US2927435A - Offshore platforms - Google Patents

Description

March 8 1960 M. M. UPSON OFFSHORE PLATFORMS 4 Sheets-Sheet 2 Filed Sept. 23, 1955 Tic. 3.

March 8, 1960 M. UPSON 2,927,435

OFFSHORE PLATFORMS Filed Sept. 23, 1955 4 Sheets-Sheet 3 March 8, 1960 M. M. UPSON 2,927,435

OFFSHORE PLATFORMS Filed Sept. 25, 1955 4 Sheets-Sheet 4 51 N55 A 50 A INVENTOR.

S & g am/E1 L Mqmfiw l/Psa/v ATTORNEYS.

United States Patent OFFSHORE PLATFORMS Maxwell Mayhew Upson, Englewood, N.J., assignor to gZaymond International Inc., a corporation of New ersey Application September 23, 1955, Serial No. 536,202

3 Claims. (Cl. 61-46) g This invention relates to methods and structures for providing foundations at offshore locations such as for supporting oil drilling, storage or other equipment. Among other possible uses, the invention is particularly applicable for use at open sea locations which are subject to heavy wave and wind pressures developed by hurricanes and where the sea bottom is of a relatively soft character.

The type of offshore foundation now generally used for this purpose comprises a large and exceedingly heavy braced frame structure embodying vertical tubes through which vertical piles may be driven down into the ocean floor to support the structure, the frame being stiffened by diagonal braces intended to be of sufficient number and strength to withstand the severe horizontal loads to which the structure is subjected during periods of bad weather and high winds. Such structures are not only very expensive, but as presently used, frequently. weigh several hundred tons and are thus ditficult to install, and almost impossible to remove in case oil production at the location should cease, or in the event that dry holes are encountered.

The present invention provides a simpler and less expensive form of structure which is much easier to install and remove and which for a givenexpense is much more able to withstand severe open sea or offshore weather conditions.

In accordance with the present invention at least one, and-preferably a plurality of vertical piles are first driven in predetermined positions and then a frame having guide portions for slidably receiving the vertical pile or piles is lowered down along same and secured at a substantial "distance down from where the working platform is to be located. Preferably, but not always necessarily, this frame is lowered to a level below the region where wave idisturbances occur. Such frame is provided further with a plurality of guideways positioned at angles to the vertical to serve as guides and holding means for batter piles, that is, piles which are to be, driven at a substantial angle to the vertical. Such batter piles are then driven "through such guideways in positions not only to form braces for widening the base of the structure on the ocean floor, but also to act in effect as diagonal braces of great strength, extending between the upper portions of the vertical piles. The upper portions of the vertical piles as well as the upper end portions of the batter piles are securely afiixed together by another frame which preferably forms the desired platform above the water surface.

Preferably, although not necessarily, the batter piles, as well as the vertical piles if desired, may be in the form of large prestressed tubular concrete units, each driven 'to a considerable depth into the ocean floor and with additional smaller piles driven down therethrough further into the mud and grout bonded with respect to the interior of the hollow concrete piles. In this way, anchor.- age means extending to great depths in the ocean bottom may be obtained, and whereby the batter pile assemblies 2,927,435 Patented Mar. 8, 1960 may act alternatively under tension or compression to resist with great strength the horizontal components of hurricane forces and with the exposure of substantially the minimum possible surface areas to the forces of the wind and waves.

Other and more specific objects, features and advantages of the invention will appear from the detailed description given below, taken in connection with the accompanying drawings which form a part of this specification and illustrate by way of example the present preferred embodiments of the invention.

In the drawings:

Fig. 1 is an elevational view of one embodiment of the invention and showing somewhat schematically an arrangement of pile driving equipment upon the structure for driving the batter piles;

Fig. 2 is a plan view of the structure of Fig. l and showing how the pile driving equipment may be turned to various positions for driving the several batter piles;

Fig. 3 is an elevational view of a somewhat different embodiment of the structure of the invention with an oil drilling derrick structure schematically indicated as mounted thereon;

Figs. 4 and 5 respectively are sectional views taken substantially along lines 4-4 and 5-5 of Fig. 3;

Fig. 6 is a view, partially broken away, showing a portion of another and preferred embodiment;

Figs. 7 and 8 respectively are sectional views taken substantially along lines 7-7 and 88 of Fig. 6;

Fig. 9 is a detailed horizontal sectional view showing considerably enlarged one of the corner portions for example of the frame shown in Fig. 8;

Fig. 10 is a vertical sectional view taken along line 10-10 of Fig. 9;

Fig. 11 is an enlarged horizontal sectional view such as of one of the corner portions of the frame shown in Fig. 7;

Fig. 12 is a vertical sectional view taken substantially along line 1212 of Fig. 11; and

Figs. 13 and 14 are respectively elevational and plan views showing how pluralities of the structural assemblies may be interconnected to form a more extensive platform.

Experience has demonstrated that under the usual conditions prevailing at sea, that is during the occurrence of swells and waves, it is impossible to drive batter piles in desired predetermined positions from floating barges or pile drivers. Thus according to the present invention, in order to drive the batter piles in the desired locations, means are first provided for holding them in place during driving. The preferred method for accomplishing this in accordance with the present invention, involves first driving a single vertical pile as at 15 (Fig. 1), then any suitable guide means may be secured or strapped to this pile for guiding a plurality of other vertical piles as at 16, 17 and 18, while same are being driven at predetermined locations with respect to the first pile. Then a framework as at 20 is dropped over the vertical piles and lowered preferably, although not necessarily, to a position well below the region in the water which will be seriously disturbed by wave motion during storm conditions. This frame 20 may be formed at its corners respectively with apertured portions as at 20a adapted to slidably receive the vertical piles and these corner portions may be interconnected as by horizontal brace means "20b. Such frame is also formed with outstanding arm portions as at 21 at its corners, which support portions as at 22 containing angularly positioned apertures for slidably receiving and guiding the batter piles such as indicated at 23. The frame 20 may be suitably permanently secured at the desired elevation on the vertical piles as by grout bonding the piles with respect to the interior of the sleeve-like portions 20a. Such frame may he made of steel, reinforced concrete or other materials, and after it has been lowered and secure inplace, then a permanent second framework 24 is placed on top of the piles 18 inclusive and suitably secured thereon, this second frameworkforming a platform whieh also has guides as at 25 with angularly positioned apertures for slidably receiving and guiding the batter piles which now may be driven by equipment mounted on the platform 24.

Thus as shown in Figs. 1 and 2, pile driving apparatus as schematically indicated at 26 may be provided with lead or guide structure as at 27 for the driving hammer 28 positioned at an angle corresponding to the desired angle of the batter piles. This pile driving apparatus may be mounted in suitable known Ways so that its position can be adjusted to bring the hammer into alignment successively with the desired position of the axisof each of the batter piles for driving the latter while they are being guided by guides as at 22 and 25 at the desired predetermined angles to the vertical. That is, in Fig. 2, the base 26' for the pile driving apparatus is shown in full lines at a position for driving a batter pile at the lower left hand corner of said figure, whereas the position of the pile driving apparatus base will be as indicated by the dotted lines 26- when a batter pile is to be driven at the lower right hand corner of this figure.

After the completion of the driving of all of the piles and the secure fastening of the frame structure with respect to the piles, it will be apparent that such frame acts as a strong support stiffening the long sections of all of the piles against deflection in horizontal directions. The piles are thus all thoroughly locked together at the level of the framework 20 as well as by and at the level of the patform frame 24.

It will be apparent that the above-described pile structure will have greater stability on account of the widening of the base of the structure as compared with the arrangements now most commonly used, wherein-it has been feasible only to use vertically driven piles. Also the cost and weight will be very much reduced compared with the usual existing practice, for the reason that the heavy and expensive steel braced stool type of structure hereinabove referred to, may be eliminated. The lesser number of vertical and diagonal portions in the Water naturally reduces the total force of the impact of waves against the structure. In addition, the. present invention makes it possible to provide offshore platforms in much deeper Water, since the individual piles may be made of great length and the batter piles may be spread out to any angle that is necessary to take the horizontal loads to which the structure may be subjected.

The structure of Fig. 3 is like that of Fig. 1, except that smaller additional piles as at 15", 16' etc. and 23 have been driven down through the hollow Cylindrical piles as at 15-18 and 23 to extend further down into the mud of the ocean floor. These internal piles while preferably formed as steel cylinders which are filled if desired, after being driven, with reinforcements and concrete, may alternatively be formed of wood or concrete rather than of steel or as steel shells. The outer larger cylindrical piles as at 15-43 and 23 may, if desired,.be formed as a series of concrete cylindrical sections prestressed by heavily tensioned Wires running through aligned apertures in the walls of the series, as disclosed in U.S. patent to Upson, No. 2,706,498,. granted April 19, 1955.

When the inner piles as at 15', .16, 23' have been driven down to a point where the resistance provides the required carrying capacity, they may be grouted to the outer piles by introducing under pressure grout therebetween as indicated at 36 in Figs. 9-12 inclusive. This exceedingly strong telescoping pile arrangement makes it possible to use a relatively smaller number of vertical and batter piles in the water, thereby reducing the total impact of the waves against the structure and at the same time makingpossible the location of the structure (5.

much deeper waters, since such piles may be made of m st indefinite en th and may be. pread out to. any desired batter necessary to withstand the horizontal loads. Such pile arrangements of extensive length and strength are particularly advantageous in certain areas, for example of the Gulf of Mexico, where adequate resistance to driven piles is sometimes not found until same are driven from to 200 feet below the sea bottom.

As shown in Fig; 4, the upper platform supporting frame may include braces as at 31, to which the guide portions as at 32 for the vertical piles, as well as the guide portions 25 for the batter piles, may be aiiixed as by welding, bolting or otherwise. As further shown in Figs. 9 and 10, the guide portions 32 may surround the vertical piles with some clearance space, closed at the bottom by a suitable annular packing means 33 (Fig. 10)

such space then being filled with grout 34, preferably introduced under pressure to firmly secure the member 32 to the concrete pile.

As shown in Fig. 5, the frame assembly 20 may include horizontally Positioned brace members as at 35 to 38 inclusive, suitably arranged to lock in effect the guide portions 29:; for the vertical piles with respect to the guide portions 22 for the batter piles. The brace memhers of this frame may be formed, for example, of tubular steel, or if desired, of other material such as reinforced concrete. As shown in further detail in Figs. 11 and 12,

the guide portions 22 which receive the batter piles -23 may each be formed of twosemi-cyindrical portions with flanges bolted together as at 40. It will be understood that the details of the construction of the frames at. 2B and 24 may be varied considerably depending upon the desired size and availability of materials and facilit es.

In Fig. 3, an oil derrick structure 41 is schematically indicated as mounted upon a completed platform. a

The embodiment of Fig. 6 is similar to that of Figs. 1 and 3, except for one significant difference, which under certain circumstances may be important and a preferable arrangement. That is, in Fig. 6 the batter piles, such as indicated at 45, are positioned so as to form diagonal braces of great strength for that portion of the structure between the upper frame or platform 46 and the generally submerged frame 47.. Thus the batter piles with thisarrangement cooperate with the vertical piles in the support of vertical loads and at the same time provided an exceptionally strong bracing against horizontal forces against the upper portions of the structure, as well as bracing the lower portions. as in Figs. 1 and 3. Furthermore, an important advantage of the arrangement of the batter piles of'Fig. 6 resides in the fact that with this arrangement barges-or ships, as indicated, may'approach the structure without danger. of colliding with the batter piles, since the; latter will protrude out beyond the vertical piles only at substantial depths.

Very serious damage might be caused if any floating equipment should be free to come into contact with any of'the supporting piles of the structure, particularly. during rough weather. To avoid this possibility, a fender arrangement may be used, such as indicated at the right hand side of Fig. 6, in order effectively to cushion the impacts of barges or ships. This may comprise prefer.- ably pluralities of prestressed concrete piles, or single piles as at 48 which are driven only a short distance into the sea bottom, and which are connected to and. in part supported by heavy resilient means, for instance, .'coil springs as indicated at 49. At the region of the water level, such piles may carry conventional timber means as indicated, to provide a rubbing face to be engaged by barges or ships, which, upon applying impacts or exerting pressure on the piles 48, will cause same to he deflected as indicated by the dotted lines 48', the ex.- tent of such deflection being resiliently limited by {@Q. son of the coil springs 49..

@A shown in Fig 7 nd 8. t s 1 pm; assigns: time 46 and 4'7 may be constructed according to general principles similar to those of Figs. 4 and 5, except with the appropriate alteration of the arrangement of the braces to accommodate the different positions of the guides or clamps for the several piles. Figs. 7 and 8 further show how each batter pile may be guided -as driven and positioned at an angle to extend from the top near one of the vertical piles, across toward an opposite vertical pile but at an angle inwardly of the iatter and thence at points below the lower frame out beyond the vertical piles at the desired batter into the ocean bottom. Since as indicated in Fig. 8, the guides or clamps for the batter piles on the frame 47 will be located all within the periphery of that frame, the batter piles may be guided and held against displacement with a frame structure which is compact and of exceptional strength.

It is contemplated that at some offshore locations, a number of oil wells will be driven respectively all in different directions from a single platform structure; For example, as many as ten oil wells may be thus driven from one structure, thereby greatly reducing the cost of the platform structure per well. in order to accomplish this, it is desirable to provide a platform which is for example 60 to 70 feet wide and 200 feet long, to carry all of the necessary equipment. Figs. 13 and 14 respectively are elevational and plan views showing how such an extensive platform as at 50 may be sup ported by groups of vertical and batter piles in accordance with the invention. For example, at the ends of the platform, two vertical piles as at 51 may be provided and accompanied respectively by batter piles 52 which are guided during driving and are retained in position thereafter by submerged frame means 53 similar in function and purpose to the frame means 2% and 47 above described. At other places, the platform 51 along its length may be supported for example by groups of four vertical piles as at 54, two of these being accompanied by crossed batter piles as at 55 extending out to one side of the platform and the two other vertical piles of the group being accompanied by similar batter piles 56 extending out to the other side of the platform. The frame means 53 may be made with additional sections as at 57, 58 etc. for interconnecting all of the piles, preferably below the water level and to provide guide means during the driving of the batter piles.

While in the case of prior heavy sunken frame structures for the purpose, as now generally used, it has been diflicult or impossible to remove same as an obstruction to navigation when they are no longer to be used in a given location, yet with the present invention each of the relatively small number of piles necessary may be readily cut off at a deep level by dynamiting and then readily removed if the platforms are no longer desired.

Although preferred embodiments of the invention are herein disclosed for purposes of explanation, various further modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains. Reference should accordingly be had to the appended claims in determining the scope of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. The method for constructing an offshore platform foundation, which comprises: individually driving substantially vertically a plurality of piles in spaced apart relationship with the lower portions of such piles being driven into the sea bottom and the upper portions thereof extending to a substantially height above the water level; thereafter lowering to a substantial distance below the desired platform level a frame having portions for securing said piles and also having means for guiding and bracing the midportions of batter piles to be subsequently driven at angles to said vertically driven piles; securing said vertically driven piles to the frame in their spaced positions; securing a platform to the upper portions of said vertically driven piles at the desired level above the water and at a substantial distance above said frame, said platform also having batter pile guide means; and driving batter piles from said platform downwardly into the sea bottom at angles to said vertically driven piles while said batter piles are guided, respectively, by their substantially spaced apart guide means on the platform and guide means on the frame.

2. The method for constructing an offshore platform foundation, which comprises: individually driving substantially vertically a plurality of piles in spaced apart relationship with the lower portions of such piles being driven into the sea bottom and the upper portions thereof extending to a substantial height above the water level; thereafter lowering to a substantial distance below the desired platform level a frame having portions for securing said piles and also having means for guiding and bracing the mid portions of batter piles to be subsequently driven at angles to said vertically driven piles, securing said vertically driven piles to the frame in their spaced positions; securing a platform to the upper portions of said vertically driven piles at the desired level above the water and at a substantial distance above said frame, said platform also having batter pile guide means; and driving batter piles from said platform downwardly from a point near the upper end of one of the vertical piles down to a point at said frame near another of tie vertically driven piles and thence down into the sea bottom outwardly of said vertical piles while said batter piles are guided, respectively, by their substantially spaced apart guide means on the platform and guide means on the frame.

3. The method for constructing an offshore platform foundation, which comprises: driving a pile substantially vertically at the desired location of the platform with the lower portion of such pile being driven into the sea bottom and the upper portion thereof extending to a substantial height above the water level; securing a guiding member to such driven pile for guiding a plurality of other substantially vertical piles at predetermined spaced apart locations; driving such other substantially vertical piles; thereafter lowering to a substantial distance below the desired platform level a frame having portions for securing said piles and also having means for guiding and bracing the mid portions of batter piles to be subsequently driven at angles to said vertically driven piles;

securing said vertically driven piles to the frame in their spaced positions; securing a platform to the upper portions of said vertically driven piles at the desired level above the water and at a substantial distance above said frame, said platform also having batter pile guide means; and driving batter piles from said platform downwardly into the sea bottom at angles to said vertically driven piles while said batter piles are guided, respectively, by their substantially spaced apart guide means on the platform and guide means on the frame.

References Cited in the file of this patent V UNITED STATES PATENTS 1,300,606 Hagenbuch Apr. 15, 1919 2,420,677 Peterson May 20, 1947 2,429,952 Willey Oct. 28, 1947 2,435,345 Freyssinet Feb. 3, 1948 2,574,140 Boschen Nov. 6, 1951 2,592,448 McMenimen Apr. 8, 1952 2,653,451 McCullough Sept. 29, 1953 2,736,172 McChesney Feb. 28, 1956 FOREIGN PATENTS 768,943 France May 28, 1934

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