Underwater Pipe Connection Apparatus

Abstract

A flowline guide structure is lowered from a floating vessel along selected guide lines extending upwardly from the guide post of a previously installed standard guide structure suitably mounted at the upper end of a well bore drilled downwardly from the floor of an ocean or other body of water, the selected guide lines determining the direction in which flowlines are to extend, and which are to be secured to the flowline guide structure and appropriately aligned with flowline loops extending from a Christmas tree lowered along the guide lines and then connected to the wellhead, the flowlines being secured to the flowline loops in leak-proof relation.

Description

The present invention relates to underwater pipe connection apparatus, and more particularly to apparatus used in effecting a connection between the flowlines of an underwater Christmas tree connected to a wellhead and flowlines extending laterally through the water from the well and Christmas tree.

Prior systems for completing and producing underwater wells have required the use of a comparatively expensive guide structure mounted at the underwater floor, and from which guide lines extend upwardly to a floating drilling vessel, such guide structure not only serving during the drilling of the well, but including auxiliary equipment used subsequently for guiding the Christmas tree into appropriate position for connection to the wellhead, and also as a means for pulling in and connecting flowlines to the flowline loops extending from the Christmas tree. At the time of lowering and anchoring the guide structure in place, the proper direction for pulling in the flowlines had to be known, so that the Christmas tree and flowline loops could be oriented in the proper direction. Since only a small percentage of exploratory well bores drilled become commercial producers, an expensive guide structure was previously provided for routine drilling of a well, despite the fact that the additional facilities provided on such guide structure were not used in the event the drilled well bore was deemed to be non-commercial.

One of the purposes of the present invention is to permit a standard and less expensive guide structure to be used in connection with the drilling of an underwater well. After the well has been drilled and the formations encountered have been tested, which determine the well to be a commercial producer, a determination can be made of the type of completion required, including a determination of the most advantageous layout of flowlines to be connected to the Christmas tree and the direction in which the flowlines should be run from the well.

After making the determination of the direction from the well the flowlines should extend, a flowline guide structure can be lowered down selected guide lines and onto selected guide posts of the standard guide structure, this flowline guide structure including a flowline alignment assembly. The Christmas tree, with the flowline loops secured thereto, can be oriented and lowered down the guide lines and onto the guide posts of the standard guide structure and into coupled relation with the wellhead, at which time the end portions of the flowline loops will be appropriately related to the flowline hub alignment assembly. The flowlines can be moved downwardly and the end portions thereof secured to the flowline hub alignment assembly in alignment with the Christmas tree hub, such parts then being coupled together in leakproof relation. Such coupling can be effected through the assistance of a diver, or it might be effected without diver assistance, the latter usually being accomplished where the water depth is greater than diver depth.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIG. 1 is an isometric view of a guidance structure disposed at a subsea floor, with a flowline guide structure secured thereto, and a Christmas tree also disposed in position on the guidance structure;

FIG. 2 is an enlarged section taken along the line 2--2 on FIG. 1;

FIG. 3 is a vertical section taken along the line 3--3 on FIG. 2;

FIG. 4 is a view similar to FIG. 1 disclosing a guide funnel assembly releasably secured to the flowline guide structure, and with flowlines being pulled toward the funnel assembly;

FIG. 5 is a side elevational view illustrating the flowlines adjacent to the flowline guide structure and in position to be coupled thereto;

FIG. 6 is a view similar to FIG. 5 illustrating a hub connected to the flowline and the Christmas tree hub coupled together in leakproof relation;

FIG. 7 is an enlarged view taken along the line 7--7 on FIG. 6, disclosing the releasable pivotal connection between the flowline carrier and the flowlines;

FIG. 8 is an enlarged fragmentary section taken along the line 8--8 on FIG. 6;

FIG. 9 is an enlarged vertical section taken along the line 9--9 on FIG. 6;

FIG. 10 is a section taken along the line 10--10 on FIG. 9;

FIG. 11 is an enlarged section taken along the line 11--11 on FIG. 5;

FIG. 12 is a section taken along the line 12--12 on FIG. 11;

FIG. 13 is a side elevational view of a power device for shifting the Christmas tree hub toward and into engagement with the flowline hub.

In the drilling of a well bore W from the floor 10 of an ocean or other body of water, a known and standard guide structure 11 is secured at the floor of the ocean at the time of spudding the well, this guide structure being suitably secured to the ocean floor. It includes a central hub 12 to which diagonal beams 13 are secured, side beams 14 being disposed between and suitably attached, as by welding, to the outer portions of the diagonal beams. A guide post 15a, 15b, 15c, or 15d extends vertically upwardly from each diagonal beam 13, guide lines 16a, 16b, 16c, 16d being secured to the guide posts and extending upwardly to the drilling platform or drilling vessel (not shown) from which the well bore is drilled. In connection with drilling the well bore W, a wellhead housing 17 is disposed within the central hub 12 and is suitably secured thereto, this wellhead housing 17 being all that is allowed to remain above the hub 12 after the well bore has been drilled, and preparatory to the running of a Christmas tree structure 18 into position, followed by the connection of its flowline loops 19 to flowlines 20 (FIGS. 4-6) that will extend laterally from the Christmas tree and the wellhead housing 17, as described hereinbelow.

After a determination has been made of the direction the flowlines 20 are to extend from the well, a flowline guide structure 21 is lowered down a selected pair of guide lines or cables 16a, 16b and onto their companion guide posts 15a, 15b. This flowline guide structure includes vertical sleeves 22a, 22b spaced horizontally from one another a distance corresponding to the spacing between a pair of guide posts 15a, 15b, these sleeves having lower guide cones 23 secured thereto for guiding the sleeves over the upper tapered ends 24 of the guide posts and onto the main cylindrical portions 25 of the guide posts therebelow. The sleeves 22a, 22b and cones or funnels 23 are welded, or otherwise suitably secured, to an intervening cross structure 26 that includes upwardly extending portions or arms 27 spaced from one another, the inner portion of the arms being suitably secured to flowline hub alignment members 28 spaced from and looking toward each other. Each flowline member 28 has its marginal portions bevelled in an outward direction, to provide tapering or inclined guide surface 29 for other devices described hereinbelow.

The members 28 have inner horizontal lock grooves 30 facing toward each other, there being upper outwardly directed horizontal flanges 31 at the upper end of each member, each flange having a vertical slot 32 therethrough diverging in an outward direction. The flowline hub alignment members 28 are spaced a predetermined distance apart and are located on the cross member 26 of the guide structure 21 closer to one of the vertical guide sleeves 22b than the other of the vertical guide sleeves 22a, so that the mid-point between the plate members 28 is offset laterally from a vertical radial plane of the wellhead housing 17.

The flowline guide structure 21 is lowered down selected guide cables 16a, 16b and over a corresponding selected pair of guide posts 15a, 15b until the lower ends of the guide cones 23 and cross member 26, which may be located in the same horizontal plane, come to rest upon a guide beam 14. A suitable cable 35 may be used for lowering the guide structure 21 to the position described. Upon engaging the standard guide structure 11, the flowline guide structure 21 is locked to the latter by means of latches 36 (FIGs. 2, 3) pivotally mounted on the flowline guide structure, each latch having a tapered guide nose 37 which terminates at its upper portion in a latch dog 38, the tapered guide surface 37 engaging the upper flange 39 of a guide beam 14 which deflects it outwardly until the latch dog passes below the upper flange 39, whereupon gravity of a spring 40 biases the latch inwardly to position the dog 38 under the flange, thereby preventing upward movement of the flowline guide structure 21 relative to the standard guide structure 11.

Before the flowline guide structure 21 is lowered down a pair of guide lines and along associated guide posts, a determination has been made of the direction that the flowlines 20 are to extend with respect to the wellhead housing 17 and the Christmas tree 18 to be connected thereto. Any two adjacent guide lines and guide posts connected thereto can be selected along which the flowline guide structure 21 is to be lowered, depending upon the direction in which the flowlines 20 are to extend relative to the well. Thus, as specifically disclosed, any one of four different directions can be selected, the lines 16a, 16b and posts 15a, 15b having been selected by way of illustration.

After the flowline guide structure 21 has been lowered and locked in place, an upward pull is taken on the line 35 of sufficient magnitude as to disrupt shear pins 35a, or the like, releasably securing the line 35 to the guide structure, permitting removal of the line 35 to the drilling vessel. The Christmas tree structure 18 is then lowered down the guide lines 16a- 16d, properly oriented so that its flowline loops 19 will be placed in alignment with the hub alignment assembly members 28 after the Christmas tree has been landed and locked in place. As specifically disclosed, the Christmas tree structure has a suitable guide frame 40 secured thereto, which, as specifically disclosed, consists of radial arms 41 attached to a central member 42, the outer ends of the arms being attached to guide funnels 43 corresponding in number and relative spacing to the number and spacing of guide posts 15a-15d. The Christmas tree has one or a plurality of flowline loops 19 attached thereto that pass through a housing 44 and terminate in a hub or connector 45 extending laterally of the central member 42 of the Christmas tree assembly, the housing being slidable longitudinally in an encompassing guide 46 spaced from and suitably affixed to the central member of the Christmas tree. The Christmas tree is lowered on a suitable running string (not shown), with the end portions of the flowline loops 19 and the tree hub 45 oriented in the same direction as the flowline hub alignment assembly member 28, lowering of the tree continuing until the guide funnels 43 pass over the guide posts 15a-15d and with a central connector of a known type at the lower end of the Christmas tree assembly being received within the wellhead housing 17 and appropriately latched thereto in leakproof relation. When this occurs, the tree hub 45 is aligned with the flowline hub alignment assembly members 28, the hub 45 being spaced horizontally from such assembly.

After the Christmas tree 18 has been landed and latched in place, the flowlines 20 are to be lowered through the water and connected to the flowline loops 19 of the Christmas tree assembly. As specifically disclosed, an apparatus is provided for feeding the flowlines from a pipe laying barge (not shown) floating in the body of water, and pulling the flowlines inwardly toward the flowline hub alignment assembly 21. Prior to lowering the flowlines 20 from the pipe laying barge, a guide funnel assembly 50 is provided (FIG. 4), which includes a pair of guide funnels 51 held in spaced relation a distance equal to the spacing between a pair of guide posts 15a, 15b by a cross structure 52 suitably affixed thereto, this cross structure carrying a pair of guide funnels 53 extending parallel to each other and inclined in an upward and outward direction. The cross structure carries a pair of depending keys 54 adapted to be received in the key slots 32 in the side member flanges 31, there being a latch 55 pivotally mounted on each key and having a lower lock dog 56 adapted to fit under a side member flange 31 to releasably secure the guide funnel assembly 50 in a downward position. A helical compression spring 57 urges its guide dog 56 in an inward direction; whereas, a release cable 58 interconnects the upper portions of the latches above their pivot pivot points 59, which is pulled upwardly to pivot the upper portions of the latches inwardly toward each other and their dog portions 56 in directions outwardly from each other and against the compression of their associated springs 57 to release the latch dogs from the flanges 31 of the alignment assembly when the guide funnel assembly 50 is to be released from the flowline guide structure 21, as described hereinbelow. Such release can be effected by taking an upward pull on a cable 60 secured to the release cable 58 and extending to the drilling vessel.

The ends of the flowlines 20 pass through and are suitably connected to a flowline support 61, the upper portion of which is pivotally connected to lugs 62 projecting from a cross member 63 from which parallel alignment probes 64 extend. A pivot pin 65 (FIG. 7) extends through and is threaded in each lug 62, its cylindrical head 66 being piloted into a companion bore 67 in the flowline support, such that the flow line support 61 and the flowlines 20 attached thereto can pivot with respect to the cross member 63 and the alignment probes 64 projecting forwardly therefrom. The flowlines also terminate in a flowline connection assembly or hub 20a that is to be pulled toward and connected to the flowline hub alignment assembly 28, as described below.

A pulling line 68 is attached to the forward tapered end portion of each alignment probe 64, each of the pulling lines extending into an associated guide horn 53, each pulling line extending around a sheave 69 rotatably mounted on the funnel assembly structure 50, the lines then passing over another sheave 70 rotatably mounted on the funnel assembly structure (FIGS. 5, 6), continuing onto a winding drum 71 suitably supported on the funnel structure 50 and rotatable by a suitable hydraulic motor and gearing 72 (not specifically detailed). If desired, the pulling lines 68 could pass around the sheaves 69 upwardly to a platform above the well bore W, or to a vessel floating in the water above the well bore.

The flowline hub 20a has horizontal grooves 73 in its sides in which locking keys 74 are disposed, urged outwardly by helical compression springs 75 bearing against the base of each groove 73 and encircling cap screws 76 passing through the keys and which limit the outward movement of the keys with respect to its groove 73. The keys 74 are adapted to fit within the grooves or keyways 30 in the side members 28 of the hub alignment assembly 21.

The pulling lines 68 are threaded through the funnels 53 and around their sheaves 69, 70 at the surface of the water and prior to the flowlines 20 being lowered from the pipe laying barge into the water. The guide funnel assembly 50 can then be lowered along the guide lines 16a, 16b toward the guide posts 15a, 15b, one or more lowering cables 77 being secured to the cross structure 52. The funnel assembly 50, with the pulling lines 68 extending through the guide horns 53 and around the sheaves 69, 70 and winding drum 71, is lowered into position on the running cables 77 until the keys 54 enter the grooves 32 in the flanges 31, the noses 79 of the latches 55 being first forced outwardly by the flanges 31 and the springs 57 then shifting the dogs 56 of the latches under the flanges 31 to releasably secure the guide funnel assembly 50 to the flowline guide structure 21.

The diver then appropriately causes the hydraulic motor 72 to be operated, which effects rotation of the drum 71 and the winding of the pulling lines 68 thereon, the pulling action occurring while the flowlines 20 are being played out from the pipe laying barge, the flowlines being retained in tension as the barge moves through the water in a direction away from the well W. The winding of the pulling lines 68 continues until the alignment probes 64 enter the funnels 53, continued inward pulling causing the flowline hub 20a to be disposed between the opposed members 28 of the alignment assembly, the alignment probes coming to rest when fully received within the guide horns or funnels 53. The continued lowering of the flowlines 20, as the pipe laying barge moves away from the well bore, causes the flowline support 61 and the flowline hub 20a to pivot about the pivot pins 65 until the keys 74 on the flowline hub are aligned with the grooves 30, the spring 75 snapping the keys into the grooves 30, at which time the flowline hub 20a is in appropriate alignment with the tree hub 45, the latter being spaced a short distance from the flowline hub.

The diver now removes the pivot pins 65 by unthreading them outwardly from the bores 67, disconnecting the cross member 63 from the flowline support 61. An upward pull is now taken on the release cable 60 to pull upwardly on the flow line flange release cable 58 and pivot the upper ends of the latches 55 inwardly toward each other and the latch dogs 56 outwardly from under the flanges 31, to unlock the guide funnel assembly 50 from the flowline guide structure 21. Upward movement of the cables 77 will now elevate the guide funnel assembly 50, with the alignment probes 64 disposed in the guide horns 53, upwardly from the guide posts 15a, 15b and along the guide lines 16a, 16b to the drilling vessel.

The diver now shifts the tree hub 45 toward the flowline hub 20a aligned therewith. Such shifting can be effected by use of a power cylinder 80 containing a piston 81 and piston rod 82 therein. The cylinder has a yoke 83 secured to one end, the rod having a yoke 84 secured to its end at the opposite portion of the power structure. One yoke 84 is placed over a pin 86 secured to the tree housing 44 and the other yoke 83 is placed on a pin 85 secured to the guide 46. The introduction of fluid under pressure into the head end of the cylinder 80 causes the yokes 83, 84 to move apart, which shifts the tree hub 45 toward the flowline hub 20a, there being suitable inclined tapered guides 87 secured to the tree hub 45 engaging the upper and lower edges of the flowline hub 20a, the sides of the tree hub engaging the inclined faces 29 of the hub alignment members 28 to insure the engagement of the tree hub with the flowline hub 20a in proper aligned condition, and with screws 88 disposed in the tree hub in alignment with threaded holes 89 in the flowline hub 20a. The tree hub 45 is free to move toward the flowline hub 20a, in view of the sliding of the housing 44 within the guide 46, the loops 19 flexing sufficiently without damage to permit such movement to occur.

The flowline loops 19 communicate with and are aligned with passages 90 in the tree hub, the flowlines 20 also being aligned with companion passages 91 in the flowline hub 20a. The flowline hub carries a seal ring 92 surrounding each of its passages, the tree hub having companion end grooves 93 adapted to receive such seal rings. When the tree hub 45 has been brought into engagement with the flowline hub 20a, the seal rings 92 are received within the companion seal grooves 93 in the tree hub. The diver now threads the screws 88 into the threaded holes 89 and tightens them to firmly secure the tree hub to the flowline hub, and with the seal rings 92 forced within the seal grooves 93 and in sealed relation therewith, as well as with the flowline hub 20a.

The power cylinder 80 can be removed after threading and tightening of the screws 88 into the flowline hub, the screws being readily accessible to the diver.

It is, accordingly, apparent that an apparatus has been provided in which a standard guide structure can be employed, thereby effecting substantial cost savings. After the well has proved to be commercial, the flowline guide structure 21 can be lowered along an appropriate pair of guide lines to place the flowline hub alignment assembly in the proper direction for the subsequent connection of the flowline 20 to the flowline loops 19 extending from the Christmas tree. The flowline hub 20a is appropriately related to the hub alignment assembly 28 and is locked thereto in alignment with the tree hub 45, after which the tree hub 45 and flowline hub 20a are coupled to one another in leakproof relation. The mechanism 50 for guiding the flowlines 20 and the flowline hub 20a toward the hub alignment assembly 21 is releasably latched to the flow line guide structure 21 and can be released and removed for subsequent use on another well.

Although the Christmas tree assembly 18 has been described as being lowered into position before lowering of the guide assembly 50 into position, the latter can, if desired, be lowered into position first and the flowlines 20 and hub 20a pulled into and coupled to the alignment members 28, the assembly 50 then being removed and the Christmas tree run into place.

Claims

I claim:

1. In apparatus wherein a guidance system is disposed at and extends upwardly from the floor of a body of water and through which a well bore has been drilled into the underlying formation, the combination therewith of a flowline guide structure movable downwardly along said system to a predetermined position, flowline alignment means secured to said flowline guide structure, fluid flow apparatus including one or more first flowlines and lowered along said system into communication with the well bore with end portions of said one or more flowlines facing said alignment means, one or more second flowlines adapted to be lowered through the body of water, after said flowline guide structure has been lowered to said predetermined position, connector means secured to said one or more second flowlines and engageable with said alignment means to position said connector means in alignment with said end portions of said one or more first flowlines, guide means adjacent to and disposed to one side of said flowline alignment means, means operatively connected to said guide means for moving said connector means and one or more second flowlines toward said guide structure to engage said connector means with said alignment means, and means for operatively connecting said one or more first flowlines and one or more second flowlines to each other, whereby fluid can flow therebetween.

2. In apparatus wherein a guidance structure is disposed at and extends upwardly from the floor of a body of water and through which a well bore has been drilled into the underlying formation, the guidance structure including upwardly extending guide posts and guide lines extending upwardly from the posts, the combination therewith of a flowline guide structure movable along one or more selected guide lines and over one or more guide posts connected thereto, flowline alignment means secured to said flowline guide structure, fluid flow apparatus including one or more first flowlines and lowered down the guide lines and over the guide posts into communication with the well bore with end portions of said one or more flowlines facing said alignment means, one or more second flowlines adapted to be lowered through the body of water after said flowline guide structure has been moved over said one or more guide posts, connector means secured to said one or more second flowlines and engageable with said alignment means whereby said connector means is positionable in alignment with said end portions of said one or more first flowlines, guide means adjacent to and disposed to one side of said flowline alignment means, means operatively connected to said guide means for moving said connector means and one or more second flowlines toward said guide structure to engage said connector means with said alignment means, and means for operatively connecting said one or more first flowlines and one or more second flowlines to each other, whereby fluid can flow therebetween.

3. In apparatus as defined in claim 2; and means for securing said flowline guide structure to said guidance structure.

4. In apparatus as defined in claim 2; and means for securing said connector means to said alignment means, whereby said connector means will be in alignment with said end portions of said one or more first flowlines.

5. In apparatus as defined in claim 2; means for securing said flowline guide structure to said guidance structure; and means for securing said connector means to said alignment means in alignment with said end portions of said one or more first flowlines.

6. In apparatus as defined in claim 2; said connecting means including means for shifting said one or more first flowlines toward said connector means.

7. In apparatus as defined in claim 2; means for securing said flowline guide structure to said guidance structure; and means for securing said connector means to said alignment means in alignment with said end portions of said one or more first flowlines, said connecting means including means for shifting said one or more first flowlines toward said connector means.

8. In apparatus wherein a guidance system is disposed at and extends upwardly from the floor of a body of water and through which a well bore has been drilled into the underlying formation, the combination therewith of a flowline guide structure movable downwardly along said system to a predetermined position, flowline alignment means secured to said flowline guide structure, fluid flow apparatus including one or more first flowlines and lowered along said system into communication with the well bore with end portions of said one or more flowlines facing said alignment means, a guide assembly lowered along said system to a location adjacent to said flowline guide structure, a carrier, one or more second flowlines carried by said carrier and adapted to be lowered therewith through the body of water after said flowline guide structure has been moved to said predetermined position, connector means secured to said one or more second flowlines, and means interconnecting said guide assembly and carrier for pulling said carrier, connector means and one or more second flowlines toward said guide assembly and flowline guide structure to engage said connector means with said alignment means whereby said connector means is positionable in alignment with said end portions of said one or more first flowlines, and means for operatively connecting said one or more first flowlines and one or more second flowlines to each other, whereby fluid can flow therebetween.

9. In apparatus wherein a guidance structure is disposed at and extends upwardly from the floor of a body of water and through which a well bore has been drilled into the underlying formation, the guidance structure including upwardly extending guide posts and guide lines extending upwardly from the posts, the combination therewith of a flowline guide structure movable along one or more selected guide lines and over one or more guide posts connected thereto, flowline alignment means secured to said flowline guide structure, fluid flow apparatus including one or more first flowlines and lowered down the guide lines and over the guide posts into communication with the well bore with end portions of said one or more flowlines facing said alignment means, a guide assembly lowered along said one or more selected guide lines and over said one or more guide posts connected thereto, a carrier, one or more second flowlines carried by said carrier and adapted to be lowered therewith through the body of water after said flowline guide structure has been moved over said one or more guide posts, connector means secured to said one or more second flowlines, and means interconnecting said guide assembly and carrier for pulling said carrier, connector means and one or more second flowlines toward said guide assembly and flowline guide structure to engage said connector means with said alignment means whereby said connector means is positionable in alignment with said end portions of said one or more first flowlines, and means for operatively connecting said one or more first flowlines and one or more second flowlines to each other, whereby fluid can flow therebetween.

10. In apparatus as defined in claim 9; means releasably securing said guide assembly to said flowline guide structure, and means for releasing said securing means.

11. In apparatus as defined in claim 9; and means releasably securing said carrier to said one or more second flowlines.

12. In apparatus as defined in claim 9; means releasably securing said guide assembly to said flowline guide structure, means for releasing said securing means, and means releasably securing said carrier to said one or more second flowlines.

13. In apparatus as defined in claim 9; said guide assembly including one or more funnels, said carrier including one or more probes receivable in said one or more funnels to engage said connector means with said alignment means, said pulling means including one or more lines connected to said one or more probes and passing through said one or more funnels.

14. In apparatus as defined in claim 9; said guide assembly including one or more funnels, said carrier including one or more probes receivable in said one or more funnels to engage said connector means with said alignment means, said pulling means including one or more lines connected to said one or more probes and passing through said one or more funnels; means releasably securing said guide assembly to said flowline guide structure, and means for releasing said securing means.

15. In apparatus as defined in claim 9; said guide assembly including one or more funnels, said carrier including one or more probes receivable in said one or more funnels to engage said connector means with said alignment means, said pulling means including one or more lines connected to said one or more probes and passing through said one or more funnels; means releasably securing said guide assembly to said flowline guide structure, and means for releasing said securing means; and means releasably securing said carrier to said one or more second flowlines.