US3597930A

US3597930A - Method and apparatus for reinforcing in situ in pile casing

Info

Publication number: US3597930A
Application number: US813479A
Authority: US
Inventors: William R Rochelle; Ronald Lee Wycoff
Original assignee: Brown and Root Inc
Current assignee: Brown and Root Inc
Priority date: 1969-04-04
Filing date: 1969-04-04
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10

Abstract

A method of reinforcing, in situ, a piling comprising the steps of: gaining access into the pile casing, cleaning mud and debris from the interior of the casing and simultaneously removing the debris, inserting stiffening or reinforcing material into the casing and sealing the pile casing access opening. The step of simultaneously cleaning and removing is essentially performed by a pile cleanout device comprising a fluid jetting portion operable to dislodge and fragment sediment and other debris within the jacket pile casing, and a gas lift portion integral therewith to remove the fragmented matter from the interior of the pile casing.

Description

United States Patent [72] Inventors [21 Appl. No. [22] Filed [45] Patented [7 3 Assignee [54] METHOD AND APPARATUS FOR REINFORCING 1,013,758 1/1912 Foxetal 1,729,422 9/1929 Gleasner til/53.52 2,018,284 10/1935 Schweitzer 15/104.05 X 2,443,721 6/1948 Butcher, .lr.... 134/24 2,702,180 2/1955 Homer 175/69 2,735,794 2/1956 Fletcher 134/24 3,483,707 12/1969 Meheen 61/46 Primary Examiner-Jacob Shapiro AttorneyBurns, Doane, Benedict, Swecker & Mathis ABSTRACT: A method of reinforcing, in situ, a piling comprising the steps of: gaining access into the pile casing, cleaning mud and debris from the interior of the casing and simultaneously removing the debris, inserting stiffening or reinforcing material into the casing and sealing the pile casing access opening. The step of simultaneously cleaning and removing is essentially performed by a pile cleanout device comprising a fluid jetting portion operable to dislodge and fragment sediment and other debris within the jacket pile casing, and a gas lift portion integral therewith to remove the fragmented matter from the interior of the pile casing.

6 Sheets-Sheet 1 I IN" Patented Aug. 10, 1971 INVENTORS WILLIAM R. ROCHELLE RONALD LEE WYCOFF BY ar/1r Dom, euuhbc,

\Ymutu Hat/wk ATTORNEYS Patented Aug; 10, 1971 6 Sheets-Sheet 2 INVENTORS WILLIAM R. ROCHELLE RONALD LEE WYCOFF Eur/11 boa/w, gamma; BY @Mzafv: Harm ATTORNEYS Patented Aug. 10, 1911 3,597,930

6 Shoota-$hoet 15 6 INVENTORS WILLIAM R. ROCHELLE RONALD LEE WYCOFF BY ums 50m, e/Lenubt,

Shea/m1 2 Maw/u:

ATTORNEYS Patented Aug. 10, 1971 6 Sheets-Sheet 4 FIG 9 INVENTORS WILLIAM R. ROCHELLE RONALD LEE WYCOFF ums, 2mm, Beanbag Mac/w Mum ATTORNEYS Patented Aug. 10, 1971 3,597,930

6 Sheets-Sheet 5 so mi 73 77 5 7s 79 f\ b. 1

FIG ll FIG [3 INVENTORS WILLIAM R. ROCHELLE RONALD LEE WYCOFF ums, boa/Le uest/w,

Smok 75 Mmm ATTORNEYS Patented Aug. 10, 1971 3,597,930

6 Sheets-Sheet 6 INVENTOBS WILLIAM R. ROCHELLE RONALD LEE WYCOFF ELL/Ill boa/u mau'ot,

Qwec/cer 8? Maflulr ATTORNEYS tion, or may be 'used, for other .ry for a number of reasons.

METHOD AND APPARATUS FOR REINFORCING IN SITU IN PILE CASING BACKGROUND OF THE INVENTION This invention relates to reinforcing, in situ, an offshore piling of the type adapted to extend downwardly into the bed of a body of water and upwardly above the surface of the water to support a platform. I

More particularly this invention relates to a method and ap paratus for reinforcing pilings, in situ, which may be partially damaged or corroded and' which may contain silt or other sediment that would prohibit, the utilization of conventional pile-reinforcing techniques.

Drilling for oil in oilfields or gasfields situated beneath the surface of a body of water such as a sea or lake is frequently performed utilizing a drilling tower which is relatively mobile and generally includes a buoyant base adapted to rest upon a submerged surface. In contrast theinstant invention relates to an-offshore platform or tower which has pilings extending into a submerged surface and is therefore relatively immobile. Such a platform may be used in conjunction with a well or several wells, may be used as a distribution or collecting stalated to the petroleum industry.

One example of a platform support structure of the type describedabove' includes a plurality of vertically extending tubular casings which have been either jetted, driven, or drilled into the seabed. In many cases, depending upon the depth of the water, the casings comprise segments which are directed into alignment by guide flanges and either bolted, screwed or welded together at the construction site. Cross bracing is frequently employed to give the structure lateral stability against hydrodynamic loads imposed on the piling by currents and/or waves within the sea.

Platforms, as described above, in addition to supporting 1 I drillingequipment, frequently are used to support radarjnstallations, lighthouse beacons, marine experimentation stations, and the like. Dimensionally the pilings of these platforms frequently vary from 6 inches to 3 feet in diameter and from 50 to 100 feet in'length or more when used along the near shore portions of the Gulf of Mexico and 100 to 500 feet or more in length when used-along the Continental Shelf of the Although tubular platform supports of the type described are often adequate, they may sometimes become unsatisfacto- For example, in areas where sea conditions vary with the seasons, the above structure may be quite satisfactory, on a temporary basis. However, if the tower is required to be maintained through a'stormy season, the tubular casing may not be structurally rigid enough to withstand forces created by a raging wind and sea. q

Another disadvantage of theabove tubular pile structure is purposes, not necessarily re that while a pilinginitially may be designed to withstand vary- I ing sea conditions, with time, the steel casings may be corroded and often substantial portions may be eroded away. It will be readily appreciated that such corrosion, or fatigue will substantially weaken the piling structure, even to the point of possible failure.-

One particular environment where convention supports have not been totally satisfactory is for offshore drilling operations. In this regard, while conventional tubular structure can be designed towithstand the stresses and corrosion of the salt water for an estimated drilling time, frequently drilling operations are extended beyond the time initially estimated. Furthermore, if the drilling produces an oil-bearing well, the drilling platform is frequently used to support production equipment which can remain in place indefinitely.

When either of "the above conditions occurs, some means is necessary to reinforce the supportpilings without disrupting either the drilling or subsequent production operations. Un-

SUMMARY or THE mamas Objects of the Invention To this and-other ends, it is therefore a general object of the invention to overcome problems and disadvantages of the type previously mentioned.

It is a particular object of the invention to reinforce, in situ, conventional pile casings.

It is another object of the invention to reinforce, in situ, weakened pile casings of offshore drilling platforms.

It is yet another object of the invention to reinforce pile casings without disrupting operations on the platform supported by the pilings.

Itisa further object of the invention to provide a means to reinforce temporary piling structure, in situ, after a decision has been made to make the structure relatively permanent.

It is still another object of the invention to reinforce a piling structure which maybe substantially full of sediment or debris and which contains inwardly projecting guide means which facilitate the joining of pile segments.

It is yet another significant object of the invention to provide a device that can be positioned within a pile casing and simultaneously fragment and remove debris therein.

It is a further object of the invention to provide a device that is lightweight and compact enough to fit into a pile casing and fragment and remove debris therein at depths far exceeding sea level. I I

It is yet a further object of the invention to provide a device with no moving parts, that is not vulnerable to abrasion, that is conservative in power requirements, that will not be clogged by mud or debris and will be compact enough to fit into a pile casing to fragment and remove debris therein at depths greatly exceeding sea level. a

One preferred form of the invention intended to accomplish at least some of the foregoing objects comprises: gaining access into a pile casing above the waterline, cleaning debris from the interior of the casing and simultaneously ejecting this debris from the pile casing,'stiffening or reinforcing the casing and finally closing the pile casing access opening.

In carrying .out the above step of cleaning and simultaneously ejecting another aspect of the invention comprises a fluid jet cleaning and gas lift pumping tool. The tool is designed to descend into a pile casing and generally comprises two cylindrical chambers. One chamber contains jetting nozzles at one end thereof and a fluid inlet at the other end. Pressurized fluid can be pumped into this chamber where it will momentarily accumulate and then jet against the casing walls to fragment matter that may be collected thereon or therebetween.

The second chamber is integrally connected to the first acdebris within the chamber and thereby redu'cethe specific gravity of the fluid within the pump. Consequently, the fluid column outside the chamber will force the fluid of lower specific, gravity inside the chamber to the surface through a conduit connected to the top of the pumping chamber.

I THE DRAWINGS Further objects and advantages of theinvention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view, partially broken away, of a portion of the pile-defined support structure for an offshore platform;

FIG. 2 is a partially sectioned side elevational view of a piling during the cleaning phase of reinforcing the piling;

FIG. 3 is a partially sectioned side elevational view of a piling during the dewatering step of reinforcing the piling;

FIG. 4 is a partially sectioned side elevational view of a piling with prestressing tendons positioned therein;

FIG. 5 is a sectional side elevational view of the prestressing structure;

FIG. 6 is a top plan view of the prestressing structure, as viewed along section line 6-6 of FIG. 5;

FIG. 7 is a partially sectioned side elevational view of a prestressed reinforced piling casing;

FIG. 8 is a partially sectioned side elevational view of a preferred embodiment of a pile cleanout device positioned with a pile casing;

FIG. 9 is a cross-sectional view of one of the nozzles shown in FIG. 8;

FIG. 10 is a top plan, generally horizontally sectioned view of the pile cleanout device shown in FIG. 8, as viewed along section line 10-10 of FIG. 8;

FIG. 11 is a fragmentary, partially sectioned, vertical elevation view of the upper end of a guide component as viewed along section line 11-11 of FIG. 10;

FIG. 12 is a fragmentary partially sectioned, vertical elevation view of the high-pressure manifold, as viewed along section line 12-12 ofFIG. 10;

FIG. 13 is a cross-sectional view of the manifold shown in FIG. 12, taken along section line 13-13 therein;

FIG. 14 is a partially sectioned side elevational view of an alternative preferred embodiment of a jacket pile cleanout device shown positioned within a jacket pile casing wherein conduit 32 has been rotated 60 for ease of illustration;

FIG. 15 is a top plan view, generally horizontally sectioned, of the pile cleanout device, as viewed along section line 15-15 of FIG. 14;

FIG. 16 is a bottom plan view of FIG. 14; and

FIG. 17 is a fragmentary portion of a cross-sectional plan view taken along section line 17-17 of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Summary Referring now to the drawings, wherein like numerals designate like parts, and more specifically to FIG. I, an offshore platform structure 10, only a portion of which is shown, is pictured supported by a plurality of generally upright pile casings 11. Such pile casings 11 project through generally tubular jacket legs" 11a of the structure 10 to secure structure 10 to the subsea bed 13, in the manner generally described in the U.S. Pat. No. 3,315,473 to I-Iauber et al. and the U.S. Pat. No. 3,429,133 to Hauber.

The casings 11 extend above the surface 12s and into the bed 13 ofa body of water 12. Crossbracing means 14 extend between and reinforce the jacket legs 110 so as to restrain lateral movement of the structure, which may be caused, for example, by various hydrodynamic forces of the sea.

The pilings 11 may contain sediment and debris 15 which has accumulated above the seabed and also a more compacted silt or deposit 16 below the seabed.

A preferred method of reinforcing, in situ, a piling, as described above comprises: swagging internal guide flanges of easing segments into conformity with the casing wall, cleaning and simultaneously removing any sediment or debris that may be contained therein, dewatering the pile casing, filling the casing with a cementitious material and prestressing the cement. A piling reinforced by the above method may be stronger than the original tubular casing and extremely resistant to the hydrodynamic forces of the sea.

The above step of cleaning and simultaneously removing sediment within the piling is carried out by a jacket pile cleanout device as best seen in FIGS. 8 and 14. The cleanout device is compact enough to be positioned within the jacket piling and is composed of an accumulation jetting chamber with a plurality ofjetting heads at one end thereof. The heads direct fluid jets against compacted silt within the casing. The fluid jets fragment or disperse the silt which will then be suspended within the jetting fluid retained within the casing.

Integral with the accumulation jetting chamber is a generally hollow, open-ended tubular pumping chamber. The pumping chamber contains a gas inlet means which will admit superatmospheric gas into the chamber. The gas will comingle with the jetting fluid and the fragmented debris which, following a path of least resistance, has entered the open end of the pumping chamber. Therefore, the solution in the pumping chamber will have a specific gravity lower than the fluid outside the chamber and will therefore be pushed upward. This means of pumping is commonly referred to as a gas lift.

It will be readily appreciated by those skilled in the art that the above-described tool will simultaneously scour the interior of a pile casing and pump the fragmented debris to the surface and out of the jacket piling. It will be further noted that this pumping device does not contain any moving parts and therefore is relatively simple to service. Since the pumping chamber is merely a smooth hollow opening, mud and debris will not clog or wear the interior as readily as with a rotary vane pump. Further, the pump as described above is small enough to fit into the interior of a pile casing, yet is large enough to fulfill the pumping requirements. Additionally, the pump will operate at depths far exceeding those possible by a perfect vacuum pump positioned at sea level.

The Method The first step in reinforcing a piling, in situ, is to form an entrance into the interior of the piling.

If it should prove to be impractical to provide an access into the top of the piling structure, a service window 20, shown in FIG. 1, may be cut into the contiguous sides of the piling and jacket leg to be reinforced. A temporary service platform 21 may be constructed around the jacket leg and piling, beneath the location of window 20. The platform is supported by braces 22 attached to the exterior of the jacket structure and for safety a guardrail 23 may be placed around the platform perimeter.

In those instances where the piling was constructed with pipe segment stabilizing or guide means, 19, a swagging tool 24, shown in FIG. 1, is inserted into the lateral opening. The tool contains a plurality of expanding lobes 25. The lobes are placed next to the weblike section 19a, guide means 19, which are inclined toward the pile axis, and expanded to swage the weblike sections outwardly into general conformity with the interior of the pile casing 11. Swagging tools 24 are commercially available and well known to those skilled in the art.

After the guide sections 19a have been flattened, the swagging tool is removed and a pile cleanout tool 26, shown in FIG. 2, is positioned within the jacket pile opening 20 and lowered down the pile casing on a rolling guide sled 27. Fluid is pumped down a conduit 30 into an accumulation chamber 28 and forced through jetting heads 29 into the casing interior. If the casing is initially water free, fluid exiting from jets 29 will build up a substantial waterhead, as shown at 37. As the tool encounters mud or silt within the casing, water from the plurality of high-pressure jets 29 will fragment or disperse the mud and silt, forming a generally homogeneous suspension of water and debris around the end of the cleanout tool.

Superatmospheric air is then forced through a conduit 32 into a toroidal manifold 33 and out of a plurality of apertures 38 contained therein, as shown in FIG. 12. The high-pressure air will comingle with the homogeneous suspension of fluid and silt which has entered the pumping chamber and substantially reduce its specific gravity. As discussed before, since a head of water 37, which water has a specific gravity of substantially unity, exists outside a preferably stiff, andpossibly water andaparticulate matter having specific gravity less than that ofwater 37 exists within metallic conduit 35, the foamed liquid and particulate matter will be forced to the surface and expelled at lower lip 36 of window 20.

metallic conduit 35, and a column of foamedf' 'or aerated" Therefore, as the jacket pile cleanout tool descends into the v pile casing,.thefluid from jets 29 disperses mud and siltcontenance of ahydrostatic head. Therefore, eventhough the jacket pile cleanout device can substantially remove'mud and g silt from. the interior of the casing, it will necessarily leave a considerablcamount of liquid within the pile casing.

In some: circumstances, where .the reinforcement merely comprises-filling the casing with a stiffening material, the

asphalt, grouting :or other cementitious material will merely displace the fluid ash is pumped into the.piling.-H.owever, where a cementitious column is to be prestress'ed, it is-desira- 1 bleto substantially dewater the piling before working-within it.

The dewatering can beaccomplished by lowering a conventional rotary, vane pump 39, generallydepicted in FIG. 3, into thepiling casing. The pumpend 40 is submerged into the fluid contained in the casing. As the fluid levelrecedes, the pump can be lowered to maintain the inlet below thewaterline. It will be readily appreciated by those skilled in :the art that a pump of=this.type would have been unacceptable, initially because its rotary vanes would have been clogged by the mud and siltwithin thepiling. Further, it would have occupied. too much'space to be utilized with a-cutting tool and for other reasons as priorly enumerated.

After the water' within the pile casing is substantially removed, the pump 39 iswithdrawn and a-reinforcing bundle is inserted within the casing. walls. The reinforcing bundle is composed of a pair of endaplates 41 and .42, as best seen in FIGS. 4, .5 and 6,.and a plurality of reinforcing rods' or tendons 43 extending between the two end plates; Theend platesare provided with centralpassages 47 and 48 to allow the piling to be filled with cementitiousmaterial, as will be described later.

Each of the reinforcing rods is surrounded by a tubular sheath 44 which is spaced radially therefrom. The rods 43- are secured to the end plates by conventional prestressing' washers 45. The upperplate. is attached tothe.interior of the casing wall by a plurality of support bars 46; ltwillbereadily appreciated by those-skilled in the art that the structure of the reinforcingcage, while flexible, may dictate slightly enlarging opening:20-to accommodate its insertion into the pile casing. ln thoseinstances where the'accessopening is-provided in the top ofthe piling, formingor enlarging'a sideaccess access, of course, would be unnecessary.

. Once the'reinforcing cage issecured within the pile casing, the opening 47 in the top platepermits the pile to be pumped substantially full ofa fluid cementitious material 120. The cementis'allowedto'set and partiallyl'cure' until it'reaches an adequate'strengthto'be stressed. The tendons are then tensioned by conventional machinery suitable for the purpose, such as a hydraulic ram.

Allowing-the cementto partially cure-beforestressing insures. a relatively rigid column for the end plates to bear against and further excessive hoop and shear stresseson the piling casing are avoided.

The cement is allowed to fully cure in the prestressed condition. A binder materialis then pumped through passages (not shown) in the stressing washers into thesheaths 44surrounding the reinforcing rods 43 to bind the tendons to the sheaths. thus creating an integral prestressed structure, shown in FIG. 7. The end plate 41 is then covered with concrete and window 20is sealedwith a closing plate, not shown.

. 6 By following the above-outlinedsequence ofsteps, a jacket piling-which was either originally designed as a temporary structure or one that had substantially deteriorated through corrosion has been rejuvenated by the construction therein'of'.

a prestressed concrete column which will stiffen the pilings and carry considerably more stress, without. failure, than the original tubular structure.

The Jacket Pile Cleanout- Tool A preferred embodiment of a jacket pile cleanout tool, as

shown'in FIG. 8, positioned within a pile casing 11, comprises a first generally closed cylindrical accumulation jetting chamber 51. 1

A plurality of jetting nozzles, generally indicated as 29, protrude from the .lower end of the chamber 51 in three echelons. A first penetration nozzle 121 is centrally located 1 directly on the bottom of the accumulation chamber. This nozzle serves to jet a leading holewhichvertically penetrates clean fluid will be unobjectionable since materials, such as and preconditions mud within the piling 11.

The penetration nozzle is followed by a circumfe'rentialrow of cutting and fragmenting nozzles 122. These nozzles extend from the sidewalls of the accumulation chamberand project downwardly at an angle approximately 45 (degrees) to the vertical. Descent of the penetration nozzle 121- bringsthe main cutting and fragmenting nozzles into proximity with" the.-

sloping faces, approximately 45 (degrees),.of preconditioned r or partially softened mud. Fluid jetting from the nozzles 122- meets the wall of prcsoftened mud at an angleapproximately normal to the slope of the mud wall and therefore penetratev and disperse substantially all of the mud within the piling'll.

The main cutting nozzles 122 are followed by a final echelon of circumferentially spaced scouring nozzles 123. The scouring. nozzles are circumferentially positioned to straddle the spacing of the cutting nozzles l22'and'extend'downwardly at an angle of approximately 60 (degrees) with the vertical;

The function of the scouring nozzles 123 is to jet againstand disperse'any mud clinging to the piling wall which the cutting nozzles 122 did not disperse, therefore substantially scouring and cleaning the'piling walls of all debris.

The nozzles, as shown in FIG. 9, are designed with a first frustoconical inlet passage 53 which gradually reduces -toa jetting passage 52. The size of the nozzle varies with the job and they are, therefore, interchangeably attached to-the accumulation chamber by collars 56. Further, the jetting passage of each nozzle is provided with a hardened surface 52a or a wear insert (not shown) to maximize nozzle life.

Atthe top of the jetting accumulation chamber 51 is an entrance conduit 59 which is connected directly, through a'conventional threaded coupler 60, to a high-pressure fluid conduit 30. Additionally,-at the upper end of the jetting accumulation chamber is a support tab 57'containing'an apertureSS therein, to provide a ready connection for a wire support rope, not shown.

integrally, attached by means of a coupling plate6l to the above-described jetting accumulation chamber 51, is a pumping chamber 31. The pump contains an opening 62-in the lower end and has a triangular cross-sectional, toroidal manifold 33 attached to the interior thereof.

The manifold 33, as shown in FIG. 12, comprises-a pair of circumferentially extending

legs

63 and 64. The legs are welded together at one end by a weld bead 65and'angularly slope to the wall of the pumping chamber where they are united theretoby a pair of

weld beads

66 and 67. Therefore, a triangular, toroidal manifold is formed on the interior surface of the pumping chamber. The triangular shape of the manifold projecting into the flow stream of the pump 31 will produce a the orifices 38 clean..

A high-pressure air (or gas)-line 32 is connected to the pumping chamber 31 and opens directly into the interior of the high-pressure manifold through an aperture 68 in the pumping chamber wall. As best seen in F108. 12 and 13, the high-pressure manifold contains a plurality of upwardly facing orifices 38 spaced in two circumferential rows within the upper leg of the manifold structure. The orifices provide a uniform array of multiple entrance for high-pressure gas into the interior ofpumping chamber 31. It will also be appreciated by those skilled in the art that providing orifices 38 in the upper leg only of the manifold 33 will prevent mud and debris from entering and clogging the manifold passage.

At the upper end of the pumping chamber is a low-pressure swivel joint 69 and a cam-type coupler 70 such as that disclosed in US. Pat. No. 2,518,026.

A jacket pile cleanout device of this particular embodiment is frequently used with casings approximately 30 inches in diameter or greater. Therefore, in order to insure the maintenance of the jetting head approximately in the center of the casing, and to keep the cleanout device from tilting and wedging within the jacket pile a rolling centralizing support or sled, generally indicated 27, as shown in FIG. 8, is positioned around the accumulation chamber 51.

The rolling support comprises an upper set of three radially disposed support arms 71 and an identical lower set ofsupport arms 72. A first arm 73 is positioned diametrically opposite to the pumping chamber 31. Journaled vertically between arm 73 and its lower counterpart is a rectangular casing 74 which serves as a base for an upper and lower set of bifurcated caster brackets 75. Caster wheels for rolling contact with the interior of the pile casing 11 are journaled on each of the brackets 75.

In order to prevent the support bar 74 from rotating around an axle pin 77, under working conditions, an aperture 78 is formed in the support arm 73 and a corresponding aperture is fashioned into a keeper tab 79 which extends from the support bar 74. As best seen in H0. 11, to lock the rollers into an operative position, the apertures in support arm 73 and keeper tab 79 are aligned and a locking pin 80 is dropped therethrough.

The other two pairs of support arm 81 are positioned approximately 120 on either side of support arm 73 and are distinguishable therefrom by the addition of a second support bar locking position. When a locking aperture 82 is utilized, the rollers extend radially from the accumulation chamber 51, which is the normal operating position. However, when it is desired to insert or withdraw the cleanout device from a pile casing, these rolling supports can be swung approximately 60, as indicated by phantom lines in H0. 10, and locked in position utilizing an aperture 83. Therefore, it is possible to insert the cleanout device into the pile casing through a smaller service window than would be feasible if these two rolling supports would not laterally rotate.

The above-described embodiment of the jacket pile cleanout device echelons, particularly suited to relatively large casings, although not limited thereto. When casings are encounterd which have a small diameter, another embodiment of the jacket cleanout device may be preferred and is disclosed by FIGS. 14-17.

As best seen in FIG. 14, the cleanout tool comprises a fluidaccumulating jetting chamber 90. This chamber comprises a central cylindrical body member 91 with an upper cap 92 and a lower cap 93. The lower cap is provided with a plurality of hemispherically arranged nozzles 94, as best seen in FIGS. 14 and 16. The nozzles are positioned in three echelons, as discussed previously, for penetrating, cutting and scouring. The nozzles are provided with a cylindricaljetting bore 95 and are interchangeably connected within a plurality of end cap threaded apertures 96.

The upper end cap 92 is provided with an inlet passage 97. Coupled directly to this passage is a high-pressure fluid conduit 98 which is attached to inlet pipe 30 by a conventional threaded fastener 99.

Concentrically surrounding the accumulation jetting chamber 90 is a gas lift pump 100. The pump comprises a generally cylindrical chamber 101 which is open at its lower end, as at 102, and is provided with a reducing cap 103 at its upper end which opens directly into an outlet conduit 104. The outlet conduit is coupled to exhaust pipe 35 by a quick release cam coupling 70. The high-pressure fluid conduit 98 passes through the reducing cap 103 and is provided with a seal weld 124.

The upper reducing cap 103 has integrally attached thereto a support car 105, as shown in FIG. 15, with an aperture 106 therethrough. The ear is suitable for connection to a flexible metallic support cable.

Positioned within the pumping chamber 100 is a generally triangular toroidal high-pressure manifold 107, which, as best seen in FIG. 14, is composed of an upper peripherally extending side 108 and a lower peripherally extending side 109. These sides are angled together and extend about and are directly welded to the cylindrical portion 91 of the accumulating jetting chamber 90. Therefore, the chamber serves as a base for the toroidal manifold.

The upper side 108 of the manifold is provided with an inlet aperture 110, which accommodates a high-pressure airline 32 and provides an entrance into the manifold 107. The upper side 108 of the manifold 107 is further provided with a plurality of upwardly facing apertures 111. A triangular manifold, as discussed previously, provides an advantageous means of pumping air into the chamber and the upwardly directed orifices 111 prevent clogging of the manifold 107. The apex 112 of the triangular manifold radially falls short of extending to the inner periphery of the pumping chamber 101, therefore an annular space 113 is maintained to allow water and particulate matter to enter the pumping chamber around the outside of the manifold and to be therefrom lifted to the surface by gas lift techniques as described above.

SUMMARY OF THE ADVANTAGES It will be appreciated by those skilled in the art that the above disclosure provides a method and means of reinforcing, in situ, a weakened jacket pile casing which may contain obstructions and which may be filled with mud or other debris.

In addition, the above-described jacket pile cleanout tool when utilized as directed can be inserted into a piling, in situ, to scour the interior thereof without necessitating a shutdown on the work platform.

The cleanout tool as described above comprises a unitary structure that can be positioned within a piling to penetrate, fragment and scour mud from the interior thereof and pump the debris to the surface even at depths greatly exceeding sea level.

The tool is light weight, dimensionally compatible with conventional piling casings, and is essentially abrasion resistant and nonclogging.

The sloping lower wall of the triangular manifold channels fluid into the pumping chamber and may thus assist in keeping the air-supplying orifices clean."

The invention has been described in connection with a technique involving the post-tensioning of the reinforcing elements 43. This technique is advantageous in that substantially no axial stress is imposed upon the piling to be repaired or strengthened. However, in certain instances, it may be permissible to secure the

plates

41 and 42 to the piling interior and pretension the members 43 before the cement is introduced into the piling to surround these reinforcing members. After the cement was introduced and cured, the members 43 would be relaxed so as to cause the

plates

41 and 42 to axially, compressively engage the cement mass.

As will also be recognized, the practice of the invention is not limited to the repairing of conduits having an essentially upright configuration.

Although the invention is described with reference to preferred embodiments, it will be appreciated by those skilled in the art that additions, deletions, modifications, substitutions and other changes not specifically described and illustrated in these embodiments, may be made which will fall within the purview of the appended claims.

What we claim is: l. A method of rejuvenating and strengthening a pile casing supporting an offshore platform, the casing being at least partially filled with sediment or debris, the method comprising:

providing an access opening into a pile casing;

inserting a cleaning tool through said opening into the pile casing; using the cleaning tool, cleaning the interior of the pile casing, y dislodging matter from .the interior of the pile casing, by jetting a liquid against the matter whilesimultaneously pumping the matter up to and out of the opening, to thereby substantially remove the sediment or debris from the interior of the pile casing;

withdrawing said cleaning tool from the interior of the pile casing;

inserting a pump into the pile casing;

using the pump, pumping the pile casing substantially free of the liquid therein; a

removing the pump from the pile casing; and

substantially filling the interior of the casing with a stiffening material to reinforce thejacket piling.

2. Amethod of rejuvenating and strengthening ajacket pile casing as defined in claim I and further comprising the step of:

inserting reinforcing elements into the interior of said casing prior to substantially filling the casings .with stiffening material.

3. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 1 wherein the matter is pumped up to and out of the casing by,

forcing compressed air into a fluid exit column, to thereby lift the matter to the casing window by a gas lift.

4. A method of rejuvenating and strengthening a pile casing supporting an offshore platform, the casing being at least partially filled with sediment or debris, the method comprising:

providing an access opening into a pile casing;

inserting a cleaning tool through said opening into the pile casing;

using the cleaning tool, cleaning the interior of the pile casing, by

jetting a fluid against the debris within the interior of the pile casing, thereby dislodging and fragmenting it, while simultaneously 7 forcing super atmospheric gas into the interior of said cleaning tool to reduce the'specific gravity of the debris within the interior of the tool relative to the specific gravity of the fluid sediment and debris exterior of the tool whereby the fluid sediment and debris interiorly of the tool will be forced upwardly and expelled from the pile casing; and

substantially filling the interior of said casing with a cementitious material, thus reinforcing said pile casing.

5. A method of rejuvenating and strengthening ajacket pile casing as defined in claim 4 wherein said step of jetting comprises:

pumping a fluid under high pressure through nozzles at the end of the cleaning tool.

6. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 4 and further comprising the step of:

' pumping said jacket pile free of excess liquid and inserting reinforcing elements into the interior of the casing prior to filling the casing with cementitious material, and prestressing said cementitious material.

7. A method of rejuvenating and strengthening a pile casing extending from beneath a seabed to above sea level which supports an ofishore platform thereupon, wherein said casing may be filled with water, sediment or other debris, comprising the steps of:

cutting a service window into a lateral portion of a pile casinserting a swagging tool into said pile casing;

using the swagging tool, swagging pile casing guide means into conformity with the interior cylindrical surface of the ,pile casing;

removing the swagging tool from the pile casing;

lowering a cleaning tool into the pile casing;

using the cleaning tool, cleaning the interior of the pile casing, by

jetting a fluid against debris within the interior of said pile casing, thereby dislodging and fragmenting it, while simultaneously gas lifting the fragmented debris out of the interior of the casing, to thereby substantially remove the debris from the pile casing;

withdrawing said cleaning tool from the interior of the pile casing;

inserting a pump into the pile casing;

using the pump, pumping the pile casing substantially free of liquid therein;

removing the pump from thepile casing; inserting reinforcing elements into the interior of the pile casing; I substantially-filling the interior of the pile casing with a cementitiousmaterial;

allowing the cementitious material is set and partially cure;

tensioning said reinforcing elements, to thereby place said partially cured cementitious material under compression;

allowing the cementitious material to fully cure under compression, thus reinforcing said pile casing with a prestressed column.

8. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 7 wherein said step of gas lifting comprises:

forcing compressed air into a fluid exit column, to thereby lift said fragmented debris to the casing opening by the difference in specific gravity of fluids within the exit column and the pile casing.

9. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 7 which further comprises the steps of:

isolating the reinforcing elements by,

surrounding said elements with cylinders prior to inserting them into the interior of said casing, so that during the step of filling the interior of said casing with material the reinforcing elements will be isolated from said cementitious material; and

binding said tensioned reinforcing elements to the cylinders after the cementitious material has fully set by, inserting a binder between said reinforcing elements and said cylinders.

Claims

1. A method of rejuvenating and strengthening a pile casing supporting an offshore platform, the casing being at least partially filled with sediment or debris, the method comprising: providing an access opening into a pile casing; inserting a cleaning tool through said opening into the pile casing; using the cleaning tool, cleaning the interior of the pile casing, by dislodging matter from the interior of the pile casing, by jetting a liquid against the matter while simultaneously pumping the matter up to and out of the opening, to thereby substantially remove the sediment or debris from the interior of the pile casing; withdrawing said cleaning tool from the interior of the pile casing; inserting a pump into the pile casing; using the pump, pumping the pile casing substantially free of the liquid therein; removing the pump from the pile casing; and substantially filling the interior of the casing with a stiffening material to reinforce the jacket piling.

2. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 1 and further comprising the step of: inserting reinforcing elements into the interior of said casing prior to substantially filling the casings with stiffening material.

3. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 1 wherein the matter is pumped up to and out of the casing by, forcing compressed air into a fluid exit column, to thereby lift the matter to the casing window by a gas lift.

4. A method of rejuvenating and strengthening a pile casing supporting an offshore platform, the casing being at least partially filled with sediment or debris, the method comprising: providing an access opening into a pile casing; inserting a cleaning tool through said opening into the pile casing; using the cleaning tool, cleaning the interior of the pile casing, by jetting a fluid against the debris within the interior of the pile casing, thereby dislodging and fragmenting it, while simultaneously forcing super atmospheric gas into the interior of said cleaninG tool to reduce the specific gravity of the debris within the interior of the tool relative to the specific gravity of the fluid sediment and debris exterior of the tool whereby the fluid sediment and debris interiorly of the tool will be forced upwardly and expelled from the pile casing; and substantially filling the interior of said casing with a cementitious material, thus reinforcing said pile casing.

5. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 4 wherein said step of jetting comprises: pumping a fluid under high pressure through nozzles at the end of the cleaning tool.

6. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 4 and further comprising the step of: pumping said jacket pile free of excess liquid and inserting reinforcing elements into the interior of the casing prior to filling the casing with cementitious material, and prestressing said cementitious material.

7. A method of rejuvenating and strengthening a pile casing extending from beneath a seabed to above sea level which supports an offshore platform thereupon, wherein said casing may be filled with water, sediment or other debris, comprising the steps of: cutting a service window into a lateral portion of a pile casing; inserting a swaging tool into said pile casing; using the swaging tool, swaging pile casing guide means into conformity with the interior cylindrical surface of the pile casing; removing the swaging tool from the pile casing; lowering a cleaning tool into the pile casing; using the cleaning tool, cleaning the interior of the pile casing, by jetting a fluid against debris within the interior of said pile casing, thereby dislodging and fragmenting it, while simultaneously gas lifting the fragmented debris out of the interior of the casing, to thereby substantially remove the debris from the pile casing; withdrawing said cleaning tool from the interior of the pile casing; inserting a pump into the pile casing; using the pump, pumping the pile casing substantially free of liquid therein; removing the pump from the pile casing; inserting reinforcing elements into the interior of the pile casing; substantially filling the interior of the pile casing with a cementitious material; allowing the cementitious material is set and partially cure; tensioning said reinforcing elements, to thereby place said partially cured cementitious material under compression; allowing the cementitious material to fully cure under compression, thus reinforcing said pile casing with a prestressed column.

8. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 7 wherein said step of gas lifting comprises: forcing compressed air into a fluid exit column, to thereby lift said fragmented debris to the casing opening by the difference in specific gravity of fluids within the exit column and the pile casing.

9. A method of rejuvenating and strengthening a jacket pile casing as defined in claim 7 which further comprises the steps of: isolating the reinforcing elements by, surrounding said elements with cylinders prior to inserting them into the interior of said casing, so that during the step of filling the interior of said casing with material the reinforcing elements will be isolated from said cementitious material; and binding said tensioned reinforcing elements to the cylinders after the cementitious material has fully set by, inserting a binder between said reinforcing elements and said cylinders.