U.S. patent number 3,700,048 [Application Number 04/889,357] was granted by the patent office on 1972-10-24 for drilling installation for extracting products from underwater sea beds.
Invention is credited to Robert Desmoulins.
United States Patent |
3,700,048 |
Desmoulins |
October 24, 1972 |
DRILLING INSTALLATION FOR EXTRACTING PRODUCTS FROM UNDERWATER SEA
BEDS
Abstract
An installation for extracting products from underwater sea beds
comprises a base section which is permanently sunk in the sea bed,
a reusable well section, and water-tight flexible connecting means
releasably connecting together the base section and well section.
The well section has sufficient internal dimensions to allow
workmen and equipment to pass therethrough and is open to the
atmosphere so that the working space for the workmen is maintained
at atmospheric pressure. The reusable well section may be
disconnected from the base section and reused again at another
extracting site.
Inventors: |
Desmoulins; Robert (59
Valenciennes, FR) |
Family
ID: |
9693882 |
Appl.
No.: |
04/889,357 |
Filed: |
December 30, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Dec 31, 1968 [FR] |
|
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6819266 |
|
Current U.S.
Class: |
175/6;
175/171 |
Current CPC
Class: |
B63B
35/4413 (20130101); E21B 41/06 (20130101); E21B
7/12 (20130101); E21B 7/124 (20130101); E21B
3/045 (20130101); E02B 17/027 (20130101); E21B
17/01 (20130101); E21B 7/20 (20130101) |
Current International
Class: |
E02B
17/00 (20060101); E02B 17/02 (20060101); E21B
3/00 (20060101); E21B 3/04 (20060101); E21B
41/06 (20060101); E21B 7/12 (20060101); E21B
7/20 (20060101); E21B 17/01 (20060101); E21B
7/124 (20060101); B63B 35/44 (20060101); E21B
41/00 (20060101); E21B 17/00 (20060101); E21c
019/00 () |
Field of
Search: |
;175/6,8,9,7
;166/.5,.6 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Novosad; Stephen J.
Assistant Examiner: Favreau; Richard E.
Claims
What is claimed is:
1. Installation for laying an underwater, recoverable base for
extracting by means of drilling means oil, gas or any other useful
products available under the sea bed, by anchoring supporting
masts, floating or fixed islands, or other surface offshore
installations, which comprise: a recoverable well having means
opening into the free atmosphere and having transverse dimensions
sufficient to enable a gang of workmen to have access to the bottom
of said well; drilling means for performing a drilling operation
installed in the bottom of said well; a well base pivot permanently
sinkable in the sea bottom bed; means for rotatably driving said
base pivot about its longitudinal axis in order to sink same into
the sea bed; and water-tight flexible connecting means disposed
between said base pivot and said well to allow a slight inclination
or oscillation of said well in relation to said base pivot.
2. Installation as set forth in claim 1, wherein said water-tight
flexible connecting means disposed between said base pivot and said
well comprises a flexible membrane, a set of flanges one carried by
said well and the other by said base pivot for gripping the edges
of said membrane, and a presser cylinder and piston units
positioned to exert a pressure on the membrane portion lying inside
said well and to react against a fixed point on said base pivot to
balance the external pressure.
3. Installation as set forth in claim 1, wherein said means for
rotatably driving said base pivot comprises propeller power units
having horizontal axes and disposed externally and at spaced
intervals about the periphery of said well.
4. Installation as set forth in claim 1, wherein said well
comprises at its lower end a working chamber at atmospheric
pressure and a double-walled body constituting a fluid-tight
annular jacket receptive of a ballast material for compensating the
Archimedean thrust.
5. Installation as set forth in claim 1, wherein said base pivot
comprises a cylindrical body having a relatively thick wall, means
defining channels extending longitudinally in said wall opening at
one end into said body and at the other end to the outside of said
body to permit the injection of concrete, a retaining bell for
preventing the injected concrete from rising, a first drilling tube
housed within said base pivot, a drilling rod and head unit housed
in said first drilling tube, and at least one tube for injecting
water under pressure and evacuating the drilling products disposed
in the annular space bound and defined by the cylindrical body of
said base pivot and said internal drilling tube.
6. Installation as set forth in claim 1, including at least a lower
pivot pipe and an upper well pipe, and mechanical means assembling
said pipes in an end to end relationship while allowing a slight
oscillation of one pipe in relation to the other.
7. Installation as set forth in claim 6, wherein said mechanical
means comprises a compressible bellows.
8. Installation as set forth in claim 6, wherein said mechanical
means comprises a ball-joint, and sealing elements fitted in said
ball-joint.
9. A partly reusable installation for extracting products from a
sea bed comprising: a reusable well section having an elongated,
hollow configuration and having sufficient interior transverse
dimensions to enable workmen to pass through said well section from
one end to the other end and positionable in a vertical disposition
in the sea to communicate said one end with the atmosphere whereby
the interior of said well section is at atmospheric pressure during
use of the installation; a well base section having anchoring means
responsive to rotation thereof for permanently anchoring said well
base section in the sea bed; water-tight flexible connecting means
releasably and flexibly connecting together said reusable well
section and said well base section to enable relative movement
therebetween; extracting apparatus disposed within said reusable
well section at said other end thereof and extendable through said
well base section into the sea bed to extract products from the sea
bed; and drive means for rotationally driving said anchoring means
to effect permanent anchorage of said well base section in the sea
bed.
10. An installation according to claim 9; wherein said water-tight
flexible connecting means includes means connecting said reusable
well section and said well base section together for rotation as an
integral unit; and wherein said drive means comprises a plurality
of propellers connected in circumferentially spaced-apart
relationship around the exterior of said reusable well section for
effecting rotation thereof.
Description
The invention relates to an installation for laying underwater
bases leading to the open air intended for the extraction of
hydrocarbons or any other solid, liquid or gaseous mineral products
contained in the underwater bed itself, or taken from the surface
of it. This same apparatus can be used for anchoring points for
support pylons, fixed or floating islands and all surface maritime
installations.
For this type of installation, it has heretofore been necessary to
find available personnel with long training in diving techniques
and who were willing to work very arduous conditions.
The present invention relates to an apparatus for installing such
an installation and which obviates the forementioned drawbacks.
The present invention is characterized in that the drilling
operation for a shaft opening to the air, the base center-point
sleeve of which is implanted in the sea bed is carried out by
rotation of the center-point itself.
The present invention will be better understood with the aid of the
following description, made by way of nonlimiting examples, and
with reference to the accompanying drawings, wherein:
FIG. 1 is a vertical diagrammatic axial section of the well
drill;
FIG. 1a is a detail view showing, in axial section, a modified form
of embodiment of the seal provided between the pivot pipe and the
well pipe;
FIG. 1b is an axial section showing another modified form of
embodiment of the seal between the pivot pipe and the well
pipe;
FIG. 2 is a fragmentary axial section showing the lower portion of
the pivot pipe;
FIG. 3 is an axial sectional view showing on a larger scale the
pivot of the well drill;
FIG. 4 is a fragmentary vertical section of the well pipe;
FIG. 5 is an axial section showing on a larger scale the pivot and
the lower portion of the well pipe;
FIG. 6 is an axial section showing the equipment for installing the
first drilling tube;
FIG. 7 is a fragmentary axial section showing on a larger scale a
modified form of embodiment of the lower portion of the pivot
pipe;
FIG. 8 is a fragmentary axial section showing another form of
embodiment of the lower portion of the pivot pipe;
FIG. 9 is a diagrammatic sectional view of an anchoring layer;
FIG. 10 is a plan view from above of a workshop ship;
FIG. 11 is a diagrammatic side elevational view from astern of the
workshop ship;
FIG. 12 is a fragmentary plan view from above showing the workshop
ship on a larger scale;
FIG. 13 is a plan view from above of a pontoon workshop in its open
position;
FIG. 13a is a diagrammatic vertical section of the central portion
of the pontoon of FIG. 13, and
FIG. 14 is a plan view from above of a ship for laying the
anchoring means.
These internal arrangements are carried out on land before the
material is embarked on the floating workshop and transport to the
site where the drilling is to be carried out.
If the rig does not have a prohibitive length it is possible to
completely assemble same on the loading wharf and then tow if over
the water to the implantation site.
To put the rig into the vertical position, balancing ballast tanks
may be used.
Each sleeve section of the shaft-rig thus has a definite place in
the assembly.
In its entirety, the shaft-rig, shown in the present FIG. 1, is
essentially composed of three principal parts, a center-point
sleeve 1 implanted in the underwater bed, a shaft sleeve 2 which
leads to the open air and one or several hoops 3 which form the
articulated joints and serve as connections between the center
point sleeve 1 and the shaft sleeve 2.
The center-point sleeve is intended to be solidly implanted in the
underwater bed.
This implantation must bring about and guarantee that the base of
the entire shaft-rig is waterproof.
As a result, a rigid implantation; similar to that of a solidly
driven pile, should be made deep into the underwater bed.
The fact of being thus rigidly implanted then imposes the
obligation of guaranteeing the installation against all possible
oscillations about the vertical axis which could be provoked by a
shock which might affect the waterproofing of the sleeve 4 and of
the first boring tube 5.
Although underwater beds are generally considered to be calm
regions, for the sake of this invention, however, they are
considered as always being susceptible to perturbations by liquid
masses in various directions.
In order to eliminate all possibility of incidents due to forces
provoked by these large volumes of liquid in motion, the head of
the sleeve 4 which rigidly extends from the ground, is provided
with a flexible unit 6, which allows slight oscillations of the
center-point sleeve about the vertical axis of the shafts.
In certain particular doubtful cases of violent liquid movements,
these oscillations can be corrected and reduced to a minimum by the
addition of adjustable stays 7 which may be adjusted from inside
the shafts. In addition, it should be clarified that according to
the geological composition of the underwater terrain and relief at
the implantation site, the shaft-rig and, particularly, the
center-point sleeve 1 may be of a different conception thereby
allowing the judicious adaptation to the site under
consideration.
The center-point sleeve 1 essentially consists of a cylindrical
body with a double wall forming a waterproof space where the water
ballast 8 is provided and which allows all balancing operations for
traction or compression necessary to the implantation or to the
exploitation of the shafts.
This cylindrical body ends at the lower part by a spherical or
conical chamber 9, containing, in part, all materials and special
gear intended for the work of implanting of this center-point
sleeve 1 and the placing of the first tube 5 to carry out the
boring.
In order to allow for the installation of all the necessary
materials for the implantation of the shaft-rig and of the boring
itself, at the same time, the outside diameter of the center-point
sleeve 1 can be made to considerable dimensions.
Also, the upper part of this principal body ends in a cone which
allows the diameter of the center-point sleeve 1 to be made to fit
that of the shaft-sleeve 2, and the cone also allows the
center-point sleeve to be connected to the shaft-sleeves by means
of the intermediate flexible hoop 3. According to the depths to be
reached, this hoop can be of different design.
For slight depths, this hoop will be of the classic type and
produced in reinforced rubber or in all other flexible materials
which have acceptable mechanical and chemical characteristics
capable of resisting the forces posed on it by the environment.
For medium depths, it is proposed to utilize a compressible bellows
10 (FIG. 1a) in metal or in any other flexible material having
acceptable mechanical and chemical characteristics and capable of
resisting all forces imposed on it by the environment.
In an other variation of the embodiment, air cushions are also
placed in the undulations from the outside.
For great depths, a very strong ball and socket joint, (FIG. 1b),
capable of supporting the enormous vertical forces, is used the
waterproofing is insured by an assembly of inside joints 11. The
force applied on the outside joint by the pressure of the water is
balanced by a counter pressure applied to the inside surface. In
the case of failure of an inside joint, the resulting flow is such
that it can be held in spite of all the necessary pressure on the
outside point, even being able to be systematically created and
recuperated to be put back into the circuit.
The sleeve 4 (FIG. 3) of the shaft-rig consists of a steel sleeve
12 of considerable thickness.
The sleeve 4 is intended for boring the hole in the implantation
site and, at the same time, to hold the entire installation in
place.
This sleeve is connected to the body of the shaft-rig, by means of
the complex deformable assembly 6 (FIG. 2 and 5) forming a supple
joint which protects the fixed sleeve against all possibility of
shock caused by shaft oscillations. This articulation 6 (FIG. 2) is
constituted by a membrane 13 in rubber or any other flexible
material, even metal, gripped between two sets of flanges and
counter flanges, 14 and 15 as well as 16 and 17, forming a
waterproof fitting.
The very great force, resulting from the outside water pressure,
which is exerted on this supple membrane 13 is balanced by a series
of hydraulic jacks 18 connected to one or several oleopneumatic
accumulators. Each jack 18 controls the movement of a section 19.
The total all of these sections 19 uniformly is distributed on the
membrane 13 thus making a stop bearing of multiple layers capable
at all time to resist any collapse of the membrane 13.
In one variation of the embodiment, this articulation is obtained
by a unit consisting of flexible joints 20 held in equilibrium by
jacks 21 also connected to an oleopneumatic compensator (FIG.
8).
During all rotational movement of the entire shaft-rig, intended
for implantation, it must necessarily be maintained rigid in order
to eliminate all possibility of relative movement between the
sleeve and the entire body of the rig.
On the other hand, the membrane 13 must not be subjected to torsion
forces in the perpendicular plane of its axis and to prevent such
forces, blocking parts 22 (FIG. 2) have been provided.
In an other variation of the embodiment, the joint 6 is obtained by
a swivel similar to that described for the joint between the shaft
sleeve and the center-point sleeve.
The sleeve 4 (FIG. 3) is very thick because of the enormous forces
to which it is to be subject, and especially because this wall is
drilled longitudinally with the channels 23 opening to the outside
and intended for the injection of liquid concrete required to
achieve the absolute and sought waterproof condition.
This sleeve carries an external skirt at its upper part forming a
crown 24 which serves as a base its bell shape allowing the
injected concrete to be held in position.
The sleeve ends at its lower part by a particular unit which forms
the crown drilling tool holder 25 needed for its implantation.
In the inside of the center-point sleeve 4 is placed the first
drilling tube 5, the lower end of which preceded by the drilling
head 26 carried on the drilling shank 27, follows the progression
of the center-point sleeve 4 in driving.
In the annular space between the wall 12 of the center-point sleeve
and the drilling tube 5, are installed the conduit 28 for the
injection of water under pressure and the conduit 29 for the
extraction of drilling products.
The shaft-rig also comprises an implantation tool unit on the first
drilling tube 5 (FIG. 6).
This tool has three functions which are: the blocking of the end of
the center-point sleeve 4, the implantation of the first drilling
tube 5, and the recuperation of the shaft-rig when the sleeve 4 and
the first drilling tube 5 are implanted and the drilling work
finished.
This tool comprises three cylindrical bodies 31, 32 and 33.
The first body 31 is arranged to allow the evacuation of drilling
sludge produced by the sleeve 4 and the drilling head 26, at the
same time.
The body is fixed by flanges and bolts on the same base as the
shafts (FIG. 5). Two toric joints are provided on the double flange
of cavity B to ensure it is water tight.
This cavity B can be subjected to pressure so that it balances the
force of the water pressure on the toric point of the head.
In the interior of the body, in the cavity A, are installed the
water injection conduit 28 and extraction conduit 29, as well as a
purge conduit 34 which allows the evacuation of the residue when
the center-point sleeve has been implanted, the first injections of
concrete having been carried out, and the waterproofing has been
ensured.
This purge conduit is also intended for the injection of the
concrete into the annular space between the tube 5 and the sleeve 4
when the tube 5 has been implanted in its turn.
The first body 31 is surmounted by a suit intended for implantation
of the first drilling tube 5.
This unit is composed of three essential parts:
a cylindrical frame 33 carrying the blocking handling clamps for
tube 5,
the cylindrical body 32 which contains the tube 5, and
an air chamber 35 is intended to feed air from cylinder 32. A
drilling rod 27 passes through the unit and in case of leaks in the
passages, the water proofing is ensured by instantaneous static
joints.
The first drilling tube 5 is housed in the body 32, it passes
through clamp 36 and descends to the center of the sleeve 4 to the
base of the latter (FIG. 3).
Air pressure on the piston 37 (FIG. 6) effects gradual driving of
tube 5 and the protection of the boring head 26.
This same piston 37 prevents all possibility of encroachment by
water and drilling sludge into cavity E.
The head of water which enters the cavities A and D, namely all the
space below the piston, is balanced by the air injected by pipe
38.
A pneumatic pressure regulating device is connected to the conduit
39 and allows constant high pressure to be maintained inside the
unit and at the same time regulates the head of water within the
limits imposed for good progress of the boring operation.
The upper end of tube 5 is drilled with holes 40 intended for the
evacuation of the drilling sludge and waste produced by the head
26.
Through the undermining work of the head of the sleeve 4, the tube
5 is held in place and steadied by clamp 36 in a position such as
shown (FIG. 3) namely, slightly behind the base of the sleeve
4.
The drilling head 26 which is driven by a rotating table mounted
above the tool unit inside the shafts, breaks down the central
drilling-core cut out by the crown of tools 25 of the center-point
sleeve 4.
The broken-down products are evacuated by the extraction pump which
sucks them out.
During the period of implantation by the center-point sleeve 4,
practically no drilling sludge will pass into the inside of tube
5.
The level of the head of water is thus held at a minimum in order
to allow an easier visual check on the workings through the
port-holes provided for this purpose.
When the pivot 4 is implanted, its crown 24 (FIG. 5) is in contact
with the bed, at least buried in the surface sands, and the
rotation of the shafts is stopped.
The injection of concrete into the outside of the sleeve 4 is then
carried out by means of the holes 23 provided for this purpose.
These first injections are limited to the lateral part of the
center-point sleeve and particularly in the upper part (on average
two-thirds from the top) and under the support flange.
In this first stage concrete is not injected into the base of the
sleeve since it would prematurely flow into the interior, itself,
of the sleeve 4.
When the first injections are finished and the concrete has set,
the boring head 26 carries on the work. As the tube 5 progresses,
it goes down into the drilling under the action of the thrust from
compressed air fed on to the piston 37.
When the tube 5 is in place, the drilling head 26 is drawn up again
under the piston 37.
With the aid of the purge conduit 34 and the extraction pump, the
annular cavity between the tube 5 and the sleeve 4 is cleared of
the sludge therein.
In the annular space the level is held below the lower diaphragm
30. The concrete plug is poured in the annular space limited by the
two diaphragms 30, then for a last time, the residual mud
accumulated at the base of the sleeve is evacuated.
As this moment, by conduits opening into the base of the
center-point sleeve a large quantity of concrete is injected. In
case of particularly soft terrain, concrete can be also injected by
the purge conduit 34.
When all work has been finished, the shaft-rig is implanted and
held in place by the center-point sleeve.
The preparatory work to the boring operation is finished.
In terrain which is particularly soft the first boring tube 5 can
be prolonged as required. But before all dismantling of the
assembly of cylinder 32 allowing the "boring" to proceed, a very
close check of exterior waterproofing of sleeve 4 must be carried
out in order to avoid all possibility of the shafts being inundated
a state which is no longer guaranteed by the cap unit on the head
of the center-point sleeve.
For the implantation of the shaft-rig itself, the work can be
carried out with the help of the floating workshop (FIG. 10).
The floating workshop is essentially intended for the the transport
of material, for assembly and implantation of the shaft-rig on
site, and is accordingly equipped.
This equipment fundamentally consists of a very powerful revolving
table 41, jointed in all azimuths, and with a gantry hoist 42,
especially designed for handling and positioning components on the
axis of the table 41.
The rotating table 41 is intended to drive units of shafting during
implantation of the center-point sleeve 4.
The fore end of the workshop vessel has a normal stem with a
classic hull shape up to the beam. The stern half consists of two
distinct hulls 43, separated by an open space having a V-shape
(FIG. 10).
The space between these two hulls 43 forms a calm-belt and in this
calm space the mounting and the implanting work of the shaft-rig
are carried out.
The rotating table is mounted on four columns 44, two of which are
on each of the two hulls 43 of the vessels.
These columns 44 are both supports and guides for the vertical
movement of the unit.
This vertical movement is ensured by jacks centered in the columns
44.
The two beams 45 (FIG. 12) allow longitudinal movement.
All the articulations are mounted on central rollers in order to
eliminate all possibility of seizing and jamming.
The vertical axle of the table 41 passes through the center of
gravity G of the vessel.
The introduction and the placing of the sleeves in the diagonally
trussed well 41 is ensured by the gantry bridge 42 which is moved
on roller tracks 47 in order to serve all the forward area of the
vessel where the shaft-rig sleeves are stored.
The gantry bridge 42 and its operating cabin are of special design.
The longitudinal and transversal translation are effected by two
sprocket and chain units which allow all handling in a calm or
rough sea.
In a variation of the embodiment, the implantation of the
shaft-rigs is carried out by self-propulsion rotationally of the
center-point sleeve, owing to two pairs of motor-driven propellers
mounted on the base of the shafts (FIG. 1).
In this case, the rotating table 41 no longer serves as a guide for
the shaft casings. The mechanism is very simplified since in this
solution, the centering sleeve of the rotating table is provided
with centering rollers on which the sleeves of the shaft-rig rests
and rolls.
In another variation of the embodiment of the implantation of
shaft-rigs, the center-point sleeve 4 is driven in rotation by the
means of a worm drive 49 and 50 (FIG. 8), thus producing a
self-drilling shaft-rig. These last two types of implantation are
particularly recommended in the case of medium and very great
depths.
The general arrangement of self-drilling rigs are similar to those
of the two first embodiments, given the need to balance the couple
created by the gear and worm screw unit on the outside of the base
of the rigs, the center-point sleeve must be stabilized by brakes.
These brakes consist of two diametrically opposed paddles installed
in such a way that they can be worked as required, from inside the
shafts.
In this solution the entire tooling, intended both for recuperation
of sludge and for the positioning of the first drilling tubes, is
necessarily mobile in relation to the sleeve of the shafts which is
fixed. The evacuation of sludge and all other products must thus be
made first in this tooling and, next, the rotation of the
center-point sleeve 4 is stopped and the drilling products
accumulated in this space, are evacuated to the outside joining the
part to be emptied with the evacuation orifice, provided with this
in view, in the sleeve of the shaft-rig, by a hoop, the inlet and
outlet being blocked by the working valves.
These three types of shaft-rigs have one point in common. Their
whole is one sleeve which emerges on the surface. On the platform
which caps this end, the classic drilling derrick can be
positioned.
This solution can be retained in the case of slight depths, as the
length of the jointed rods from the surface to the attack on the
underwater bed are not prohibitive.
In the case of medium and very great depths, it is preferable to
utilize a jacked bridge (FIG. 4) installed inside the shafts.
The design of this handling gear allows the need for the libe
ration of the center of the shafts to be omitted.
Similarly, the rotating table installed inside the shafts is
conceived in such a way that it can also be omitted or put into the
position for working in at least two different stages, on the one
hand, above the tooling when implanting the center-point sleeve 4,
and, on the other hand, a little nearer the head of sleeve 4, when
the tooling is dismantled and replaced by that intended for the
boring.
The placing of the jacked bridge can follow variations in
gradient.
On the other hand, when the workshop vessel has carried out its
work on the shaft rigs, it must be freed to carry out other
implantations as this is an extremely costly unit and, therefore,
its immobilization must be very short. Also, it is anticipated to
replace this workshop ship with a pontoon workshop (FIG. 13).
The workshop pontoon is equipped with all necessary gear for
drilling and machines intended to feed the shafts by motive force
(electricity, compressed air and hydraulic energy), it is provided
with all kinds of required installations for the comfortable
lodging of crews and drilling teams.
This pontoon would take the place of a workshop vessel. It must, as
a unit in itself, support the sleeved shaft. Thus, its emerging
part must be girdled with an articulated unit 51in all azimuths, as
the ship, but in which the driving of the shafts will be replaced
by a simple sleeve with central rollers 52. This sleeve and its
outside support would be in two parts, joined by bolts in such a
way as to be able to be mounted on the shaft sleeve of the
shaft-rig by its traverse.
The vertical movement due to the tides and swells will be made
directly on the sleeve of the shaft-rigs which serve the roller
track by the central rollers 52.
The pontoon is equipped with windlasses, fore and aft, handling
winches and the necessary capstans for all operations at the same
time, when being put into place and during all drilling work.
The end and side propellers 53 allow a stabilization of the whole
unit and help to maintain the axis substantially in the center of
gravity. It also permits the vessel's head to be held on to the
swell.
As shown (FIG. 13 and 13a) this pontoon is in two jointed parts and
flexibly held together by hinged joints.
When the collar of the shafts is engaged in the space reserved for
it, the aft part of the pontoon swings about the axis 54 and closes
and locks itself in the devices provided with this in view.
The transport, mooring and the lifting of anchors intended for
staying the shaft-rigs is a very important work. Also in order to
complete this installation, it is necessary to produce a tumbler
(FIG. 14 and 9).
The tumbler is a small boat specially designed and equipped for the
transport, the casting, and weighing of anchors and buoys intended
for staying shafts. It also allows the carrying out of the mooring
of these buoys to shafts.
The tumbler is fundamentally composed of a hull consisting of two
caissons 55, joined together by a series of cradles 56. Each cradle
56 supports a group consisting of one buoy and one kentledge
57.
The whole is straddled by a toric bridge 58, which moves on two
roller-tracks 59. This movement is carried out by casings, each end
of which is provided with a brake 60 which allows an absolute
blocking into place of the gantry bridge.
The movement of the bridge is ensured by a winch 61, and the chain
and sprocket assemblies 62, 63 and 64.
Each of these roller-tracks is provided with two or four mobile
intermediary supports which are intended to support to the nearest
extremities of the roller housings 66, the tube, in order to ease
the efforts due to lifting a kentledge 57. These intermediary rests
are blocked, as required, as is the deck of the vessel.
The gantry bridge is provided with such supports. These are
arranged on the lower part of each housing 66 coming into contact
with the points foreseen on the deck.
The entire frame work of the gantry contains the winches intended
to handle the mooring and the weighing of kentledges and buoys.
The shafts of chains are arranged in each of the caissons which
form the hull of the vessel.
Such an installation allows the implantation of underwater
recuperable bases intended for the extraction of petroleum and gas
or any other products accumulated in the soil itself, or on the
surface of the sea bed, by means of shaft-rigs open to the air.
These same shaft-rigs can be employed for the implantation of bases
intended for the anchoring of support pylons, floating or fixed
islands or all other maritime surface installations.
These shaft-rigs allow drilling crews to work at the bottom of the
shaft head under conditions identical or similar to those
encountered during land drillings. In fact, the work at the bottom
is carried out in the open air, namely in all circumstances at
atmospheric pressure.
When the drilling is finished, three hypotheses can be
demonstrated: the drilling is unproductive (no product or non
profitable products), the drilling permits a profitable
exploitation where the shafts remain in place for the duration of
the exploitation of the drilling. In the case where the drilling is
unproductive, it is indispensable to immediately recuperate the
whole of the installation apart from the center-point sleeve 4
which is implanted for good in the sea bed.
All the tools intended for drilling are dismantled. The head of the
sleeve 1 is stripped of all accessories. It is then capped with a
cylindrical chamber or a "nose-cap" which is connected to the base
of the shaft-rig by a flange. This "nose-cap" carries a tool
essentially consisting of a set of keys 68 which, passing through a
stuffing-box and balanced by compression springs, mounted on
bearings, can be operated from inside the shaft-rig.
These keys are intended to undo the bolts 69 which join the shafts
to the center-point sleeve by means of flanges.
In order to carry out this dismantling operation, the water ballast
tanks are filled up and, consequently, allow pressure to be
transferred from one flange to the other.
When the screws are taken out, the water rushes into the cavity and
the head of the sleeve. The force thus produced by the water on
this free surface cooperates with the give of the water ballast to
slacken off the base of the shaft from the head of the center-point
sleeve.
Owing to the give provided by the water ballast, the shaft-rig is
brought up again, sleeve by sleeve, and recuperated on the workshop
vessel.
Re-equipped with a new center-point sleeve, it can them be put back
into service again.
In the second case, where the drilling allows a profitable
exploitation, the head of the center-point sleeve 4 is blocked up
by a base plate 70. On this base plate 70 is placed the drilling
material and all its accessories. This unit is then held within a
hermetic space consisting of a cylindrical chamber 71 closed by a
cover provided with a valve and connected to the head of the
center-point sleeve by studs.
The cover is provided with a valve and a manhole 73.
The joints of the elements constituting the drilling material is
made through the wall of the body 71 and the blocking off is
ensured by the valves which can be remote-controlled.
The whole of the chamber 71 and of its cover 72 is capped in its
turn by a second cylindrical chamber 67 connected to the bottom of
the shafts, as indicated in the preceding case, which allows
recuperation in this case.
In the second hypothesis, it would be necessary to periodically
visit the drilling material. Thus a nacelle 74, consisting of a
unit, is foreseen: living space, water ballast tanks, such
machinery to be capable of, at all times, being brought into
equilibrium inside itself, with the environment in which it is
found.
A living chamber 75, specially arranged, allows several men to live
there at normal atmospheric pressure for several hours or several
days.
This nacelle which can be guided by remote control or connected to
the surface by means of a cable, or be independent and piloted by
its occupants, sits on top of the chamber 71 fitting to its cover
72 by centering on the studs and on the rim with the help of the
volume in the water ballast tanks 76.
A device of special nuts and studs allow it to be hermetically
fixed on the head of the shaft.
An air purge clears water from cavities 77 and 78 at the same
time.
When the nacelle is in place and the waterproof state has been
verified, the plugs 79 and 73 are lifted out to give access to the
drilling material.
When work is carried out, the plugs are replaced and the nacelle
freed to rise back to the surface.
For particular reasons of exploitation, it can be used to maintain
the whole shafts rig in place during the whole duration of the
exploitation of the drilling which is carried out according to the
third case envisaged above.
This method allows an easy access to the head of the shafts which
remain in the open air.
In this case, the workshop ship must be freed and replaced by the
workshop pontoon, foreseen with this in view.
When the exploitation is finished, it will be necessary to
recuperate the shaft-rig. This operation can be performed according
to the pro cess in the first case.
It is obvious that the invention is not limited by the example
described and illustrated above, from which can be anticipated
other forms and other methods of the embodiment without departing
from the scope of the present invention.
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