming at least a portion of a casinghead for a well, laterally extending seating means carried outwardly on said well member, said seating means on opposite sides of said well member together with said well member projecting over a length greater than the diameter of said support base hole, a plurality of anchoring means fixedly secured to said support base adjacent the hole therethrough and around the periphery thereof, laterally-movable latch means carried by said anchor" ing means, and latch receiving means carried. on the outer surface of said well member and positioned for registering with and engaging said latch means whereby said well member and said support base are locked to prevent axial separation of said well member and said support base.

3. An underwater wellhead apparatus adapted to be positioned on the ocean floor, said apparatus comprising a wellhead support base having a hole theretnrough of a diameter larger than the diameter of the largest pipe section to pass therethrough, a casinghead and a well casing depending therefrom extending through the hole in said support base, laterally-extending seating means carried outwardly on said casinghead, said seating means on opposite sides of said casinghead together with said well member projecting over a length greater than the diameter of said support base hole, a plurality of anchoring means fixedly secured to said support base adjacent the hole therethrough at substantially equally spaced intervals around the periphery thereof, laterally-movable spring-loaded latch means carried on said anchoring means, and latch receiving means carried on the outer surface of said casinghead and positioned for registering with and engaging said latch means whereby said casinghead and said support base are locked to prevent axial separation of said casinghead and said support base.

4. An underwater wellhead apparatus adapted to be positioned on the ocean floor, said apparatus comprising a wellhead support base having a centrally located hole therethrough of a diameter larger than the diameter of the largest pipe section to pass therethrough, a tubular well member extending through the hole in said support base, at least the upper portion of said well member forming at least a portion of a casinghead for a well, laterally extending seating means carried outwardly on said well memher, said seating means on opposite sides of said well member together with said well member projecting over a. length greater than the diameter of said support base hole, a plurality of anchoring means fixedly secured to'said support base adjacent the hole therethrough at substantially equally spaced intervals around the periphery thereof, said anchoring means having landing means formed thereon for cooperating with the outwardly extending seating means on said well member, laterally-movable springloaded latch means carried by said anchoring means, and latch receiving means carried on the outer surface of said well member and positioned for registering with and engaging said latch means whereby said well member and said support base are locked to prevent axial separation of said well member and said support base.

5. An underwater wellhead apparatus adapted to be positioned on the ocean floor, said apparatus comprising a wellhead support base having a centrally located hole therethrough of a diameter larger than the diameter of the largest pipe section to pass therethrough, a tubular well member extending through the hole in said support base, at least the upper portion of said well member forming at least a portion of a casinghead for a well, a laterally-ex? tending seating flange carried outwardly on said well memher, said seating flange extending around said well member and being of a diameter greater than the diameter of said support base hole, a plurality of anchoring means fixedly secured to said support base adjacent the hole therethrough at substantially equally spaced intervals around the periphery thereof, said anchoring means having landing surfaces formed thereon for cooperating with the outwardly extending seating flange on said well member, laterally-movable spring-loaded latch means carried on said anchoring means, and the outwardly extending edge of said latch means having top and bottom bevels, and a latch-receiving downwardly beveled surface formed on the seating flange for registering with and engaging said latch means whereby said well member and said support base are locked to prevent axial separation of said well member and said support base.

References Cited in the file of this patent Word Feb. 6, 1962

Claims

1. AN UNDERWATER WELLHEAD APPARATUS ADAPTED TO BE POSITIONED ON THE OCEAN FLOOR, SAID APPARATUS COMPRISING A WELLHEAD SUPPORT BASE HAVING A HOLE THERETHROUGH, A TUBULAR WELL MEMBER EXTENDING THROUGH THE HOLE IN SAID SUPPORT BASE, AT LEAST THE UPPER PORTION OF SAID WELL MEMBER FORMING AT LEAST A PORTION OF A CASINGHEAD FOR A WELL, LATERALLY-EXTENDING SEATING MEANS CARRIED OUTWARDLY ON SAID WELL MEMBER, SAID SEATING MEANS TOGETHER WITH SAID WELL MEMBER PROJECTING OVER A LENGTH GREATER THAN THE DIAMETER OF SAID SUPPORT BASE HOLE, A PLURALITY OF ANCHORING MEANS FIXEDLY SECURED TO SAID SUPPORT BASE ADJACENT THE HOLE THERETHROUGH AND AROUND THE PERIPHERY THEREOF, LATCH