US2927436A - Method of operating an elevated deck drill barge - Google Patents

Description

March 8, 1960 c. P. BESSE 2,927,436

ME HOD OF OPERATING AN ELEVATED DECK DRILL BARGE Filed April 23, 1954 5 Sheets-Sheet 1 INVENTOR CELEST/NE P UL BESSE BYM c. P. BESSE 2,927,436

5 Sheets-Sheet 2 ATTO RN K/&

CELEST/NE PA L BESSE March 8, 1960 METHOD OF OPERATING AN ELEVATED DECK DRILL BARGE Filed April 23, 1954 March 8, 1960 c. P. BESSE 2,927,436

METHOD OF OPERATING AN ELEVATED DECK DRILL BARGE INVENIOR CELEST/NE PAUL BESSE 2,927,436 METHOD OF OPERATING AN ELEVATED DECK DRILL BARGE Filed April 23, 1954 c. P. BESSE March 8, 1960 5 Sheets-Sheet 4 QOE INVENTOR CELEST/NEP L BESSE C. P. BESSE March 8, 1960 METHOD OF OPERATING AN ELEVATED DECK DRILL BARGE Filed April 23, 1954 5 Sheets-Sheet 5 INVENTOR CELEST/N P LBESSE I TTORS United States P o a METHOD OF OPERATING AN- ELEVATED DECK-DRILL BARGE Celestine- Pauli Besse, New Orleans, Ila ,v assignor, by

mesne assignments, to California Research Corporation; San Francisco, Califl, a corporationof'Delaware' Application Apt-i123, 1954, Serial Not 425,162 sciaims. (C1; 61-46;5).

'I-he present'invention relates to methods of and apparatusforestablishing submersible foundations for drilling rigs, more particularly to a methodlof operating bargeshaving elevated drilling decks whichare adaptedto bepositioned' above a body of water, upon whose bottomthe-bargehull-is to be'landed, and has for an object the prov-ision-of-amethod of establishing a submersible foun dationadapted to: be maintained stable throughout the establishment thereof at anunderwaterlocation, as well as' during the subsequent raising: of the foundatiomwhichincludesthe stepsof providing-buoyant pontoon means, which may? be hydraulically operated, adapted to extend fronr the barge hull to the underwater. bottom, stabilizingthe pontoon means* on bottom" by applying; hydraulic fluid tojthe cylinders-,- but withsaid-hull being maintained in a floating condition until said pontoon means are firmly seated on bottom, and then submerging the barge hull by the flooding thereof, thereby to cause retraction: of the pontoon means into engagement with the barge hull on bottom.

Various forms of submersible foundations have been roposed: heretofore for drilling through relatively shal- 10w" bodies of water,-that is, at depths of about 1'0 to 30 feet. Among those forms of previously known foundations are those employing an elevated deck adapted to be positioned above the water surface and extend on colurnns through-- the body of water above a submerged hull resting on bottom. This type of drilling foundation has presented serious problems in maintaining stability of the hull during submersion andsubsequent raising of the hull. One form of structureof this type has been known as the one-end-first type submersible-barge. This barge arrangement presents grave difi'iculties' inmaintaining sta-' Eilit'y, due to the necessary tipping of the elevated drill deck during the submersion of the hull, which touches one end on bottom to serve as a stabilizing element while lowering the other end of the barge. v x Other means which have been used heretofore for the landing of barges having elevated drill decks on bottom have employed pontoon members which have remained a floating condition adjacent the sides of the floating hull during the submersion operation. The primary diificulty with this type of construction is that the ponteons require considerable space adjacent the sides of the barge. An additional difficulty in operating this latter type of structure is the lack of stability during s'ubinen use and raising of the hull. 4

In accordance with the present invention, there is rovided a method and apparatus for establishing a submersible foundation for a drilling rig which contemplates the floating of a submersible hull to a drilling location, said hull including pontoon means positioned directly belowthe floating hulladapted to be extended and retracted through hydraulic ram means positioned within aplurality of supporting columns upon which the elevated deck is mounted above the submersible hull. Fur- ,ther, inaccordance with the invention, the bouyant pontoon means form a spread fodting for" the hydraulic CO1- 2,927,436 Patented. Man. 8,,196Q

ICE

umns which may be extended to the land'bjottom while; the pontoon means are maintainedin a buoyantlcondition. With said buoyant pontoon meanspositioned' on; bottom, the stability of the structure may be further: increased by the application thereto of at, least a portiQmofI the weight of the barge through hydraulic ram meansadapted to lift the barge hull above its. normal floating; position,.without decrease. in the buoyancy ofthehull; itself, thereby. assuring a firm foundation for the. hull" prior to submergence. to bottom. Following thelanding, of the buoyant pontoon means and. increasing the stability; of. those means on. bottom, the hull may. be submerged; at a desired rate by, decreasingrthe buoyancy of. theh lll. andv simultaneously controlling; the lowering of the hull, into. engagement-with the pontoon member by removing,

the. hydraulic fluid. from. the hydraulic rammeans.

In accordance with another aspect of the present invena tion, there isprovided amethod of raising thesubmerse ible hullconstructed in accordance with the invention, from-landv bottom to' the water surface, which includes. thestepsofmaintaining the pontoon means in abuoyant condition and exerting through the hydraulic ram means: sufficient: lifting force to raisethehull above the buoyant pontoon means-when the hull contains suiiicient. ballast; to be non-buoyant. Under these conditions, the-hull may be-raised at adesiredrate to a position with-thehullsdeclt; above the waters surface, andthen the buoyancy of the: hullincreaseduntil-the hull is again floating freely: anthe; waters surface.- Following this operation, the hydraulic; ram means may be operatedto retract the buoyant porn toon' members into. engagement with the bottom; of, the; submersible hullgand the foundation prepared for-floating; to anotherdrilling location;

In a preferred. form. of apparatus for carrying out; the, method;v of the. present invention, the buoyant pontoon members are desirably-nested adjacent; the four corners, of the submersible barge hull, so, that the pontoon mcnrbersare retracted: within the over-all outlines of the barge;- hull; both: during. the operation of floating the dril, -g; barge to an underwater; location, an d during the time the hull; is submerged onland-bottom at the drilling location.

Further objectsand advantages of the present inverter tion will: become. apparent from the following detailedi description taken. in conjunction with the, accompanying drawings which form anintegral part. of the present: specification.

In the drawings:

Fig. I isa top plan view of the elevated deck of a drilt barge constructed. in accordance with the present invert-r tion, particularlyillustrating one arrangement of the rela-. tive positionsof the buoy-ant pontoon members and" the; hydraulic ram members used in extending and retracting the buoyant pontoon members relative to the barge huh.

Fig. 2 is a front elevation view of the barge illustrated in Fig. 1, showing the pontoon members in their nested position along the side of the barge hull when said barge is being towed to location.

Fig. 3 is a view similar to view 2, particularly illus:v hating the manner in which the pontoon members are adapted to'be extended from their nested position by the hydraulic ram means into engagement with bottom at a drilling site.

Fig. 4 is a view similar to Figs. 2 and 3, illustrating, the position of the pontoons during increase of stability of the barge hull thereon by decreasing the draft of the barge hull to apply at least a portion of the weight thereo't to the buoyant pontoon members. I

Fig. 5 illustrates the final position of the buoyant pon toon members and the submersible hull with the foundat-v tion in its drilling position on bottom and the elevated drill deck above the water surface.

Fig. 6 is a side elevation view of the submersible "nearse foundation barge illustrated in Fig. 1, showing the pontoon means in extended position.

Fig. 7 is a detailed view in sectional elevation of the hydraulic ram means employed in extending and retracting the buoyant pontoon members.

Referring now to the drawings, and in particular to Figs. 1 and 2 through 5, inclusive, there is illustrated a submerslble foundation of the elevated drill deck type particularly adapted to carry out the method of the present invention. As shown in Fig. 1, the drill barge provides support for a drilling platform 11 upon which derrick 12, whose corner posts 13 are indicated in the drawing, may be erected. The drilling machinery, including draw works 14, power generating equipment 15, drilling fluid tanks 50, pumps 51, and the like, are adapted to be supported above the waters surface at. an underwater drilling location. On elevated deck drill barge 10, drill deck 11 is supported in its elevated position by a plurality of tubular columns 16 having positioned therein hydraulic ram means indicated generally as 17. As indicated in Fig. 5, columns 16 are adapted to position drill deck '11 at a. sufl'icient distance above submersible hull 18 so that the hull may he landed on water bottom while drill deck 11 remains above water. This distance between deck 11 and hull 18 may, of course, be varied to satisfy the depths in which drilling is to be done.

As mentioned hereinabove, the submersible hull 18 has positioned therebelow pontoon members 20, which in the present instance comprise four buoyant tank members nested adjacent the four corners of the submersible barge hull 18. These submersible pontoon members 20 are connected to hull 18 through piston elements 21 which form the piston members of hydraulic ram means 17. "As particularly illustrated in Fig. 2, the entire drill barge assembly is adapted to be floated to a desired drillnig location below a body of water, with the pontoon members 20 in their retracted and nested position around the corners of barge hull 18. When the drilling barge assembly has been located at the desired position, the hydraulic ram means 17 are brought into operation by the application of hydraulic pressure to force piston means 21 downwardly through the column 16 to force pontoon means 20 into engagement with land bottom. This operation is particularly illustrated in Fig. 3.

. After pontoon membersZt have been spotted on bottom to establish the location of the barge at the desired location, the draft of the barge hull 18 may be decreased so that the barge is raised above its normal floating position and into a position such as that illustrated in Fig. 4. In this way, the loading on the spread footings, formed by the pontoon members 20, may be increased without adding ballast to the barge hull itself, so that there is minimized the danger of the barge tipping and possibly upsetting during the landing operation. Accordingly, after the full load, or a substantial portion thereof, has been applied to the foundation pontoons, the buoyancy of the barge hull 18 may be decreased so that the barge may be sunk to land bottom as illustrated in Fig. 5. Further in accordance with the invention, this submergence of hull 1 8 is fully controlled by ram means 17 so that the barge will be gently and evenly lowered to bottom. As shown in Fig. 5, with hull 18 on bottom, the pontoons 26 again nest within the corners of the barge hull 18, as they did when the barge was in a floating condition.

As contemplated in a preferred manner of carrying out the present invention, the pontoon members 20 are maintained buoyant throughout the time that the barge hull rests on bottom, that is, throughout the time that the Well is being drilled from the elevated deck 10. Following completion of drilling in a desired location, it is desirable to be able to raise the barge hull 18 to its full floating position preparatory to moving to another location. In

under consideration, the suction created between underwater bottom and the lower portion of barge hull 18" may be so great that it is necessary to add auxiliary raising pontoons to the structure, or employ jet streams to extricate the hull from bottom. Under these conditions, with the barge hull at its normal buoyancy for floating conditions and still remaining on bottom, the barge hull,

, the elevated deck, and the associated drilling equipment may pop" to the surface, as would a cork held at the bottom of a body of water and then suddenly released,

Obviously, the instability of such an operation leaves much to be desired in the safety of the structure and the operating personnel.

In accordance with the present invention, the foregoing difliculties in raising the submerged hull 18 are alleviated to a great extent by operation of the hydraulic ram means 17, which are capable of raising the barge hull l8 and the elevated deck on the spread foundation on poptoon members 20 to a floatable position while the barge hull is maintained with substantially the same negative buoyancy as when it is lying on bottom. Accordingly, the barge hull may be raised to substantially its full floating position, or to any desirable intermediate level before the water or ballast is removed from the barge hull. Thus, the entire structure may be stabilized uponl buoyant pontoon members 20 during the raising opera- In this manner, the structure is held substantially tion. stable at all times, throughout both the raising and lowering operation, without danger of tipping of the structure during either raising or lowering of the barge hull.

While the buoyant pontoon members 20 have been illustrated as being positioned in the respective corners,

and lying along the longitudinal length of the barge hull.

18 as particularly shown in Figs. 1 and 6, it will be apparent that the method of the present invention may be applied to any desired type of buoyant pontoon means, including one which extends over the entire lower surface of the barge hull 18. Likewise, the degree of,

7 buoyancy of the pontoon means may be adjusted to a desired degree for the type of underwater foundationbed encountered at the drilling site. The two foundation pontoons 20 lying along the port side may be joined together as one elongatedpontoon member, and those along the starboard side may be similarly linked together.

Referring now particularly to Fig. 7, there is, illustrated a sectional, elevation view of the hydraulic ram means 17 constructed in accordance with the present invention.

As therein shown, the hydraulic ram means 17 preferably previously-known structures, this operation has been percomprises an outer circular column 16 forming the cylinder ram means 17. In practice, this column may be a section of pipe of suflicient strength and rigidity to support, as a structural column, the elevated machinery deck 10 as a stable structure a predeterminable distance above the top of the barge hull 18. As illustrated in Fig. 7, column 16 may be welded adjacent its lower end to the bottom and top of barge hull 18 and extends above ma chinery deck 11 to a cylinder head, designated generally as 35. Directly below the cylinder head 35 there is provided hydraulic fluid conduit means 36. adapted to supply or withdraw hydraulic operating fl id to the hydraulic ram means 17. The hydraulic fluid operating on piston member 21, which may be formed as a piston bythe addition of a head 38 to pipe member 39, serves to move the piston and pontoon relative to hull 18. Piston 21 is provided with suitable packing means. including O-ring .40, to hold the hydraulic fluid in the cylinder head. To the lower end of pipe 39, forming the skirt portion of the ram element 21, the buoyant pontoon member 20 is attached by welding the lower and upper portions of the pontoon to the bottom of the skirt portion of pipe '39. .It will be noted that the top of piston means 21 is secured to the lower portion by eye bolt 41. This bolt permits ready withdrawal of head 38 from the ram.

, While not iliustrated in detail, it will. of course, be understood that the barge hull 18.desirably will be conipa tn ented so that the load on the hydraulic ram means 17 may be suitably distributed during the raising and lowering of the buoyant pontoon means relative to the barge hull. Likewise, barge hull 318, as indicated in Fig. 1, is suitably provided with a so-called "T-slot 25 formed longitudinally in the barge'hull. Slot 225 permits access to the underwater bottom for the drill pipe through the center of the barge, and after drilling of a well, permits the hull to be moved away from the well, while the Christmas tree and other production facilities are left standing above the water.

While various modifications and changes, both in the method of operating the submersible barge, constructed in accordance with the present invention, as well as in the form of the barge which may be used to perform the method of the present invention, may be made without departing from the invention, all such modifications and changes which come within the scope of the appended method and apparatus claims are intended to be embraced thereby.

I claim: j

1. A method of raising a submersible foundation hull for a drilling rig from contact with a land bottom underlying a body of water through said body of water to the surface thereof, in which said foundation hull has positioned beneath it buoyant pontoon spread footings for columns telescopically connected to said foundation hull and actuated by power means on said drilling rig to be extended and retracted relative to said foundation hull, and in which the stability of said drilling rig during the raising operation is maintained by keeping the foundation hull in a negatively buoyant condition while a thrust is exerted on said buoyant pontoon spread footings through said columns by said power means to lift said foundation hull from said land bottom until said foundation hull is in substantially a floating position at the surface of the water, and in which ballast is then removed from said foundation hull to float said foundation hull independently of the support of said buoyant pontoon spread footings, and in which said buoyant pontoon spread footings are then retracted from engagement with said land bottom through said telescopically connected columns.

2. The method of constructing a submerged foundation for an offshore drilling rig which has a drilling deck supported above the surface of the water by structural members connecting the drilling deck with the submerged foundation which comprises the steps of positioning beneath a submersible unitary foundation hull buoyant pontoon means which have a horizontally disposed bottom" said columns downwardly, increasing the loading on said buoyant pontoon means by decreasing the buoyancy for at least a portion of the weight of said foundation hull while supporting said foundation hull at substantially its initial floating position by said columns and said power means to increase the stability of said pontoon means on the land underlying the body of water, and then decreasing the buoyancy of said foundation hull to lower said foundation hull along said columns under the control of said power means and into engagement with the surface of the land underlying the body of water to position said foundation hull on said land to support the weight of the drilling rig.

3. The method of controlling the submersion of a submersible foundation hull for a mobile drilling rig adapted to drill through a body of water, wherein said hull is adapted to support drilling apparatus on an elevated deck supported vertically above said hull on a plurality of support columns and has a plurality of buoyant pontoon spread footings positioned along opposite sides thereof below and in substantially vertical alignment with said support columns, said buoyant pontoon spread footings are operatively connected to said support columns by respective second columns telescoped within said support columns, and said second columns are extendable out of and retractable into said support columns under the influence of connecting power means between said support columns and said second columns, which method comprises submerging said buoyant pontoon spread footings into engagement with the surface of the land underlying said body of water at said drilling location by extending said second columns out of said support columns by said power means, actuating said power'means to further extend said second columns out of said support columns to apply at least a portion of the weight of said submersible hull to said buoyant pontoon spread footings, said buoyant pontoon spread footings having an extended horizontally disposed surface to prevent substantial penetration of the bottom portion of said second columns into the earth of the submerged surface of the land, increasing the weight of said submersible hull by flooding to decrease the buoyancy thereof, operating said power means to retract said second columns into said support columns to lower said submersible hull into engagement with said surface of the land while maintaining control over the lowering of said submersible hull by said power means, and supporting said drilling deck and drilling apparatus on the submerged hull during a drilling operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,217,879 Willey Oct. 15, 1940 2,248,051 Armstrong July 8, 1941 2,327,118 MacKnight Aug. 17, 1943 2,334,992 Crake Nov. 23, 1943 2,540,878 Hayward Feb. 6, 1951 2,603,068 Wilson July 15, 1952 2,657,540 Templeton Nov. 3, 1953 2,771,747 Rechtin Nov. 27, 1956

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