Underwater Connections at Well Head Locations

This invention relates generally to the control of undersea well head equipment, and more particularly concerns the establishment of electrical and/or fluid pressure connections at sub-sea well head locations.

In the past, considerable difficulties and problems have been encountered in making remote electrical and fluid pressure connections at well heads on the ocean floor. Such connections are required to provide for remote control of the well head equipment such as valves, blowout preventers, accumulators, etc. In certain installations, elaborate procedures have been set up for ensuring alignment and effective interconnection of connectors in response to this relative horizontal movement; however, the equipment to effect such interconnections is complex, and retrieval procedures for such connectors become cumbersome and unreliable.

It is a major object of the invention to provide method and apparatus characterized as overcoming the above as well as other problems encountered in this environment.

Basically, and as regards the procedure contemplated by the invention, a locating means is positioned at a well head; first and second connector means are then independently lowered to the well head and downwardly received by the locating means to become accurately laterally spaced apart; and crossover third and fourth connectors are then lowered to the well head and vertically coupled to the first and second connectors for operatively interconnecting the latter via the crossover means. In this regard, a control line may extend from the surface to the first connector, and another control line may extend from the second connector to the well head equipment. Since all couplings and interconnections are made in a vertical direction, both make-up and retrieval of the connectors is greatly simplified, and connection dependability enhanced. Both electrical and fluid pressure line connections and couplings, in such vertical modes, are contemplated.

Additional objects of the inventions include the provision of apparatus for independently lowering and retrieving the first and second connectors, as well as the crossover connector means, such apparatus including guides independently lowered on control lines, the provision of retrievable pedestal means to receive the first and second connectors; and the provision of redundant or dual first and second connectors, as will be described.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which:

FIG. 1 is a plan view of a sub-sea well head installation;

FIG. 2 is a side elevation on lines 2--2 of FIG. 1;

FIG. 3 is a view like FIG. 1, but after predestal means has been installed at the well head.

FIG. 4 is a side elevation on lines 4--4 of FIG. 3;

FIG. 5 is a view like FIG. 4, but after further installation of a control connector on the pedestal means;

FIG. 6 is a plan view taken on lines 6--6 of FIG. 5;

FIG. 7 is a view like FIG. 6 but after further installation of a Christmas Tree at the well head, and associated connector means on the pedestal means;

FIG. 8 is a side elevation on lines 8--8 of FIG. 7;

FIG. 9 is a view like FIG. 7 but after further installation of a pilot control valve package on the pedestal oriented connectors;

FIG. 10 is a side elevation on lines 10--10 of FIG. 9;

FIG. 11 is an enlarged side elevational showing of the pedestal means and installed connectors;

FIG. 12 is an enlarged side elevational showing of the pilot control valve package; and

FIG. 13 is a system block diagram.

FIGS. 1 and 2 show a sub-sea well head 10 including a stub casing 11 and a horizontal base plate or platform 12 anchored to the casing, as by means of members 13 extending between and connected to the casing and corner intersections of platform members 15. Vertically extending guides including posts 16 and lines 160 are anchored at 17 to the corners of the platofrm structure, it being understood that other forms of platforms and guides may be employed. In this regard, the well head in FIGS. 1 and 2 is awaiting completion operation, in that the production packers have been set, production tubing and hangers have been run, and plugs have been left in the tubing hangers for safety purposes.

In accordance with the invention, a locating means is positioned at the well head so as to downwardly telescopically receive first and second connector means, to be described. The locating means may typically include structure such as a base 18 and dual locators such as pedestals 19 and 20 thereon and which project upwardly in laterally spaced apart relation to similarly orient the first and second connector means. In this regard, the locating means typically includes guide means for downwardly guiding the described structure, during lowering thereof, into locating position at the well head, and the guide means may comprise arms 21 integral with and extending oppositely from the base 18 for locating the latter generally mid-way between two of the guides 16a and 16b, to which the arms are operatively coupled. Thus, the arms may form or carry sockets 21a and 21b guidably or slidably receiving the posts 16a and 16b, respectively, so that the assembly including the arms, base and pedestals may be lowered to the well head position shown in FIG. 4, near the stub casing. If desired, the base 18 may be removably or otherwise locked to the platform 12 as by means of depending jaws 23 embracing a member 15, as seen in FIG. 4. A spacer 24 on base 18 seats on member 15. A lowering line connection to one or both pedestals is indicated at 25; however, the base 18 may be permanently locked to the platform.

Referring now to FIGS. 5 and 6, a first connector means, generally indicated at 26, is next lowered to the well head, with a control line 27 attached, the latter typically extending to a surface barge 28 or vessel other than the usual workover or drilling vessel 29 above the well head. Vessel 28 carries a reel or reels 30 for line 27, which may include an electrical cable 27a and/or a fluid pressure hose or conduit 27b, as indicated in FIG. 13. A line 110 may be employed to lower the first connector 26, there being a first guide arm or arms 31 attached to a coupling 90 (to be described) carried by line 110 and which releasably couples to the connector nipple 91 to be described. The arms have sockets 32 to slidably interfit the guide line elements 16 and 160.

In the example seen in FIG. 11, the first connector means 26 may include a sleeve 33 which fits downwardly over the locating pedestal, and locks thereon in the manner to be described. Note that the first connector may include a first upwardly presented electrical connector indicated at 34 and at the lower terminus of cable 27a. Merely as illustrative, the connector 34 includes upwardly extending plug pins, and is received in a receptacle 35 carried by sleeve 33 via a top mounting plate 36. The first connector may optionally include a dual electrical plug connector indicated at 34', and which has vertically separable telescopic interfit with connector 34, as via socket 37 which receives the latter. Connector 34' is received in a receptacle 35' carried by sleeve 33' via a top mounting plate 36'. Sleeve 33' seats on plate 36, as shown. Accordingly, should the upper connector 34' become inoperable for some reason, the assembly 33', 34', 35' and 36' may be removed upwardly, to disconnect socket 37 from plug 34, exposing the latter for reception of a third electrical connector in the form of a crossover socket element to be described.

Note the provision of a latch 37a carried by the connector sleeve 33 to interfit a groove 38 on the pedestal, and to be locked in that position by a locking pin 39 urged downwardly by spring 39a. Housing structure for these elements is indicated at 60-62, the pin 39 being yieldably upwardly removable to free the latch for retraction from groove 38. While the connector is being run into latching position, an interior sleeve 125 in lowered position holds latches 37a outwardly.

Referring to FIGS. 7 and 8, a second connector means, generally indicated at 40, is next lowered to the well head for removable downwardly telescopic reception by the dual structure, i.e. pedestal 20 in the example, so as to be upwardly retrievable independently of the first connector 26. In this regard, the second connector 40 may be carried or associated with well head equipment, such as a Christmas tree 41 lowered to the well head for attachment onto the stub casing 11, as via a well head connector 42. One example of the latter is described in U.S. Pat. No. 2,962,096 to Knox. The tree 41 may include production valves, blowout preventers, etc. schematically shown at 43 and 44, and guide arms 45 extending outwardly from the tree for guiding on lines 16 as via arm sockets 45a. Another arm 146 carries the second connector 40 previously referred to, at a location to telescopically interfit pedestal 20 in the same manner that connector 26 interfits pedestal 19. For example, as seen in FIG. 11, a sleeve 46 associated with connector 40 is received downwardly over the pedestal 20.

Note that the second connector may include a second upwardly presented electrical connector 50 like that at 34, at the terminus of a cable 51 extending to the Christmas tree junction box 52. Connector 50 includes contact or plug pins and is received in a receptacle 56 like that at 35, and suspended by plate 55.

The second connector may also optionally include a dual electrical plug connector indicated at 50', and which has vertically separable telescopic interfit with connector 50 via a socket 53, which receives the pins of plug 50. Connector 50' is received in a receptacle 56' carried by sleeve 46' via a top mounting plate 55'. Accordingly, should the upper connector 50' become inoperable for any reason, the assembly 46', 50', 55' and 56' may be removed upwardly to disconnect socket 53 from plug 50, exposing the latter for reception of a fourth electrical connector in the form of a crossover socket element to be described. Latching of the second connector 40 in the vertical positions shown is achieved by the well head connector attachment to the stub casing, as previously described, although there may be slight vertical and horizontal play of the second connector sleeve 46 relative to arm 146.

While electrical connections have been described in FIG. 11, it will be understood that fluid pressure connections may also, or alternatively, be established; thus, in FIGS. 11 and 13, first fluid connectors are indicated at 58, and second fluid connectors at 59, and dual fluid connectors 58' and 59' may be respectively associated with connectors 58 and 59 via conduits 140 and 141 in a similar manner as dual electrical connectors 34' and 50' are associated with connectors 34 and 50. Connectors 58 are at the lower terminus of control line 27b. Connectors 59 are connected via lines 66 with valve operators, the well head connector 42 and accumulators at the tree 41, and connectors 50 are connected via line 51 with limit switches, pressure switches and transducers at the tree, as seen in FIG. 13.

Lastly, third and fourth crossover connector means are lowered to the well head locations and coupled to the first and second connectors, respectively, for operatively interconnecting the latter, thereby establishing control of the Christmas tree equipment from the surface. See in this regard the control station 66 in FIG. 13, and to which the upper terminus of lines 27a and 27b may be transferred from the barge 28. Such third and fourth connectors means may be carried by the control package 70 seen in FIG. 10, to which guide arms 71 are connected, the arms having end sockets 72 which pass the guides 16. A connection for a lowering line is shown at 73 on arm 71 in FIG. 9.

Turning to FIG. 12, the package 70 includes a base plate 74, from which third and fourth electrical connectors in the form of sockets 75 and 76 extend to connect with first and second electrical connector plugs 34' and 50' respectively; alternatively, if these dual plugs have been removed, the connections may be made to the first and second plugs 34 and 50, respectively. Suitable guide pins may be carried by plate 74 to interfit guide receptacles on plate 36' and alternately receptacles on plate 36.

Operative connection between electrical sockets 75 and 76 may be made directly, as by a crossover cable of which cable 81a may be considered as representative; or, the operative crossover connection may be made via electronic logic of which panel or board 82 is representative. Similarly, crossover third and fourth hydraulic connections 83 and 84 on the package 70 may be connected with hydraulic connections 58 and 59, respectively, as is clear from FIG. 13, or with connections 58' and 59' as is seen in FIG. 12, and direct crossover connections may exist between connections 83 and 84, or some of the crossover connection may include pilot valves in series therewith, such valves indicated at 85 in FIG. 12. Both valves and electronic logic are shown at 85 and 82 in FIG. 13. Thus, when the package 70 is in place, the electrical and hydraulic connections between the surface control panel 66 and the tree 41 have been established.

Subsequently, the package 70 may be retrieved upwardly if desired, the second connector means 40 may be retrieved, the first connector means 26 may be retrieved upwardly, and finally the locating pedestals 19 and 20 may be retrieved.

Referring to FIG. 11, the number 90 indicates a retrieval tool operable to couple onto the nipple 91' carried by the upper or dual first connector assembly 26', for upwardly retrieving the latter. Tool 90 may be lowered to the well head on a line 110 guided by guide lines 16 and 160 via suitable guide arms 31 as described. Similarly, the lower first connector assembly 26 may be retrieved by coupling of tool 90 onto nipple 91 integral with locking pin 39. Upward displacement of the pin unblocks latch 37a, allowing it to cam out of groove 38 as the connector 26 is pulled upwardly. Shoulder 94 on pin 39 engages top plate 36 to urge assembly 26 upwardly; Similarly, shoulder 94' on pin 39' engages plate 36' to urge assembly 26' upwardly.

The numeral 92 generally designates latching structure for the upper first connector 26' which is similar to latching structure 37a, 39a, 60, 61 and 62 previously described, and to cooperate with pin 39' in a similar manner .