US2248051A - Offshore drilling rig - Google Patents

Description

July 8, 1941.

W/T/VESS:

E. R. ARMSTRONG 2,248,051

OFFSHORE DRILLINGRIG 5 sheets-sheet 1 Filed Dec. 28, 1958 9m 7%. a 1M5 2M J l 5 LIN B e e wPl 2, w 2 m M s a 5 W G $8 L2 SI. ll M MW I RED Amm EM M 0 1L w W 8 ..W h

y 1941. E. R. ARMSTRONG 2,248,051

OFFSHORE DRILLING RIG Filed D66. 28, 1938 5 Sheets-Sheet 3 y 1941- E. R. ARMSTRONG 2,248,051

OFFSHORE DRILLING RIG Filed Dec. 28, 1938 5 Sheets-Sheet 4 W/T/VESS.

Patented July 8, 1941 UNITED STATES PATENT OFFICE OFFSHORE DRILLING an;

Edward R. Armstrong, New York, N. 1., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application December 28, 1938, Serial No. 248,051

11 Claims.

The present invention relates to an apparatus for drilling oil wells oii shore, and particularly to an apparatus which may readily be transported from place to place and placed in position for drilling.

It has heretofore been proposed, when drilling in shallow inland waters, to provide a barge having a superstructure thereon capable of supporting the full load of the drilling equipment, to tow such barge to the location at which the well is to be drilled, and, by flooding the barge, sink it this purpose.

to position on the bottom so that a deck on the superstructure upon which drilling equipmentis mounted remains above the water line. Such a structure is shown in the Giliasso Patent No. 1,681,533, issued. August 21, 1928.

It is readily discernable that such a structure has its limitations in that the drilling equipment must be very evenly distributed over the deck in order that the barge may be sunk to the bottom without tilting or capsizing. In practice it has been impracticable to provide a structure which is capable of holding a drilling rig and the necessary power supply means whether such power supply means he steam boilers or Diesel generator sets. It is also apparent that the depth of water in which a well may be drilled with such and other weather conditions.

It is also the further object of this invention to provide a structure which may readily be used with the heaviest of drilling equipment and the tallest of derricks in order to provide a floating yet stable structure capable of drilling wells of between 10,000 to 15,000 feet in depth. In accordance with the present invention, a plurality of circular pontoons are provided, each pontoon preferably being provided with a circular aperture through which a spud or column having an enlarged bottom extends. The enlarged bottom of the spud or column extends up into the pontoon so as to be flush with the bottom surface thereof, providing a structure which may be readily towed through shallow waters. These spuds or columns may be lowered or raised relative to the pontoons by varying the buoyancy of each spud column by pumping in or out the necessary water to give each spud column the buoyancy desired. When the relative position or each spud column in its pontoon is that desired, and obtained by buoyancy control of the spud column as outlined, each can be locked in position by suitable looking or clamping devices provided for Thus, when it is desired to operate the drilling rig to drill awell, the water is admitted to each of the spud columns so that they sink until they come firmly to rest on the ocean bed. They are thenlocked in this position and controlled amounts of water then admitted to the main pontoon system thereby reducing its buoyancy and increasing weight supported by the spud columns to that desired thereby causing them to provide a firm foundation for the structure. The pontoon system is held together by a truss system on which is built the drilling structure consisting of two or more decks carrying drilling and power equipment anda drilling derrick.

It is an object of the present invention to provide a floating structure capable of being partially supported by spuds or columns extending to the bottom of the water in which the structure is being used. 7

It is also an object of the present invention to provide a structure composed of a plurality of pontoons held together in' a unitary structure by a truss system on which 'is supported complete drilling and power equipment 101* drilling wells from two to three miles in depth.

It is also an object of the present invention to provide a structure which may be readily refloated and removed to another location after the completion of a well.

In order that a better understanding of the invention may behad, reference, is made to the accompanying drawings in which:

Fig. 1 is an outboard profile of the structure in towing condition;

Fig. 2 is alongitudinal section taken through Fig. 1 and showing the structure in position for drilling in shallow. water;

Fig. 3 is a transverse section through line 3-3 of Fig. l-showing the same structure in position for drilling in deep water;

Fig. 4 is a section taken on line 4-4 of Fig. 1 showing the top only of the upper buoyancy tanks and the deck trusses.

Fig. 5 is a section taken on line 5-5 of Fig. 1 showing the top of the lower buoyancy tanks and the struts for holding the same in one unitary structure.

Fig. 6 is a plan view of the upper deck; and

Fig. '7 is .a plan view of the lower deck.

Referring now to the drawings, It] indicates the main or lower buoyancy tanks which in the em bodiment illustrated are eight in number, and which have circular recesses H therein arranged to accommodate the enlarged bottoms l2 of the spuds or columns l3. The lower edges of the bottoms l2 are relatively sharp and capable of penetrating into the sea bottom. Avalve 40, which may be operated from the top of the column is provided in or near the bottom of each of the spuds l2 for admitting or removing water thereto, while a valved line 4i communicates with the interior of each of the columns near the top thereof for venting air therefrom or admitting compressed air into the column to control the height of water therein and thus control their buoyancy. By referenceto Fig. it will be noted that the recesses ll are eccentric to the circular pontoons or tanks in and are placed as near to the outside of the unitary structure as possible. Locking means are provided for locking the columns l3 in raised or lowered position. The pontoons or tanks H) are joined together by diagonal struts l4 and by longitudinal and transverse struts l5 and IS. The two central longitudinal struts l1 and diagonal struts l8 are arranged to be readily removed in order topermit the structure to be floated away from the well after the same has been completed.

Immediately above the buoyancy tanks ill are placed the upper buoyancy tanks l3 which are securely fixed, as by welding, to the buoyancy tanks ill, the upper tanks l9 being provided with circular passages therethrough for the accom,

modation of the spudsor columns l3. Each of the tanks I9 is provided with asuitable locking device 20 for securely clamping the column in any desired position. The upper buoyancy tanks carry atruss system 2|, which, together with the strut system I 5, I6, I! and I8 joins the structure so as to provide a solid structure for the drilling equipment, power supply, etc., whether the structure is in its entirely buoyant position or is partially supported by the spuds I3 resting on the bottom. 7

On thetruss system 2| there is supported alower deck 22 and anupper deck 23. Between the four central upper buoyancy tanks I 9 and the lower deck are provided twotanks 24 and 25 which are partitioned to provide in all four tanks, one of which is used as the active mud pit, another as the reserve mud pit, the third as a fresh water storage tank and the fourth as a fuel oil storage tank. On thelower'deck there is placed the power equipment 26 (Fig. 7) consisting, for example, of a Diesel electric plant and the various pumps and compressors necessary to the drilling operations. 'On the top deck is supported aderrick 21, together with the draw works 28 for a drill operating through casing as well as twoderricks 23 and 30 for transporting material above the structure or lifting it from a service boat on to the structure.

The necessary auxiliary drilling equipment and service facilities may be distributed about theupper deck 23 andlower deck 22 of the superstructure, a suggestive arrangement being diagrammatically illustrated in Figs. 6 and 7. Thus, in addition to the draw works 28, acoring reel to thepower plant 25, may be placedslush pumps 35,aircompressor 36,mud mixer 31 andshale shaker 33. Any other necessary or desirable equipment may be placed on the decks. In arranging the equipment on the decks, it is desirable that the load be distributed as evenly as possible in order to trim the apparatus. However, in case of eccentric loading, it is possible to admit water to certain of the buoyancy tanks and thereby cause the apparatus to float on an even keel.

The operation of the apparatus is as follows:

The entire apparatus with the columns l3 raised so that the spuds i2 are within the floats I0 is towed to the site of the drilling operation. Assuming that the drilling rig is floating level at its proper draft, the columns l3 are unlocked by releasing thelocking devices 20 and water is gradually admitted to each of the spud columns so that they sink until the enlarged bottoms or in the bed or floor of the ocean as far as they will go and the columns I3 are then locked in their lowered position by means of themechanical locking devices 20. A controlled amount of water is then admitted to the lower buoyancy tanks l0 thereby lessening their buoyancy and increasing the weight supported by the columns l3 to that desired and driving the spuds l2 firmly into the floor of the ocean. Suflicient water is admitted to the lower buoyancy tanks ill to firmly anchor the apparatus and to cause the columns l3 to provide a firm foundation for the structure. As the apparatus settles in the water, theupper buoyancy tanks l9 are partially submerged so that they support a portion of the weight of the apparatus by their displacement of water while the columns I3 support only the difference between the total weight of the apparatus and the effective buoyancy.

Once the apparatus has been positioned at the site chosen for drilling, the regular drilling equipment is operated in the manner customary when operating on land and the well is drilled in the usual manner, the necessary supplies and equipment being transported to the apparatus by service boats and being used in the usual manner. At the completion of the drilling at the given site, piles may be drivenfrom the decks of the apparatus and a suitable structure erected on the piles for supporting any necessary surface equipment such as the customary Christmas trees for controlling the wellswhen flowing, and means, such as pipe lines, on the floor of the ocean, may be provided for handling the oil. All connections between the derrick and the well may then be severed and the well connected to the usual surface connections provided on the pile or other foundation which has been built. The entire apparatus may then be refioated by forcing water out of the lower buoyancy tanks or pontoons l0, thereby increasing their buoyancy and causing them to support the entire weight of the apparatus, taking any load Off the columns or spuds l3 and raising the spud shoes it from the bed of the ocean. The spuds or columns l3 may then be raised by forcing the water out of them either by pumping or by means or compressed air, thereby causing them to be raised by their buoyancy so that the shoes or bottoms l2 thereof enter the recesses provided therefor in the pontoons in after which the columns may be locked in their raised position by lockingdevice 20. The apparatus may then be towed to another drilling site.

From the above description, it is apparent that; I have provided an apparatus which may be floated into position over a proposed under water drilling site. The apparatus may be firmly anchored to the bottom and is not affected by the action of waves. Furthermore, the apparatus provides a self-contained drilling structure with ample room for all necessary equipment and activity connected with oil well drilling and with ample space for the storage of reserve supplies or equipment.

No attempt has been made in the specification to describe the drilling apparatus per se in detail, since it is contemplated that the customary drilling apparatus will be used. Likewise, the arrangement of the necessary drilling and aukiliary equipment on the decks of the apparatus illustrated in Figs. 6 and 7 is merely suggestive and not limiting and any suitable arrangement may be used. Various other modifications may be made in the design of the apparatus without departing from the spirit of my invention or the scope of the appended claims.

What I claim and desire to protect by Letters Patent is:

1. An offshore drilling rig comprising a superstructure adapted to support a derrick structure,

a plurality of horizontally spaced independent buoyancy units connected in spaced relation to said superstructure and supporting the same, means for regulating the buoyancy of said units, a plurality of longitudinally movable vertical columns supported by said superstructure and means for locking said columns in a vertically adjusted position in extension below the buoyancy units respectively. 7

2. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced independent buoyancy units connected in spaced relation to said superstructure and supporting the same, each of said buoyancy units comprising a lower enlarged closed pontoon of relatively large horizontal cross-section and an upper closed buoy-- ancy tank of relatively smaller horizontal cross section than said pontoon, said pontoons having sufficient buoyancy for supporting the entire apparatus, a plurality of longitudinally movable vertical columns supported by said superstructure and means for locking said columns in a vertically adjusted position in extension below the buoyancy units respectively.

3. An offshore drilling rig comprising a superstructure adapted to support a derrick structure,

a plurality of horizontally spaced buoyancy units connected to and supporting said superstructure,.

each of said buoyancy units comprising an'annular closed tank, a vertical column extending through an opening in each of said buoyancy units and movable longitudinally therethrough and means for locking said columns with respect to said buoyancy units.

4. An oifshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced buoyancy units connected to and supporting said superstructure, each of said buoyancy units comprising a lower annular closed tank of relatively large horizontal cross section, said tanks having suflicient buoyancy to support the entire apparatus and an upper annular closed tank of relatively small horizontal cross section, means for admitting water to said lower tanks, a vertical column extending through an opening in each of said buoyancy units and movable longitudinally therethrough and means for locking said columns in position.

5. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced buoyancy units connected to and supporting said superstructure, each of said buoyancy units comprising a lower annular closed tank of relatively large horizontal cross section, said tanks having suflicient buoyancy to support the entire apparatus and an upper annular closed tank of relatively small horizontal cross section, means for admitting water to said lower tanks, a vertical column extending through an opening located eccentrlcally in each of said buoyancy units and movable longitudinally therethrough and means for locking said columns in position.

6. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced buoyancy units connected to and supporting said superstructure, each of said buoyancy units comprising an annular closed tank, a. vertical column extending through an opening in each'of said buoyancy units and movable longitudinally therethrough, an enlarged bottom on each of said columns, a recess in the bottom of each of said buoyancy units adapted to receive said enlarged bottom of said columns, and means for locking said columns in position.

7. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced independent buoyancy units connected in spaced relation to said superstructure and supporting the same, means for'regulating the buoyancy of said units, a plurality of longitudinally movable vertical columns supported by said superstructure, said columns being adapted to be lowered to engage the bottom to anchor said buoyancy units and means for locking said columns in lowered position.

8. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced buoyancy units connected to and supporting said superstructure, each of said buoyancy units comprising an annular closed tank, a vertical column supported from each of said buoyancy units and movable longitudinally with respect thereto and means for locking said columns with respect to said buoyancy units.

9. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of horizontally spaced independent buoyancy units connected in spaced relation to said superstructure and supporting the same, means for regulating the buoyancy of said units, a longitudinally movable vertical column extending through each of saidbuoyancy units, said columns being adapted to be lowered to engage the bottom to anchor said buoyancy units and means for locking said columns in lowered position.

10. An offshore drilling rig comprising a superstructure adapted to support a derrick structure, a plurality of longitudinally movable vertical columns supported by said superstructure and adapted to engage the bottom of a. body of Water upon which the rig may float, each said column having a water-tight compartment formed interiorly thereof, means for flooding and emptying said compartment to raise or lower said umns supported by said superstructure and "10 adapted to engage the bottom of a body of water upon which the rig may float, each said column having a water-tight compartment formed interiorly thereof, means for flooding and emptying said compartment to raise or lower said column, and means tor locking said columns in a vertically adjusted position in extension below the superstructure.

EDWARD R. ARMSTRONG.

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