GB1585365A - Rig transport - Google Patents

Description

(54) RIG TRANSPORT (71) We, JAMES G. BROWN AND ASSOCIATES, INC., a corporation organised under the laws of the State of Texas, United States of America, of P.O. Box 20129, Houston, State of Texas, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a drilling rig for offshore use allowing for a lightweight, openwork structure, thereby eliminating the necessity for the rig to float and allowing versatile positioning of the drill mechanism.

A mobile jack-up drill rig is the most stable, versatile and economical offshore drilling unit for operating in water depths of fifty to four hundred feet. In all but the worst sea conditions, a jack-up rig is a stable platform from which drilling operations can be performed efficiently well above the top of the waves. In a moderate storm, a drill ship or a semisubmersible usually must shut down drilling operations due to the high roll angle and pitch angle caused by the wind and waves. A mobile jack-up drilling rig is stable because it is set on the sea floor, which is not affected by the surface sea conditions. It is versatile because it is not limited to any one bottom condition, water depth or geographic location.A mobile, offshore, jack-up drilling rig of the prior art has one disadvantage in that it becomes less competitive economically to build for water depths greater than four hundred feet. To increase the operating depth of a jack-up drill rig using present technology, the distance between the legs is usually made greater, thereby necessitating the addition of more steel between the legs. Additionally, as more steel is added to the hull and to lengthen the legs, more steel must be added to the legs to support the extra weight of the hull and the extra length of the legs.

Several types of jack-up drilling rigs have been known and used before, and typical examples thereof are shown in U.S.

patent no. 3,183,676 issued May 18, 1965, to R. G. Le Tourneau; U.S. patent no.

3,466,878 issued September 16, 1969 to N. Esquillan et al; and U.S. patent no.

3,093,972 issued June 18, 1963 to M. R.

Ward Jr. None of these devices, however, teach either a drilling, workover, or crane openwork jack-up rig that is nonseaworthy.

Several types of circular orientating systems have been known and used before, and typical examples thereof are cranes which rotate on an upper circular skid rail and well treatment facilities that mount on an ancillary portion of the hull. None of these teach the use of a curved skid rail in drilling operations to locate drilling equipment.

According to the invention we provide a rig for use in supporting and using equipment above the ocean bottom, comprising: a body, said body being formed by a substantially completely open network of truss-like members, said members forming open inner and outer vertical and horizontal peripheries of said body which permit wind and light to pass through said body; leg means connected to said body for supporting said body above such ocean bottom while such equipment is in use; platform means mounted on said body for supporting at least some of such equipment; said leg means including elevation means for elevating said body above such ocean bottom and connection means for connecting said elevation means to said body; said body having structural negative buoyancy; and said leg means includes only three legs.

The present invention uses a very simple but highly effective design for a jack-up rig including a light openwork rig superstructure to economically extend the water depth capability of jack-up drilling rigs by reducing the weight supported by the legs per foot of water depth as well as to reduce the weight of designs for present water depths. Conventional legs, such as, for example, cylindrical, three chord triangular or four chord square legs, are connected through the jacks to the superstructure to form the jack-up rig. The superstructure includes a truss and member stiffened structure of various configurations, such as, for example, triangular or cross-shape, the structure having negative buoyancy. In the preferred embodiment, the superstructure has no bottom to form a hull.

In a preferred embodiment, the platform structure may further be equipped with a curved skid rail such as a circular skid rail to permit rotation of the drill works about the center of the skid rail for azimuthal positioning of the drill works.

The circular skid rail is, moreover, used in conjunction with conventional skid rails being mounted on the circular skid rail to provide an accurate mechanism for positioning the drill stem at the desired location for the drill hole.

Constructional embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which like parts are given like reference numerals and wherein: Figure 1 is a plan view of a first embodiment of a rig in accordance with the present invention; Figure 2 is a cross-sectional view of a circular skid rail taken along section lines 2-2 of Figure 1; Figure 3 is a partial top view of the rig of Figure 1 showing a drill floor in place on the upper skid rail; Figure 4 is a side, partial, cross-sectional view of the rig taken along section lines 4-4 of Figure 1 and including the upper skid, draw works, drill floor, and derrick in place; Figure 5 is a side elevational view of the rig of Figure 1; Figure 6 is a plan view of a second embodiment of a rig in accordance with the present invention;; Figure 7 is a side section taken along section lines 7-7 of Figure 9; Figure 8 is a side, cross-sectional view taken along section lines 8-8 of Figure 6 and including a derrick and draw works in place; Figure 9 is a partial top view of the rig of Figure 6; Figure 10 is a plan view of a third embodiment of a rig in accordance with the present invention but not showing any drill works; Figure 11 is a side cross-sectional view taken along section lines 11-11 of Figure 10 also showing a drill works and pipe ramp and ladder in place; Figure 12 is a side, detailed view, partially in elevation and partially in crosssection, of the drill works mounted on the lower skid rail of the rig of Figure 10; Figure 13 is a plan view of any one of the three embodiments showing the relation of a rig transportation vessel to preload tanks of a rig (the superstructure of the rig not being shown);; Figure 14 is a side section taken along section lines 14-14 of Figure 13 showing the vessel in position to receive the rig; Figure 15 is a side section taken along section lines 14-14 of Figure 13 showing the vessel carrying the rig; Figure 17 is a plan view of the third embodiment showing the rig as a production platform; Figure 18 is a side elevational view of the rig shown in Figure 17 with modules located on the superstructure and suspended below the superstructure; Figure 19 is a plan view of a triangular shaped, non-seaworthy rig with a reinforcing structure for cantilever operation using the skid structure shown in Figure 10; and Figure 20 is a side, elevational view of a cross-shaped cantilever rig showing drilling equipment for sustaining drilling operations without tender assistance and with mat engagement for footing on the ocean bottom.

A rig in accordance with the present invention may be used to support apparatus offshore where it is desired to employ a mobile jack-up rig, e.g. in deep waters, such as, for example, greater than four hundred feet. Operation of the rig at great water depths is accomplished by the use of an openwork superstructure or body for the rig thereby gaining a reduction in weight. A particularly important area of application of the present invention is in deep water drilling, crane support or work over, wherein mobile, openwork jack-up rigs are used in a tender assisted or self sustaining manner. However, it should be realized that the present invention could be applied to, for example, any application where it is desired to support and suspend apparatus above a water surface in water depths that may vary from a few feet to deep water.

In the preferred embodiments of the present invention, the openwork superstructure of the rig is formed using truss members.

In the first two embodiments, positioning of the drilling equipment is accomplished partly through the use of a circular skid rail for azimuthally orienting the drilling equipment.

All three embodiments are constructed to permit mounting of the rig, including the superstructure, legs, and preload members, on the deck of a ship, barge, or semisubmersible as a single unit for transportation purposes. Any of these preferred embodiments of the rig may also be transported by dismantling the rig and shipping it in sections with reassembly by welding, bolting, or riveting at a remote location.

The rigs may be tender assisted, and the tender may be a semisubmersible, barge, or ship which could also be used to transport the rig and the equipment to be placed on the rig. The tender may also be used to preload the rig.

As shown generally in Figures 1, 4, 5, 6, 8, 10, 11, 12 the three embodiments of the rig numbered 1, 2, 3 comprise three basic elements. Rig 1, 2 or 3 includes leg structures 4 which may be of a truss design such as a three chord triangular, a four chord square, or round or cylindrical shaped as shown. Rig 1, 2 or 3 further includes an openwork body or superstructure of any shape such as triangular 5 (Figure 1) cross 6 or 7 (Figures 6 and 10) maltese cross, square (not shown) or rectangular (not shown). The body 5, 6 or 7 may be a trussed structure as shown or a box beam structure or any other suitable construction. Rig 1, 2 or 3 further includes a skid rail system 8, 9, 10 respectively for supporting drilling equipment 11.

Drilling equipment 11 includes a drill floor 50. Usually, the only machinery located on drill floor 50 will be drilling machinery such as, for example, derrick 53 sitting on bases 58, draw works 60 and rotary drive means (not shown).

Additionally, one crane (not shown) may be located on the rig or the drilling equipment 11 may be used in place of the crane. All other equipment such as, for example, spare drill pipe, mud pumps, and living quarters may be located on a tender 242 which may be either a barge, ship or semisubmersible connected to the rig 1, 2 or 3.

Embodiment 1 Referring particularly to Figures 1, 2, 3, 4 and 5, there is shown a rig 1 of triangular configuration in plan. Leg structures 4 are connected by truss frames 12, 13 and 14 to form a lightweight, openwork body or truss structure 5 of a triangular shape, truss structure 5 having a negative buoyancy without preload tanks 20. The components of truss frames 12, 13, 14 may be of any suitable construction, such as, for example, structural tubing or wide flange beams.

Each leg structure 4 comprises three elements, a leg 16, jacks 18, and preload tanks 20 supporting jacks 18. Legs 16 terminate in the ocean floor 24 with spud cans 26 having projections such as, for example, projections 28 (Figure 16) stabbed into the ocean bottom 24 to support rig 1 through cylindrical legs 16. Teeth or openings (not shown) on legs 16 are engaged by jacks 18 located on preload tanks 20 to fix the length of the legs extending below preload tanks 20. The preload tanks 20 are attached to truss structure 5 by truss members 12, 13, 14 at the intersection of the members thereby forming the platform. Reinforcing beams 22 are provided at the intersection of truss members 12, 13 14 at leg structures 4 to distribute the leg load, to support the drilling works 11 substructure, and increase the strength of truss structure 5.

Skid rail system 8 is mounted on truss structure 5 and includes a lower circular skid rail 30. Skid rail 30 has a horizontal member 32 (Figure 2) welded by welds 34 to a vertical member 36 resting on truss frames 12, 13, 14 and reinforcing beams 22. The intersections of circular skid rail 30 with the vertical planes of the inboard and outboard sides of the truss frames 12, 13, 14 usually occur at the location of members 48 of the truss structures. Skid rail system 8 also includes upper parallel skid rails 40 of suitable construction, such as, for example, structural tubing or wide flange beams mounted on lower skids 42. Lower skids 42 form a channel 43 in cross-section having partial opening 46 to slidingly engage and hold horizontal member 32 of circular skid rail 30.Sufficient clearance is provided with the opening 46 to permit bidirectional rotation about the centre 44 of lower circular skid rail 30 as shown by directional arrows 47 for azimuthal orientation.

As best seen in Figure 3, upper skids 54 which have the same cross-section as lower skids 42 are connected slidably to horizontal member 56 of the upper skid rails 40 with sufficient clearance for movement thereon. Drill floor 50, having a hole 52 therethrough sized to permit lowering of a drill string (not shown) at the center thereof, is mounted on the upper skids 54, usually by welding. Therefore, drill floor 50 is bidirectionally moveable along upper skid rails 40 as shown by directional arrows 51. Apparatus well known in the art, such as, for example, shown in brochures of The Rig Skidding Jack manufactured by Joe Stine, Inc. of Houston, Texas or Hydraulic Gripper Jacks manufactured by Hydranautics and distributed by Ocean Supply, Inc. of Houston, Texas may be employed to cause movement of the skids and apparatus thereon with respect to the skid rails.

A derrick 53 rests upon the drill floor 50 with the base 58 of the derrick 53 located over the upper skids 54. Draw works 60 are also located on drill floor 50.

Directional arrow 62 indicates the typical path for a ship 64 to take in movement to engage rig 1 for transportation and location purposes. The ship 64 may also approach rig 1 from either of the other two sides in a similar manner.

Embodiment 2 Referring particularly to Figures 6 and 8, rig 2 is a cantilever type rig of a "T" (or cross) configuration rather than triangular. It has the same leg structure 4 as that of rig 1.

Referring to Figures 6, 7, 8, and 9, rig 2 includes an openwork truss structure 6. Truss structure 6 includes two truss frames 100, 102 intersecting each other approximately perpendicularly at 101 with reinforcing members 104 located at the intersection. The components of the truss frames are of the same type as rig 1.

The ends 103, 105 of truss frame 100 and end 107 of the truss member 102 connect to preload pods 20.

Skid rail structure 9, mounted on truss frames 100, 102, and reinforcing members 104, includes a lower circular skid rail 30 connected to lower skid 42 as previously described for Embodiment 1 to permit rotation of upper skid beams 40 about center 44, lower skid 42 being connected to the upper skid beams 40. An upper skid 106 is mounted by welding or other suitable means on horizontal member 56 of upper skid rails 40 forming a channel about horizontal member 111 of a lower flange 110. Upper skid 106 may be formed in two halves connected to the lower beam 110 of a cantilever beam structure 112 by welding with sufficient clearance to permit cantilever beam structure 112 to be moveable on upper skid rails 40 in the directions shown by directional arrows 113.

Because this is a cantilever rig, drill floor 50 is mounted by welding or other suitable connection to upper member 114 of cantilever beam structure 112. Lower member 110 and upper member 114 of cantilever beam structure 112 are joined by vertical members 115. Drill floor SO, although mounted on upper member 114 of cantilever beam structure 112, is not mounted over upper skid 106. Therefore, the resting points 116 of base 58 of derrick 53 are not normally over upper skids 106.

Circular skid rail 30 permits drilling equipment 11 on drill floor 50 to be rotated about center 44 to position it azimuthally to any angle within 360 , including, but not limited to, the cantilever position for drilling as shown in Figure 6. Before or after rotation, movement of cantilever beam structure 112 along upper skid rail 40 may be used to appropriately position drill hole 52 with respect to sea floor 24.

To prevent contact between drill floor 50 and legs 4 during rotation, drill floor 50 may be moved at least partially inwardly toward the center 44, using upper skid 106 operating with cantilever beam structure 112, prior to rotation about center 44.

This would depend on the length of truss frame 100. Movement of the skids with respect to the skid rails may be caused by apparatus as identified in Embodiment 1.

Embodiment 3 Referring now to Figures 10, 11 and 12, there is shown a rig 3 having an openwork truss structure 7. Truss structure 7 comprises reinforcing member 200 connected to longitudinal truss frame 202, transverse truss frame 204 and cantilever force distribution truss structures 206. Truss structures 206 forms a well 243. Truss structure 7 is in the shape of a cross thereby permitting drilling equipment 11 to be operated over the well 243. The components of the truss frames are of the same type as in the rig 1. The ends 203, 205 of truss frame 204 and the end 207 of reinforcing member 200 are connected to preload tanks 20 to support truss structure 7 on leg structure 4. Also the ends 209, 211 of the structures 206 connect to preload tanks 20 to further distribute load into the leg structure 4.

As previously discussed, jacks 18 mounted on preload tanks 20 engage legs 16 thereby connecting them to preload tanks 20 and therefore to truss structure 7.

In Embodiment 3, the ends of the lower portion of legs 16 below preload tanks 20 are connected to a base 208. Therefore, as legs 16 are jacked downward by jacks 18, the base 208 will come to rest on the ocean bottom 24 thereby supporting the legs 16 and, hence, the rig 3 above the water surface 210 in the same manner as the spud cans 26 for rigs 1 and 2.

Skid system 10 permits fore and aft movement and transverse movement of drilling equipment 11. It comprises lower skid rails 212 having horizontal members 213 and vertical members 214 for fore and aft movement 224. A carriage 216 is connected by lower skids 218 to the horizontal member 213 of lower skid rail 212. Lower skids 218 are connected to carriage 216 at lower carriage beams 220 by welding or other suitable means to form a channel of suitable size for sliding engagement with horizontal members 213, permitting movement of the drilling equipment 11 in the general direction indicated by arrows 224. Vertical structural support ing members, such as, for example, wide flange beams 226 and 227 of carriage 216, support upper beams 240 on the wide flange beams 220 with surface 230 of vertical wide flange beams 226 forming upper transverse skid rails.Upper skids 222, as with the upper skids 106, are of two sections 234, 236. The top of these sections are connected by welds to an upper carriage 228 and the bottom of the sections have an opening to form a channel 238. Channel 238 is sized for slidably engaging skid surfaces 239 of the upper carriage 228 with upper skid rails 230 and for holding upper skid 230 within channel 238 to permit transverse movement of the drilling equipment 11 as generally shown by direction arrow 232.

Floor 50 mounts directly on beam carriage 228. Therefore, bases 58 of derrick 53 may be positioned on floor 50 directly above upper skids 222 to distribute the weight of the derrick 11 through beams 240 and upper carriage 228 to skids 222, and 218 and thence to the truss structure 7 of rig 3.

As with rigs 1 and 2, rig 3 is a tender assisted rig using a tender 242, which may be a barge or semisubmersible for rough seas or ship. The use of the semisubmersible for this non-drilling application would require its base portion 244 to be less strongly reinforced than a semisubmersible adapted for drilling.

Therefore, it may be less expensive in combination with an openworks rig than a semisubmersible adapted for drilling.

Tender 242 is connected to drill works 11 by pipe ramp and personnel transportation facilities 246 such as, for example, a ladder.

Referring to Figure 12, the height between drill floor 50 and lower skid rail 212 may be such that drilling equipment 11 may be used to hoist and locate modules of equipment such as, for example, mud pumps and quarters (Figures 17, 18). These modules may be unloaded from a ship (not shown) located under well 243 by the drilling equipment, suspended under drill floor 50 and moved along the skid system 10 to the appropriate position, and located on truss member 202 (Figures 17, 18).

Rig Transportation Referring particularly to Figures 13, 14 and 15, a vessel, such as, for example, barge or semisubmersible or ship 300 comprising a hull 302 and deck 304 is used to transport rigs 1, 2 or 3 to drilling or other work sites. A plurality of winch driven lifting mechanisms 301 are provided on deck 304 and pinned to hull 302 to engage preload tanks 20 and resiliently bear the weight of rigs 1, 2 or 3 on ship 300 as legs 16 are jacked up off the ocean bottom.

Mechanisms 301 include winches 306.

Each winch 306 comprises a drum 305 with an axle 307 therethrough located on deck 304. Wire rope 309 is wound on drum 305, and a part 308 extends from winch 306 to pulleys 310, 312 mounted on a preload tank 20 of a leg structure 4.

Pulleys 310, 312 are located in the preload tank 20 to align guideline 308 within socket 314. Socket 314 includes a lining 313. Socket 314 forms indentation opening 316 in the preload tank 20 bounded by flat surface 322 and is sized to receive a semicircular steel ball 318 therein. Steel ball 318 includes an anchor 332 for attachment of line 308.

Steel ball 318 is rotatably mounted in a holder 324 of a beam 326 and supported by beam 326. The outboard surface of beam 326 is covered with a rubber bumper 330 located and sized to resiliently contact surface 322 of preload tank 20 (Figure 15) for support.

Beam 326 is hinged to a stand 334 by a hinge pin 336, permitting beam 326 to rotate about hinge pin 336 as generally shown by direction arrows 338. Beam 326 is of sufficient length for steel ball 318 to engage socket 314 and fill opening 316.

Base 334 is slidingly mounted on skid rails 340 with a sufficiently low co-efficient of friction to permit the base 334 to slide on skid rails 340 while bearing the full weight of rig 1, 2 or 3. The direction and movement of base 334 is generally indicated by arrows 342.

Stops 341, 343 are provided on the inboard and outboard sides of base 334 to restrict its movement along skid rails 340. Each stop 341, 343 is provided with a resilient pad or spring 345 of sufficient resiliency to cushion the impact of base 334 against the stop 341, 343. Resilient pads 347 are provided on the inboard side of base 334 at a position to be juxtaposed with resilient pads 345 upon impact of base 334 with stops 341. Extensions 349 are disposed on the lower end of base 334 facing opposite deck 304 with pads 351 mounted thereon facing opposite pads 345 of stop 343.

The outboard end 344 of beam 326 includes support extensions 346. Support extensions 346 are supported by the upper end of 353 of a support bar 348, rotatably connected thereto by a hinge pin 356.

Support bar 348 is rotatably connected at its lower end 354 by a hinge pin 350 to a hull support 352 by an extension 355 mounted on the upper end of support 352.

A shock absorber 358 is provided as a part of support 348 with sufficient resiliency to dampen the impact forces applied by rig 1, 2 or 3 to ship 300 as the rig weight is placed on beams 326 both initially and by sea action.

A rubber pad 370 is located on base 334 between base 334 and beam 326 with additional resiliency to absorb the impact forces and limit rotation of beam 326.

As best seen in Figures 1, 6, 10, 13, when rigs 1, 2 or 3 are to be transported to a location for drilling or other work a ship 300 approaches rig 1, 2 or 3 in the general direction of arrow 62, i.e. from a side between two legs. Guidelines 308 (Figures 14, 15) are then strung for each leg structure 4 from drum 305 of a respective winch 306 over pulleys 310, 312.

From pulleys 310, 312, guidelines 308 are then strung, through sockets 314 to connections 332 of steel balls 318. This may be done for all three leg structures 4 simultaneously. The connection of the guidelines 308 through the pulleys 310, 312 on the preload tanks 20 may be done while the ship 300 is located at a considerable distance from the rig 1, 2 or 3, such as, for example, one hundred feet, without danger of collision of the ship 300 with the rig 1, 2 or 3.

The winches 306 are then activated drawing the ship 300 under preload tanks 20 and rotating beams 326 toward preload tanks 20 thereby expanding shock absorbers 358 as steel balls 318 are drawn to sockets 314. When the steel balls 318 have filled spaces 316 of sockets 314 and surfaces 322 have come in contact with surfaces 328 of rubber bumpers 330 at the outboard ends, thereby centring port and starboard bases 334 along skids 340 between stops 341 and 343, jacks 18 may be activated.

As best seen in Figure 15, when jacks 18 are activated, they raise the legs 16 to the required clearance above water surface 210 thereby placing the weight of rigs 1, 2 or 3 on ship 300. This will cause each beam 326 to quickly rotate downwardly until shock absorbers 358 and rubber pads 370 are compressed to firm resistance, absorbing the shock of the impact force of the rig weight.

Winches 306 may have their tension varied so that the ship 300 and lifting mechanisms 301 will stay substantially centred between the port and starboard tanks 20. As the weight of rigs 1, 2 or 3 is applied to ship 300, port and starboard bases 334 will move farther along skids 340 to adjust the spacing between port and starboard steel balls 318 to the spacing between the corresponding sockets 314 of preload tanks 20.

After legs 16 have been jacked to the extent necessary for transportation and the rig secured on ship 300, ship 300 may then carry the rig 1, 2 or 3 to its location.

Upon arriving at the drilling site, jacks 18 are again activated to lower legs 16 downwardly towards the bottom 24. As legs 16 are lowered, and move farther below the hull 302 of ship 300, the lower portion of leg 16, either base 208 or spud cans 26, will experience increasingly greater transverse and vertical movement caused by the pendulum effect of movement of ship 300 under wave action. Therefore, as either base 208 or spud can 26 reaches bottom 24, there will be impact reactions caused by the movement of the legs 16 being stopped by the ocean bottom 24. To avoid excess impact forces on the legs, the landing operation is usually carried out during periods of relatively calm seas.

Even under these circumstances, there is a high potential with heavy, seaworthy jack-up rigs, whether or not mounted on a ship, to shear, bend or otherwise damage a leg upon contact of the leg with the ocean bottom 24. However, because rigs 1, 2, 3 are lightweight, having openwork bodies requiring less steel for the body and consequently less steel per foot of leg, and because shock absorbers 358 and pads 370 are provided to absorb impact forces, the danger of impact forces damaging legs 16 is reduced, and the legs may be set on the ocean bottom in heavier seas.

After the base 208 or spud cans 26 have reached the bottom, jacks 18 will continue to lift rigs 1, 2, 3 above the surface 210 of the water and deck 304.

If insufficient or no preload tanks are provided, the rigs may be jacked up almost off the buoyant ship 300 and preloaded using the weight of the buoyant ship.

After the rig is no longer dependant on the buoyant ship 300 for support, the ship 300 may be withdrawn a sufficient distance from the rig to permit disengaging of guidelines 308. This withdrawal is usually performed under tension of the guidelines 308 and the ships' engines and/or standby tug boat engines (not shown) to safeguard the ship 300 from colliding with the rig.

After sufficient extension guidelines 308 are released from ball 318 and pulleys 310, 312. Ship 300 can then be disengaged and may then become tender assisting if desired, acting as tender 242.

Operation of the Rig After the rig 1, 2, 3 is properly located, elevated, and secured to the ocean bottom 24, such as, for example, by use of preload tanks 20 to force extra load on leg structures 4, and the equipment located on floor 50, if it was not transported on floor 50, the rig 1, 2 or 3 is ready for drilling.

The drilling equipment 11 may be oriented with regard to the selected position on bottom 24 where drilling is to commence.

To orient the rig 1, lower skids 42 are activated to azimuthally position drilling equipment 11 on circular skid rail 30.

Upper skids 54 are then activated on upper skid rails 40 to position the drill works 11 along the diameter selected through orientation on circular skid rail 30. To orient rig 2, lower skids 42 are first activated to position drilling equipment 11 azimuthally on a selected diameter of circular skid rail 30. Lower flange 110 is then moved in upper skids 106 to position drilling equipment 11 along the diameter selected or along the projection of the diameter beyond the perimeter of circular skid rail 30. In this manner, drilling equipment 11 may become cantilevered as shown in Figures 6 and 8 or may work in the areas between the sets of legs. To orient rig 3, drilling equipment 11 is oriented by first activating lower skid 218 for fore and aft movement of drilling equipment 11 bringing drilling equipment 11 over well 243.After lower skid 218 has been properly positioned along lower skid rail 212, upper skid 222 is activated to transversely position drill works 11 within well 243 to locate hole 52 over the desired position (not shown) on bottom 24.

Referring to Figure 17, after drilling is completed and the wells are also completed, the drilling equipment 11 may be removed. The rig, such as rig 3, because of its lightweight, openwork body lowering construction cost, may then be economically converted to a production platform.

Modules such as crew quarters 400, generators 402, machinery 404, and mud pits and machinery 406 may be loaded on truss member 202 (Figure 17) by drilling equipment 11 as described in Embodiment 3 or by an external crane (not shown). These and additional modules 408 may also be suspended from truss member 202 (Figure 18). The drilling equipment 11 may be removed, if required, either prior to or after the mounting of the modules. Preload tanks 20 may be used for storage of fuel oil and drilling water.

Referring to Figures 19 and 20, modules may also be used to provide the necessary facilities to permit jack-up rigs having openwork bodies to be self sufficient, requiring no tender assistance. As best seen in Figure 19, rig 416 is a triangular shaped, slot rig using a superstructure similar to a combination of that of Embodiments 1 and 3. Rig 416 is also provided with leg structure 4 and, additionally, reinforced slot structure 206 forming well 243 such as that of Embodiment 3. A skid system 10 is also provided such as that of Embodiment 3.Superstructure 3 includes support modules to provide all necessary support for drilling operations such as quarters 400, generators 402, machinery 404, mud module 406 including mud pumps 412 and mud pit 413, cranes (not shown) on crane pedestals 409, pressure tanks 410, cement unit 414, shale shaker degasser and desilter and desander 418, and heliport 420. Fuel oil and drill water may be stored in preload tanks 20, if necessary.

As best seen in Figure 20, rig 422 is a cantilever type rig using a superstructure similar to that of Embodiment 2. Rig 422 is also provided with leg structure 4 including a base 208 such as that of Embodiment 3. Additionally, rig 422 includes a cantilever beam 112 such as that of Embodiment 2 and an upper skid system 222 such as that of Embodiment 3.

The mud pump and mud pit module 406 is located below the pipe rack and in the superstructure, resting on structural members 424.

Although the system described in detail supra has been found to be most satisfactory and preferred, many variations in structure and method are possible. For example, the legs can be of any shape including round, three chord triangular, or four chord square legs of either solid or truss structure. The rig may be square or rectangular in plan with four leg segments used instead of three. During transportation, the rig may be dismantled and carried on the deck of a tender or transportation vessel so that it can be transported through narrow channels or rivers. Any type of transportation vessel such as a ship, barge, or semisubmersible may be used. Additional machinery may be located on the floor 50 of the rig to minimize or eliminate tender assistance. Box beams may be used instead of truss structure. Either spud cans or bases may be used with any of the rigs. The platform can be mounted so that it does not revolve about the centre of the circular skid rail 30. The rig may be used to support cranes, quarters, or other apparatus in addition to or instead of the drill works. All of the equipment located on floor 50 may be transported separately on the same or a different vessel. The skid rails may be of any curved shape.

The above are exemplary of the possible changes or variations.

WHAT WE CLAIM IS: 1. A rig for use in supporting and using equipment above the ocean bottom, comprising: a body, said body being formed by a substantially completely open network of truss-like members, said members forming open inner and outer vertical and horizontal peripheries of said body which permit wind and light to pass

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (23)

**WARNING** start of CLMS field may overlap end of DESC **. To orient the rig 1, lower skids 42 are activated to azimuthally position drilling equipment 11 on circular skid rail 30. Upper skids 54 are then activated on upper skid rails 40 to position the drill works 11 along the diameter selected through orientation on circular skid rail 30. To orient rig 2, lower skids 42 are first activated to position drilling equipment 11 azimuthally on a selected diameter of circular skid rail 30. Lower flange 110 is then moved in upper skids 106 to position drilling equipment 11 along the diameter selected or along the projection of the diameter beyond the perimeter of circular skid rail 30. In this manner, drilling equipment 11 may become cantilevered as shown in Figures 6 and 8 or may work in the areas between the sets of legs. To orient rig 3, drilling equipment 11 is oriented by first activating lower skid 218 for fore and aft movement of drilling equipment 11 bringing drilling equipment 11 over well 243.After lower skid 218 has been properly positioned along lower skid rail 212, upper skid 222 is activated to transversely position drill works 11 within well 243 to locate hole 52 over the desired position (not shown) on bottom 24. Referring to Figure 17, after drilling is completed and the wells are also completed, the drilling equipment 11 may be removed. The rig, such as rig 3, because of its lightweight, openwork body lowering construction cost, may then be economically converted to a production platform. Modules such as crew quarters 400, generators 402, machinery 404, and mud pits and machinery 406 may be loaded on truss member 202 (Figure 17) by drilling equipment 11 as described in Embodiment 3 or by an external crane (not shown). These and additional modules 408 may also be suspended from truss member 202 (Figure 18). The drilling equipment 11 may be removed, if required, either prior to or after the mounting of the modules. Preload tanks 20 may be used for storage of fuel oil and drilling water. Referring to Figures 19 and 20, modules may also be used to provide the necessary facilities to permit jack-up rigs having openwork bodies to be self sufficient, requiring no tender assistance. As best seen in Figure 19, rig 416 is a triangular shaped, slot rig using a superstructure similar to a combination of that of Embodiments 1 and 3. Rig 416 is also provided with leg structure 4 and, additionally, reinforced slot structure 206 forming well 243 such as that of Embodiment 3. A skid system 10 is also provided such as that of Embodiment 3.Superstructure 3 includes support modules to provide all necessary support for drilling operations such as quarters 400, generators 402, machinery 404, mud module 406 including mud pumps 412 and mud pit 413, cranes (not shown) on crane pedestals 409, pressure tanks 410, cement unit 414, shale shaker degasser and desilter and desander 418, and heliport 420. Fuel oil and drill water may be stored in preload tanks 20, if necessary. As best seen in Figure 20, rig 422 is a cantilever type rig using a superstructure similar to that of Embodiment 2. Rig 422 is also provided with leg structure 4 including a base 208 such as that of Embodiment 3. Additionally, rig 422 includes a cantilever beam 112 such as that of Embodiment 2 and an upper skid system 222 such as that of Embodiment 3. The mud pump and mud pit module 406 is located below the pipe rack and in the superstructure, resting on structural members 424. Although the system described in detail supra has been found to be most satisfactory and preferred, many variations in structure and method are possible. For example, the legs can be of any shape including round, three chord triangular, or four chord square legs of either solid or truss structure. The rig may be square or rectangular in plan with four leg segments used instead of three. During transportation, the rig may be dismantled and carried on the deck of a tender or transportation vessel so that it can be transported through narrow channels or rivers. Any type of transportation vessel such as a ship, barge, or semisubmersible may be used. Additional machinery may be located on the floor 50 of the rig to minimize or eliminate tender assistance. Box beams may be used instead of truss structure. Either spud cans or bases may be used with any of the rigs.The platform can be mounted so that it does not revolve about the centre of the circular skid rail 30. The rig may be used to support cranes, quarters, or other apparatus in addition to or instead of the drill works. All of the equipment located on floor 50 may be transported separately on the same or a different vessel. The skid rails may be of any curved shape. The above are exemplary of the possible changes or variations. WHAT WE CLAIM IS:

1. A rig for use in supporting and using equipment above the ocean bottom, comprising: a body, said body being formed by a substantially completely open network of truss-like members, said members forming open inner and outer vertical and horizontal peripheries of said body which permit wind and light to pass

through said body; leg means connected to said body for supporting said body above such ocean bottom while such equipment is in use; platform means mounted on said body for supporting at least some of such equipment; said leg means including elevation means for elevating said body above such ocean bottom and connection means for connecting said elevation means to said body; said body having structural negative buoyancy; and said leg means includes only three legs.

2. A rig as claimed in claim 1, in combination with: a semisubmersible tender vessel adapted for transporting said rig, and for housing some of such equipment separately from said platform means; and connection means for connecting said semisubmersible tender vessel to said body of the rig.

3. A combination of a rig as claimed in claim 1, and having said legs spaced apart a sufficient distance to permit passage of a transportation vessel therebetween and said transportation vessel; including a hull; support means for holding and supporting said body, said leg means, and said platform means on said hull; and shock mount means for dampening and absorbing forces in said support means by compression shock absorption.

4. A combination as claimed in claim 3, wherein each said leg means includes a preload tank having first connection means thereon, and said support means includes second connection means thereon for each said leg means, said first and second connection means being for connecting and holding said preload tanks to said support means.

5. A combination as claimed in claim 4, wherein each said second connection means includes beam means having a base and beam pivotally mounted thereto for engaging a respective one of said preload tank.

6. A combination as claimed in claim 5, wherein each said first connection means includes a socket with an opening therethrough and a set of pulleys; each said second connection means includes a guideline having two ends, and tensioning means for anchoring said first end of said guideline and for placing said guideline under tension; and its beam means further includes socket engagement means for engaging said beam means to said socket of the respective first connection means and for anchoring said second end of said guideline; said guideline being threaded through said opening and on said set of pulleys.

7. A combination as claimed in claim 5 or 6, wherein said support means includes for each said second connection means a support bar pivotally connected at one end to said beam; and hull anchoring means pivotally supporting the other end of said support bar against said hull; and said shock mount means includes a shock absorber mounted on said support bar, resilient means mounted between said beam and said base for damping forces applied to said beam; and base movement means for permitting said base to move in response to forces applied to said beam.

8. A combination as claimed in claim 7, wherein said base movement means includes: a skid rail; and skid means for supporting said base on said skid rail and for moving said base along said skid rail.

9. A combination as claimed in any one of claims 1 to 3, wherein said platform means includes: a curved skid rail mounted on said body, a platform, and skid means mounted on said platform for engaging said curved skid rail and for moving said platform on said curved skid rail.

10. A combination as claimed in claim 9, wherein said curved skid rail is a circular skid rail.

11. A combination as claimed in claim 10, wherein said truss-like members have structural supporting members, and said circular skid rail crosses the boundary of said body substantially at the location of one of said structural supporting members.

12. A combination as claimed in claim 10 or 11, wherein said skid means rotates about the centre of said circular skid rail.

13. A combination as claimed in claim 12, wherein said skid means includes: lower skid means for engaging said circular skid rail and for moving along said circular skid rail; parallel skid rails mounted on said lower skid means; and upper skid means mounted on said platform for engaging said parallel skid rails and for moving said platform on said parallel skid rails.

14. A combination as claimed in claim 13, wherein said parallel skid rails are of sufficient length to permit said upper skid means to move said platform outside the circumference of said circular skid rail.

15. A combination as claimed in claim 13 or 14, wherein said equipment includes a derrick supported at base points by said platform means; said base points being located substantially over said upper skid means.

16. A combination as claimed in claim 1, wherein there is further included in combination a floating ship located on the surface of the water having means for securing said leg means in the ocean bottom.

17. A combination as claimed in any one of claims 1 to 3, 9 to 15 or 16, wherein a respective preload tank connects each said leg to said body.

18. A combination as claimed in any one of claims 1 to 16, wherein said body includes supporting means for supporting some of said equipment on the upper surface of said body separate from said platform means.

19. A combination as claimed in claim 18, wherein said body includes first means and said platform means includes second means for placing such equipment on said supporting means.

20. A combination as claimed in claim 3, wherein said support means includes connection means for connecting and holding said leg means to said transportation vessel.

21. A combination as claimed in claim 20, wherein said connection means includes beam means having a base and a beam pivotally mounted thereto for engaging said leg means.

22. A combination as claimed in claim 20 or 21, wherein said leg means includes holding means and wherein said support means includes a base for each said holding means and said bases include means for relative positioning of said bases with respect to each other to conform to the spacing between said holding means.

23. A rig substantially as described with reference to and as illustrated by any one of the embodiments shown in the accompanying drawings.