DE2116852A1 - Underwater ground anchors for floating drilling rigs and the like, and methods of laying them - Google Patents

Description

UNITED STATES.

Underwater ground anchors for floating drilling rigs and the like, as well as methods for its laying

The invention relates to a ground anchor for anchoring of off-shore drilling rigs, platforms and similar working platforms arranged above the water surface. This ground anchor is to be lowered to the seabed and a floating body connected to the drilling platform above the drilling rig hold in a vertical position.

When drilling for or conveying oil, gas and other petroleum products in the marine area (offshore) - it has been shown that under certain conditions floating platforms or drilling rigs are more suitable than fixed ones. This floating platforms or drilling rigs are usually verschon having an elongated floating body, which is attached at its lower KNDO to a :; "Fund Mont block or ground anchor of r..? \ Nov Arhn.i.trbv'hne ru the floating structure made can d ° nn after Ol or Gar, g ^ boh ^ t been.

Ihr'T grofien Abtn " ^r :. 'uri <-' nn und fiev ^ Lived represents the Vr-r-

;: · '> L.chr-r »CrVtmd'ini. · -R, inrluiiinsidero in deep' farspr,

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21TS852

poses a considerable problem. To serve probion at least a little to partially solve, you already have such anchors designated location and sunk there, '.fcnn the anchor is partially embedded in the seabed in this way has been, the platform or its rigid floating body is attached to the anchor with the lower end. The Connection between the float and the ground anchor must be so flexible that it can displace forces like Wi η el, Can absorb water emanations, many and the like. Farther the connection must also face unfavorable weather conditions can easily adapt to the sea surface.

k Another problem related to such anchorages, especially in deep water, results from the topographical unevenness typical of the seabed. In addition Not only does a generally uneven floor count, but irc essentially a gradual or steep drop in the bodon. For example, the continental shelf or the outer shelf drop so sharply in some sections that a normal anchor body cannot come into a horizontal position at all.

The subject of the invention is an underwater ground anchor for floating drilling rigs and the like, which have a submerged part which extends to the sea floor and is provided with connecting devices on the lower troughs, ψ characterized by

a coupling member having a vertically upward projecting connector which engages in the connecting means of the submerged part and laterally ⁰ movements thereof under the action of oiir-arkenden it inhibits forces, and

a multi-part anchor body, which is arranged on the seabed and nit the JO'pplv.n.fng " ¹ iocl so connected int, d-ii? er the perpendicular · TjP'o dos Verbi ^ du ^^ crtuc '" ¹ ^ r' ^ v ^ hrloint ⁰ "^, wobrvi the anchor body passage; 'Vein.

109843/0148

According to the invention, the base therefore consists of one Multiple parts, so it can go up to laying are decomposed on the seabed, but is there with cement solidified into a uniform structure.

The invention will be explained in more detail with reference to the drawing, in which:

Figure 1 is a side view of an offshore floating platform that is anchored to the seabed,

Figures 2 and 3 are partially sectioned (on a larger scale) sections of the ground anchor of Figure 1,

Figure 4 is the partially sectioned side view of the is shown in Fig. 2 and 3 coupling member and

Figures 5a to 5e are side views illustrating the laying of the ground anchor.

As FIG. 1 shows, a typical offshore drilling rig, in which the ground anchor according to the invention is used, consists of a floating platform 10 which is set up for drilling holes in the seabed. Its surface is shown in FIGS. 1 and 2 with an exaggerated inclination. The platform 10 contains a working platform 11 with a derrick 12, drilling winches and other necessary equipment for oil drilling or production work. The working platform is usually 15 to 18 m above the water surface in order to keep the work equipment out of the '.' Range in heavy seas.

The work platform 11 is? Ine Irnrgestreckte support structure rchr.lten 1J- consisting of one or more legs, ^ ie from the "eater surface to the sea floor rich, T) ± e Krltrkonrtruktien 13 is a B = IIpstsyst ^ ms by the incorporation ..? made floatable this in the figures do not ~ .r detail dnrgcstellte llastsyste B "i consists of clothes disposed in the Abrtand ngsriclt L from each other in ^{y-SCLV'ip.niTr.nks,} wherein in the a ^ elnori Tcirilis the buoyancy -" ** '? "" -ι " ¹ ifji * ·" ^ ι- · - «-" dcrr *. ^ td) ο Ι. ·? "Ό the H ^ li ^ kon

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In normal working conditions, regulation of the buoyancy of the anchor body 14 and adjustment of the buoyancy of the HcIte construction 13 the latter takes a generally perpendicular Position up to a desired barrel depth on the Offshore place of work. The bottom of the Holding structure 13 coupled to the recessed anchor body 14 and held by one or more flexible cables. The Schwinraplattforn can be calibrated with the working platform 11 and the holding structure 13 in the water to a certain degree, but remains εο stable, doß the work can be carried out on the work platform.

In the illustrated arrangement, the floating platform is 10 anchored in place. It goes without saying that the entire support structure 13 continues through the tides ^ water level fluctuations of several meters up to about 9m high, depending on where the drilling rig is located in the sea. So to get the swimming platform in the desired to stabilize the vertical position, the lower end of the support structure 13 must be attached to the anchor body 14, but not to be rigidly connected to it.

As FIG. 2 shows, the anchor body 14 arranged on the seabed contains a number of individual but cooperating arranged elements. These elements basically include a coupling member 16, which from one from one, each Ballastable lower part 18 and upper part 19 existing anchor body 14 is held. The latter house tanks that have flooded can be necessary to the anchor body 14 d ^ s To give weight, whereby it can either sink to the seabed or be kept floating.

Fig. 3 shows that the ground anchor, before it is assembled into a unitary whole, has a coupling member 16 which is formed at the upper end so that it engages the lower end of a floating platform and holds it slidingly. The coupling member 16 has drs ρine spherical or hemispherical shape, in a Hch '· 3 rrehalten Erlich T.um inside the armature 14 Korner bo ^?. After it is in its final

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valid position has been brought so that it is the swimming platform keeps as beneficial as possible, the cavity in the anchor body is filled with a hardenable material to protect the To fix the coupling member 16 and determine its perpendicular position and thus the swimming platform in the best possible position admit.

As shown in FIG. 4, the coupling member 16 has at one Embodiment a body 21 which is shaped outwardly is that it is held movably by the upper part 19. The body 21 is slidably held in the cavity 23 so that the connecting piece 22 can assume the desired vertical position. Preferably, the final arrangement is as follows: that the connector 22 is aligned substantially perpendicular. When that is achieved, the connector will 22 slide into a corresponding sleeve 25 in the lower end of the holding structure 13.

The body 21 of the coupling member 16 may have any of a number of geometric shapes and is spherical, hemispherical or the like in the present device. The function of the curved body 21 consists according to the invention therein, the coupling member 16 ichkeit before Einzcmenticrung a certain degree of movement to poss-all S i-th _SS to give out. Although the body in the figures has a generally spherical shape, it should be understood that it is intended to have a geometric shape that allows sliding between the outer surfaces of the. Body and the adjacent., Walls of the cavity 23 surrounding the body. It is known that this possibility of movement can also be achieved by contacting non-spherical, but similarly shaped, friction surfaces.

The connecting piece 22, which nr-.ch from the surface the Küvpnrr, 21 r-mporrrgt, int firmly inserted into the latter. ■ Rine M-mr-chctte ? Jv ηη the lower end of the connecting piece 22 forms an intermediate ring between the lower end of the Ver-T) Indunr'j '.- rtnckos 2 ° and the ob · ""; · surface of the body 21 The connecting piece 22 is a generally long, long, cylindrical

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drical element of uniform diameter that is large is enough to put the piece into the sleeve 25 of the Holtckonotruktion 13 to click into place.

Before twisting on the seabed, the body 21 is held from above in sliding contact with the bindings of the cavity 23, and by the pull exerted on the guide cable 45 and the connecting piece 22 from above, the lower part 18 is indifferent to the seabed -.-. ^r what topographical shape he may lift, be straightened out.

In order to have a better contact between the coupling element 16 ur.d | to produce the cavity 23 in the anchor body 14 is the The outer surface of the body 21 is provided with a number of recesses 26. However, these can also take the form of spaced apart arranged elevations on the outer surface, whereby the cement is offered a larger adhesive surface.

The body 21 can be made of rolled steel sheet and is shaped and welded together so that its surface is slidably received by the corresponding seat of the cavity 23.

The interior of the body 21 is separated by dividing plates or webs 27 and 23 arranged at right angles to one another Chambers 29 and 29a. These webs are so arranged arranges that thereby the walls of the body 21 are stiffened or reinforced. The respective chambers can continue to do so Have valves through which the chambers for lowering the coupling member 16 are flooded.

The upper part 19 is generally designed like a controllable floating body with buoyancy chambers that are connected to a buoyancy system. The upper part 1 ° is proportioned in such a way that it holds the coupling element 16 on the water surface without ballast or without water, thereby facilitating its transport on the water surface and facilitating the installation.

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ÖÄD OBiOiMAL

The top 1? Contains ^ i ii cavity segment 31, deP,?. on surface e'er For "! d ^ s correspondingly, en upper toilet ο corresponds to the KuO- ^ lunpsgliedkörOcrr 21. The hollow r ^ uncerrnent 31 opens at the top of the upper part 19 in. a before or. "th opening 33. Dr.ρ Hohlrounr.egmcnt 3 ^Λ is preferably formed by an inwardly curved and beveled wall, which in the narrowed opening 3? expires. The diameter of the narrowed opening 35 is large enough that the connecting piece 22 can move freely while the body 21 is slidably aligned in the cavity 23.

The underside of this upper part 19 is also proceed with two or more Pp.ßlöehern 33 A'cr ^ which the corresponding Paßrtiite ~ 5k pufnehmon that s are rur.gebildet 18 on top of the Untertei?,.. So can the bottom of the upper part 19 and the top of the lower part? 18 easily join together via remote control pn seabed. From the fitting holes 33 in the upper part. 19 guide guides 36 lead upwards, and a flexible cable 37, the lower end of which at the end of the connecting pieces? 22 is attached, is passed through the guide holes 36. With the aid of this cable, the upper part 19 and the lower part 18 are slidably joined together after the lower part 18 has been lowered onto the sea bed at a drilling location.

The lower part 18 has a top surface that is not just the Body 21 and the coupling member 16 captured to it in the cavity 23 -U hold, also round the underside of the upper part 19, in order to form a single part. That Lower part 18 has approximately the shape of a steel pontoon with evacuable buoyancy chambers 42, which are connected to a buoyancy regulator, so that the lowering of the lower part 18 carried out in a controlled manner.

The coupling member 16 is cemented in the anchor body cavity 23 via one or more cement passages 39 which lead through the upper part 19 and the lower part 18 to the hollow space 23. These passages open at the top of the upper part 1 ^Q and can be connected to flexible lines 43 on ^ e-

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be closed, which in turn reach up to the surface of the water, from where they carry liquid 'cement down into the ground anchor -.

As shown in FIGS. 5a to 5e inclusive, an anchoring according to the invention is carried out normally for the arrangement of a swimming platform 10 shown in FIG. 1, the holding structure 13 is one or more elongated ones Legs which are arranged at the lower end so that they are at least one of the body 21 of the coupling member 16 towering connector 22 can slide. The anchor body 14 including the coupling member 16 and the upper part 19 are towed to a designated location, where they are then submerged. Both the top as well as the lower part 18, which together hold the coupling member, are held on the water surface by Drains water from the buoyancy tanks in the individual anchor parts. ·

At the intended place of work, the lower part 18 is released from the upper part 19 and by evacuating the. Buoyancy tank 42 lowered. The guide cable 45 is connected to the connecting piece 22 protruding from the anchor body 14 and through the Guide hole 36 guided upwards onto the platform. That The lower part 18 with the supports 51 and 52 is at least partially fixed by its own weight on the seabed on whose surface design it depends, how much its location corresponds to the subsoil and the general Slope of the floor deviates from the horizontal.

Next, the coupling member 16 is separated from the upper part 19 and steerably supported by the central guide cable 45.

To reduce its buoyancy, the coupling element is first flooded and then lowered in a controlled manner, until it enters the open cavity 38 of the lower part 18 is embedded.

109843/0148

If the guide cable "45 is affected by noticeable forces such as e.g. affects a heavy countercurrent or countercurrent in the water it will bend and thereby the connecting piece deflect in the direction of flow. In such circumstances, the coupling member 16 can have two sides protruding, detachable arms that hold the cables

37 slide, which prevents the Coupling member 16 is inhibited when it is lowered.

After the lower part 18 and the coupling member 16 are placed on the seabed, the buoyancy of the upper part 19 is reduced and after diminished. The upper ends of the cables 45 are held above the water surface and run on the Top of the swimming platform 10 to a winch. On the sea floor, the upper part 19 is secured by the dowel pins 34 and the fitting holes 33 aligned with the connector 22 previously positioned. If the top is right sits, it forms a conclusion over the cavity segment

38 and thus a substantially spherical or hemispherical one Socket for the body 21.

By pulling the cable 45 upwards, the connector 22 is aligned vertically. Once that is achieved, it becomes more fluid Cement through line 43 and passage 39 into the hollow space 23 initiated. When the cavity between the body 21 and the cavity walls fills with cement, cement will through the opening 35 overflow. As a result of the subsequent hardening of the cement, the connecting piece 22 thus becomes more perpendicular Fixed position, so that the holding structure 13 can then be erected in addition on it.

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Claims (8)

- ίο - T 71 014 (D 71,652-5-F) Claims (1) Juhterwasser ground anchor for floating drilling rigs and The like, which are provided with connecting devices at the lower end, which extends to the sea floor have submerged part, characterized by a coupling gliod (16), which has a vertically towering Having connecting piece (22) which engages in the connecting device (10,13,25) of the submerged part and inhibits lateral movements of the same under the action of forces acting on it, and a multi-part anchor body (14) on the seabed arranged and connected to the coupling member (16) so that it the vertical position of the connecting piece (22) ensured, wherein the anchor body (14) passages (39) for the pressing of a hardenable liquid in the anchor body (14) for the fixed connection of the anchor body (14) and the coupling member (16) open. 2) underwater ground anchor according to claim 1, characterized by Means (31,38) for creating a cavity (23) in the anchor body (14), a body (21) which slidably fits into this cavity (23) and forms part of the coupling member (16), the the alignment of the connecting piece (22) in the vertical position allows, and a connection of the cavity (23) creating means (31 "38) with the passages (39) to the hardening Introduce liquid into the cavity (23). 109843/0148 2Π6852 3) underwater ground anchor according to claim '?., Thereby characterized in that the anchor body (14) has a narrowed opening (35) on the upper cover surface through which the connecting piece (22) passes, when the body (21) is let into the cavity (23). 4) underwater ground anchor according to claim 3, characterized characterized in that the breakthrough (35) allows limited movement of the connector (22) therein for the connector to become perpendicular leaves when the anchor body (1 ^) is not horizontal rests on the seabed. 5) underwater ground anchor according to one of claims 1 - 4, characterized by buoyancy chambers (30, 42) in the anchor body (14) to change its buoyancy. 6) underwater ground anchor according to one of claims 1-5 »characterized in that the Anchor body (14) consists of an upper part (19) and a lower part (18) and the upper part of which the cavity (23) creating means (31), which adjoins the opening (35), is penetrated and which the cavity (23) creating means (3B) is arranged in the lower part (18). 7) underwater ground anchor according to claim 6, characterized in that the upper part (19) Has guide holes (36) for the passage of guide cables (45) which are attached to dowel pins embedded in the lower part (18) (34) are attached. 109843/0148 2116052 8) A method for laying the underwater ground anchor according to claims 1-7 on the seabed, dad urch in that brings the anchor body and at the Y ^r asseroberflache about the proposed location separates its lower part from the rest of the anchor body and lets it down to the seabed using the guide cables, the articulated coupling member on a guide cable is lowered into the cavity of the lower part, lower the upper part on the guide cables onto the lower part and over the coupling link, aligns the connector vertically and presses a hardenable material into the cavities of the anchor body, in order to consolidate its previously movable individual parts into a unified whole. 109843/0148 -Λ. Blank page