FR2533954A1 - APPARATUS AND METHOD FOR FIXING A JIG IN AN UNDERWATER PRODUCTION PLACE - Google Patents

Abstract

THE INVENTION RELATES TO AN APPARATUS AND A PROCESS FOR FIXING A TEMPLATE IN AN UNDERWATER PRODUCTION SITE. THE EQUIPMENT INCLUDES A CARDAN MECHANISM 42 MOUNTED WITH ROTATION ON THE TEMPLATE 40 AS WELL AS A LOCKING DEVICE 46 MOUNTED WITH ROTATION ON THE CARDAN MECHANISM 42 FOR FIXING THE TEMPLATE ON THE SINGLE BEARING PILLAR. APPLICATION TO OFFSHORE OIL OPERATIONS.

Description

APPARATUS AND METHOD FOR FIXING A JIG IN A PLACE

OF UNDERWATER PRODUCTION

  The present invention relates to a sub-production unit

  which connects several hydrocarbon production wells, to pipelines for the transport of hydrocarbons to storage facilities, and more particularly to a process and

  apparatus for fixing a template in a sub-production area

  Marine. For the current oil production, the exploitation is carried out

  in areas of high seas where the water depth can reach 762 m.

  Underwater production is more economical if several wells are drilled

  in the same area with different slopes so as to obtain a

  More efficient wells A collecting and distributing structure is then used to collect the outgoing flows of the different wells in one or two pipes for the transport of liquid or gaseous hydrocarbons up to

  storage facilities or to a ship which then trans-

  port to refineries Generally the collector and distribu-

  trice is supported on a template that is placed on several pillars, which is put

  level by adjusting the heights of the respective pillars and which is fixed-

  lidonsurchacundes pillars The collector and distributivetructure also includes several arrays, the majority of which are used as links with wellheads One or two of the arrays are used for links

  with pipeline bundles carrying the free hydrocarbons

  or gaseous to a distant destination.

  The concrete pillars on which the template is placed are usually

  The pillars are dark in the ocean floor with the help of a submarine anchor. Once the concrete pillars are in place, they must be adjusted to a minimum of 10 meters in length. the template, which is generally 16.6 m in diameter, is level at less than 7.6 cm transversely

2 2533954

  its diameter In order to appreciate the importance of this problem, it should be noted that, for a 7.6 m diameter template, a slope of 50 with respect to the horizontal results in a difference greater than 0.6 m between one side

of the template and the opposite side.

  When the depth increases to 762 m, leveling becomes more and more difficult, especially with the principle

multi-pillar support.

  Consequently, the invention relates, in a variant, to an apparatus for fixing a template in an underwater production site at

  means of a single supporting pillar comprising a cardan means mounted to rotate

  on the jig and a locking means rotatably mounted on the jig

  medium to cardan, so as to fix the template on the pillar.

  In another aspect, the invention relates to a method for attaching a jig to an offshore production site, comprising the steps of driving a single bearing pillar into the ocean floor and locking the jig on the mainstay that this pillar

  is the only support for the template.

  Other features and advantages of the invention will be Ois

  prominently in the following description given by way of example no

  limiting with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a single pillar support; Figure 2 is a plan view of a leveling plate; Figure 3 is a side view withdrawal of Figure 2; Figure 4 is a plan view of a jig and gimbal-mounted locking system; Figure 5 is a side view taken along lines IV-IV of Figure 4; Figure 6 is a plan view of a slip segment locking system;

  FIG. 7 is a partially cutaway side view of FIG.

  Referring now to FIG. 1, it will be seen that there is shown a single pillar carrying assembly 12 on which an annular beam 14 is fixed. A single pillar is superimposed in phantom lines.

  12A and an annular beam 14A highlighting variations of

  The single pillar 12 may be formed of any commonly used bearing material. However, in the preferred embodiment, a steel tube having a outer diameter of 1, 8 m and a thickness of 5.1 cm This single bearing pillar 12 may have a length of 91 m, only a few tens of centimeters exceed

  from the surface of the mud from the bottom of the ocean.

  As shown in Figure 1, a difference of 50 from the vertical

  wedge at the top of the single pillar 12, results in a gap greater than 0.6 m between a corner 16 and the opposite corner 18 of the annular beam 14 The annular beam 14 can also be of a type commonly used to initially support the weight of the jig that leans on it The beam

  ring 14 may be attached to the single pillar 12 by conventional methods.

as by welding.

  The single pillar 12 and its annular beam 14 can be installed in a water depth of 762 m by driving them with the aid of a submarine grinder. The tolerance regarding the verticality of the axis of the pillar can be between 0 and 5 in all directions A template with ten bays is preferably placed on the pillar and is leveled to less than half a degree from the horizontal to allow

  subsequent operations A more detailed description of a sub-template

  marine can be found in the published UK patent application

No. 2 114 188.

  Normally, the single pillar 12 extends approximately 3 m above the ocean floor and has an annular beam assembly 14 with a diameter of 16.6 m which is attached to the mud surface. slope of 50 causes a deviation of more than 0.6 m transversely to the base of 7.6 m of the beam, so that the jig

  when descended, must be leveled to plus or minus 6.65 cm trans-

  Versely at the same diameter of 7.6 m A steeply sloped surface poses problems of drilling, pumping and connection which, because of the depth at which the platform is used, require many

  hours of work and big fees to be solved properly.

  An approximately level gauge surface is an important

  prerequisite for the safe and efficient operation of a system

  underwater production system which contains connection parts

  with oil well heads and production lines.

  Looking now at Figures 2 and 3, we see that we have

  a leveling leveling board 20 which includes a slot for

  22, a handling eyelet 24,

  26 and lifting pins 38 The plate 20 is a structural component

  prefabricated rel that is built before the phase-installation but is designed to be adjustable on site The tray is centered on the pillar

  only with the toy is an upper level surface

  that its lower surface is set in place to compensate for the angle of the plate 14 of the annular beam The plate does not need to be precisely centered, but it requires orientation relative to the single pillar 12 This can be achieved with an orientation pin 30 (FIG. 3) on the plate 20 A precise orientation is not critical, since an orientation error of 1800 produces a leveling error which is only 10 As a result, an orientation error of

  a few degrees translates into a small leveling error.

  An underwater platform therefore does not require any

  leveling, because the foundation was upgraded.

  A large support surface is also obtained. A separate orientation of an underwater platform is possible if it is carried out before

  the weight of the template is not transmitted to the plate 20

  20 is placed on the annular beam 14 and is found incor-

  rect, it can be pulled backwards towards the surface more

  and faster than a large underwater platform base.

  In operation, the distance from the single pillar 12 (FIG. 1) is measured

  and the slope of the annular beam 14 is calculated.

  manufactured to compensate for the determined slope of the annular beam 14 The tray 20 can be lifted by the lifting pins 28 and it can be

  down on the annular beam 14 and on the single pillar 12 by means of

  ceded commonly used in underwater construction The plateau 20

  has a central mouth 32 which defines a funnel from bottom to top.

  The top of the central mouth 32 has a diameter of about 1.8 m while the bottom has a diameter of about 3 m This allows to lower the plate 20 on the single pillar 12 while a misalignment of the central aperture 32

  compared to the center of the single pillar 12 can reach a value of 1, 2 m.

  The funnel-shaped arrangement of the mouth 32 provides centering on the single pillar 12 and allows alignment with side walls of the mouth.

annular beam 14.

  The plate 20 is arranged to compensate for a gap of the single pillar 12 with respect to the vertical, which causes the base of the annular beam 14 to tilt relative to the horizontal As shown in FIG. 3, the plate 20 ' may consist of two superimposed concentric segments 20A, 20B, rotatable relative to each other; each

  segment is in the form of a circular wedge, defining

  a corner angle of 2.5 between its upper and lower surfaces so that, by varying the annular orientation of the segments, the angle between the upper and lower surfaces of the entire tray can be adjusted between O Q and 5 Each segment consists of sheets

  of steel and circular and radial stiffeners 39 are provided for

  to the plateau sufficient resistance for the transmission of efforts

  compression occurring in service.

  Before the plate 20 is lowered into place on the plain pillar (aI 12 and the annular beam 14, the angular orientation of the segments 20 A, 20 b,

  is adjusted to compensate for the slope in the annular beam 14.

  After the tray has been installed, the accuracy of this setting can be

  confirmed by visual inspection of slope indicators 26.

  The use of the single pillar 12 as sole support of the template, poses a problem sup Element on the locking of the template on the single pillar 12 Consequently, the template must be securely fixed

  on the single pillar 12, even when it departs from the vertical.

  However, the plate 20 allows the template to take a level position, so that the central axis of the template 40 is always substantially vertical, but it is inclined at an angle with respect to the central axis

  of the single pillar 12 when it deviates from the vertical-.

  Referring now to FIGS. 4 to 7, it can be seen that the template is shown as being connected to a gimbaled ring 42 via a universal joint 44 and having a sliding lock 46

  hydraulically actuated and secured to the ring-42 by a universal joint 48.

  The hydraulically actuated sliding lock 46 is mounted around the single pillar 12 and can rotate to compensate for a distance of the pillar 12 from the vertical. However, a compensation of a deviation from the

  vertically using the hydraulically actuated slide lock 46 may only

  offset compensations included in the arc of 900 of the universal joint 48, that is to say deviations of + 450 relative to the central axis 50 of the joint

universal 48.

  The universal joint 44 connecting the gimballed ring 42 and the jig 40 is spaced 90 from the central axis 50 of the universal joint 48, having a central axis -52 perpendicular to the axis 50. The universal joint 44 compensates the differences of the single pillar 12 with respect to the verti (-lr, -I Ji are + 450 relative to the central axis 52 Consequently the template 40 can be lowered on the plate 20 and locked on the single pillar 12 in Despite its deviation from the vertical Figure 5 shows the universal connection 14 with the ring 42 mounted to the universal joint and the universal connection 48 with the slide lock 46 hydraulically actuated As shown, the template 40 can be put in place on the tray 20 while the hydraulically operated lock 46 slides down the single pillar

  The template 40 is supported on the tray 20, while the lock 46 is

  hydraulically is arranged to extend to a level

  located slightly above the plateau 20.

  As indicated in FIGS. 6 and 7, the hydraulically actuated slide lock 46 comprises sliding segments 50, 50 A in which

  52, 52 A The sliding lock 46 also includes

  hydraulic lugs 56 connected to the corners 52 and 52 A respectively in juxtaposition

  position with the sliding segments 50 and 50 A The sliding segments 50 and the corner 52 show the elements in an unlocked position, while the sliding segment 50 A and the corner 52 A show the elements in position

locked -

  The hydraulically actuated slide lock 46 must be remotely operable and able to provide effective locking on the single pillar 12 despite forces exerted on the jig 40 or the pillar 12. This means that the hydraulically actuated slide lock 46 must not be likely to relax when operational forces

  The combination of the corners 52 and sliding segments

  establish a solid connection necessary.

  In operation, the hydraulically actuated slide lock 46 is lowered onto the single pillar 12, with the corners and sliding segments in their unlocked position. When the lock is in place, the hydraulic cylinders 56 are actuated to push the arm

  piston 58 against the corner 52 A by causing it to slide the sliding segment

  Against the pillar 12 Once in position, radial or transverse forces exerted on the jig 20 or on the single pillar 12 are

  transformed into radial forces by making the inclination angle

  Because of the angle of the wedge 52 with respect to the sliding segment 50 being small, radial forces are almost perpendicular to the surfaces 60 and 60A of the corners 52 and 52. Thus, the corners 52 and 52 A maintain their position by forcing the sliding segments 50 and 50A. to stay closely enforced against

the single pillar 12.

  The slide lock 46 hydraulically actuated makes contact

  effective with the pillar 12 and acts, via the universal link

  verselle 48, of the gimbal ring 42 and the universal link 44,

  to ensure a solid mounting of the template 40 on the single pillar 12.

Claims (5)

  1. Apparatus for fixing a jig (40) in a place   submarine production using a single supporting pillar (12),   characterized in that it comprises a universal joint (42) rotatably mounted on the jig (40) and a locking means (46) rotatably mounted on the gimbal means (42) for fixing the jig (40) to the pillar carrier (12).   2. Apparatus according to claim 1, characterized in that the   locking means comprises means (50, 50 A) for   carrier-bearing wedge means (52, 52 A) slidably mounted   in contact with the attachment means to push the means of   against the supporting pillar (12) and an actuating member (56) ac-   hydraulically and connected to the wedge means for moving the latter into a pushing position of the hooking means against the bearing pillar (12).   3. Method for fixing a jig in a sub-production site   marine, characterized in that it comprises the steps of darkening a single bearing pillar (12) in the ocean floor and locking the jig (40) on the pillar so that this pillar (12) forms the only one template support.   The method of claim 3, characterized in that the locking step comprises the steps of placing a cardan-mounted latch (42, 46) in the assembly at the center of the template (40),   turn the latch (42, 46) to compensate for a vertical   unit (12) and removably fix the template (40) to the   bonding a single carrier (12) to the lock (42, 46).   The method of claim 4, characterized in that the detachable securing step comprises the steps of providing slip segments (50, 50 A) which are slidably mounted in association with wedge members (52). , 52 A) actuated by hydraulic members (56) and actuating the hydraulic members (56) to push the elements   forming wedges against the sliding segments-and thereby pushing the segments   slippery elements (50, 50 A) to form the single carrier pillar (12).