US2854825A

US2854825A - Magnetic jetting device

Info

Publication number: US2854825A
Application number: US424097A
Authority: US
Inventors: Wilfred S Crake
Original assignee: Shell Development Co
Current assignee: Shell Development Co
Priority date: 1954-04-19
Filing date: 1954-04-19
Publication date: 1958-10-07
Anticipated expiration: 1975-10-07

Description

Oct. 7, 1958 wl s, CRAKE 2,854,825

MAGNETIC JETTING DEVICE Filed April 19, 1954 2 Sheets-Sheet 1 Oct. 7, 1958 w. s. cRAKE 2,854,825

MAGNETIC JETTING DEVICE Filed` April 19, 1954 2 Sheets-Sheet 2 nited States Patent O 2,854,825 MAGNETIC JETTING DEVICE Application April 19, 1954, Serial No. 424,097 4 Claims. (Cl. 6180) Thisinvention relates to the drilling of oil and gas wells in sub-aqueous locations and pertains more particularly to an apparatus employed for the installation or removal of piles or pilings that are driven into the earth at sub-aqueous drilling locations and serve as a supporting structure for a drilling rig.

After drilling operations have been completed at a sub-aqueous drilling location, the majority of the pilings used as the sub-structure for the drilling rig are removed so as not to constitute a water hazard to boats or shipping. Since the pilings are normally driven many feet into the oor of the ocean, or into the earth formation below the body of the water in which they are located,

it is often difcult or impossible to pull the pilings out of the holes into which they had been driven because of the friction between the sands on the floor of the water body and the sides of the pilings. When it is impossible to remove the piles, they are either cut or blasted at a level well below the surface of the water and the lower parts of the pilings are left in the sands.

At times, it is possible to save many of the pilings by washing away the sand, gravel or other unconsolidated material from around the pilings. washing down along a piling driven into the sand beneath a body of water, it has been common to push a pipe down alongside the piling so that water under pressure can be jetted from the pipe to wash the sand from the piling and free it from the earth. This operation is based on the fact that once a hole is washed clean on one or more sides of a pile, the earth skin friction against the pile is reduced to a low figure so that the pile may be removed with relative ease by winding a cable or wire line around the top of the pile and pulling it upwardly by means of a hoist.

The use of jet pipes for jetting water alongside of a pile is not entirely successful in many cases in that the jet pipes do not readily follow the side of the pile as they are forced downwardly alongside the pile. In many cases, the jet pipes wander uncontrollably away from the pile, thus destroying or greatly minimizing the jetting effect for loosening the sand around the pile.

Since the majority of pilings used in sub-aqueous drilling operations are made of steel, it is the primary object of this invention to provide an apparatus for directing a stream of high pressure fluidv alongside the steel pipe for washing the sand therefrom, said apparatus being maintained in its position against the steel piling throughout its downward travel by magnetic means.

A further object of this invention is to provide a magnetic apparatus adapted to jet water to wash unconsolidated material from around steel pilings and to maintain its position against the steel piling at all times, either while being forced downwardly alongside the piling or while being moved around the periphery of the piling.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

Figure 1 is a longitudinal view of the present jetting apparatus.

Figure 2 is a longitudinal view, partly in cross-section, of the lower end of the jetting apparatus shown in Figure 1. A

For the purpose of I Figure 3 is a cross-sectional view taken along the line 3-3 of Figure 2 when the lower head of the jetting apparatus is positioned against the outer wall of the piling.

Figure 4 is a longitudinal view, taken in cross-section, of an alternative design of a magnetic jetting head which may be secured to the lower end of a pipe string.

Figure 5 is a schematic view illustrating the present magnetic jetting apparatus as it is lowered alongside a steel piling as piling removal operations are in progress.

Referring to Figure l of the drawing, the present mag-v netic jetting apparatus comprises a tubular body member 11 which may be made up of one or more sections of

pipe

12 and 13 connected together by any suitable means, as by a coupling 14. Another coupling or swivel 15 is provided on the top of the uppermost section 12 of the body member 11 for connecting a high pressure hose 16 to the top of the body member 11. Afiixed to the top of the body member 11 or to the upper coupling 15 is a hoop or bail 17 by which the apparatus may be hoisted.

Secured to the lower end of the lowermost section of pipe 13 of the body member 11 are suitable magnet means 20 preferably having a diameter slightly larger than the diameter of the body member 11. In the event that the body member 11 is made of a non-magnetic material, the magnet 2l) may be secured directly to the lower end thereof. Generally, however, the body member 11 is a section of steel pipe, which necessitates the use of a non-magnetic mandrel 21 connected in screwthreaded engagement to the lowermost pipe 13 of the body member 11, as shown in Figure 2 of the drawing. The mandrel 21 has a diameter which is considerably smaller than the diameter o-f the magnet 20 and a length slightly greater than that of the magnet, whereby the mandrel 21 is adapted to extend through the bore 22 of the magnet 20. The reduced diameter section 23 of the mandrel 21 is screw-threaded at its lower-end so as to receive a locking nut 24 which is preferably made of non-magnetic material. If desired, the lower end of the locking or cap nut 24 may be provided with screwthreads or coupling means 25 whereby a drill bit of any suitable design may be secured to the lower end of the apparatus. The bit 26 is provided with one or more Huid ports 27 for discharging therethrough a fluid which is pumped down through the body member 11 of the apparatus.

As shown in Figure 3 of the drawing, the magnetic means 20 secured to the lower end of the apparatus is in the shape of a hollow cylinder having a longitudinal gap 30 cut through the wall thereof. The walls on either side of the gap 30 form the north and south poles of the magnet 20. The magnet 20 is preferably of the permanent type, such as a high-strength alnico-type magnet of high retentivity. If desired, a non-magnetic wear shoe 31 may be secured to the magnet 20 across the gap 30, in any suitable manner, as -by means of screws 32. The outer face of the wear shoe 31 is preferably slightly concave in design with a radius of curvature being substantially equal to that of the steel piling against which the magnet is to be positioned.

Figure 4 illustrates a magnet of different design adapted to be secured to the lower end of a tubular body member 11. From Figure 4 of the drawing, it may be seen that the north and south poles of the drum-shaped magnet 34 are displaced from each other vertically as compared tothe horizontal displacement of the north and south poles of the other magnet 20 (Figure 3). The magnet 34 is provided with an axial hole 35 therethrough which serves as a watercourse for the hydraulic fluid being pumped down through the body member 11. If desired, a short pipe section or coupling 36 of noncopper or stainless steel as magnetic material may be secured between the magnet 34 andthe end ofthe vbody member 11.

Preferably, the gap of the magnet 34 is filled with some non-magnetic material, such as a plastic material 38 which-prevents sand 'or otherforeign substances Kvfrom becoming deposited in the gap. Additionally, Aif desired, the entire magnet base 34 maybe eovered'witha thin sheet 39 of non-magnetic material, such as `brass, shown in Figure 4. `In the event that the :magnet -34 is surrounded by `a sheet of stainless steel, `it is not necessary to 4till the gap between the north and south poles with a plastic material; however, it may be done if so desired.

Referring to Figure k5 of the drawing, the present magnetic jetting tool is illustrated while being employed in the operation of removing a steel piling 33 from the sandy 'bottom 41 below a body of water 42. The operation is carried on from a `barge 43 provided with

suitable hoists

44 and 45. 'Hoist 44 is used to lower the present magnetic jetting tool 11 while the other hoist 45 is used to -pull the piling 33 from the sand 41. The barge or vessel 43 is also provided with a suitable source of pressure iluid, such, for example, as one or

more pumps

46 and 47, whose suction line may comprise a length of hose 48 long enough to reach into .the'water 42. The discharge end ofthe pumps is connected 'by means of a conduit 49 to a hose reel 50 on which a hose 51 is stored. The other end of the hose 51 is in communication with the jetting tool 11 and secured thereto by coupling 15 at the top of the tool.

In operation, the present jetting tool 11 is suspended adjacent the steel piling 33 to be removed so Athat Ythe wear shoe 31 of the magnet 20 is in contact with the other surface of the steel piling 33. Water is sucked into the pumps through in-take line 48 and discharged through conduit 49, hose reel 50 and hose 51 into the Vtop of the tubular body member 11 and thence down through the body member and magnet 20 to be discharged through the lower end of the magnet or through the bit 26 which may be attached to the lower end thereof. As sand is cut away from the side of the steel piling 33, the tubular body 11 and its magnet 20 are lowered by the hoist 44 downwardly along the side of the piling 33, so as to cut away channel 52 in the sand alongside the piling. The weight o the iet tool 11 is suicient to overcome the force of the magnet 20 thus permitting the tool to slide vertically down along the piling 33 while remaining in contact therewith.

Generally, after cutting a single channel S2 down along the side of the piling 33, the earth skin friction against the outer Surface of the piling is reduced Sufficiently so that the piling 33 may be pulled from the sand 41 by the hoist 45. 1f the piling remains rmly Vstuck in the sand after one channel has been cut, one or more additional channels (not shown) may be cut around the periphery of the piling. Alternatively, a drum- Shaped magnet 34 as Shown in Figure 4 of the drawing, may be employed So that the magnet and jetting -end of the tool 11 may be readily rolled around the piling 33 or around a portion thereof,-whereby most or all of the sand surrounding the piling may be rapidly cut out.

The present magnetic jetting apparatus also greatly facilitates the driving of steel pile in unconsolidated earth formations, The present jetting tool is magnetically attached to the lower end of a steel pile and water is pumped through the tool to remove sand from beneath the pile as it is hammered or pushed into the earth. The jetting tool is then pulled to the tnrface when the pile is at its desired depth.

I claim as my invention:

1. A magnetic jetting tool adapted to move along the outer surface of a steel pile for washing unconsolidated sand from around said pile, said tool comprising an elongated tubular body, conduit means connected to the upper end of said tubular body for supplying a stream of hydraulic pressure fluid thereto, downwardly directed fluid port means'atthe lowery end ofsaid tubular body, magnet means carried by said tubular body near said port means for engaging said pile by magnetic attraction, Said magnet means being cylindrical in shape having an axial bore therethrough'and having a circumferential recess in the outer wall thereof intermediate the top and bottom thereof, said recess forming the air gap of said magnet means, and means for lowering said body member vertically along said pile with said magnet means in contact therewith.

2. A magnetic jetting tool adapted to move along the outer surface of a steel pile for washing unconsolidated sandefrom around :said pile, said tool comprising -an elongateditubiilar'bodyyconduitmeans connected-to the upper end of Ysaid tubular body -for supplying `a stream of hydraulic pressure Vlluid thereto, downwardly directed jetting Yoritice Ameans -at'the lower end of said `tubular body, magnet means carried by said l,tubular body near said port means forengaging said pile by magnetic attraction, non-magnetic coupling means Securing said magnet means to said 'tubular body, lsaid magnet means ybeing cylindricaljin Shape'having vanaxial bore therethrough and a longitudinnal slot through `the wall thereof to form the air gap -of vsaid magnet means, and means for lowering said vbody meniber vertically along said pile with said magnet means in contact therewith.

3. A'magnetic jetting tool adapted to move along the outer surface of `a steel pile for washing unconsolidated sand from around said pile, said tool comprising an elongated tubular body, conduit means connected to the upper end vof said tubular body for supplying a stream of hydraulic pressure uid thereto, a drill bit having downwardly directed jetting orifice means, said bit being secured to the lower end of said tubular body, magnet means carried by said tubular body near said port means for engaging said pile by magnetic attraction, saidm'agnet means being cylindrical in shape having an axial bore therethrough and a longitudinal slot through the wall thereof to form 'the air gap of said magnet means, non-'magnetic plate means secured to Said magnet means across said air gap, said plate means having a concave out surface adapted to register with the out wall of said steel pile, and means for lowering said body member vertically along said pile with said magnet means in contact therewith.

4. A magnetic jetting ktool adapted to move along the outer surface of a steel pile for washing unconsolidated sand from aroundsaid pile, said tool comprising an elongated tubular body, conduit means connected to the upper end of said tubular body for Supplying a stream of hydraulic pressure uid thereto, downwardly directed fluid port means at the lower end of said tubular body, magnet means carried by said tubular body near -said portmeans for -engaging said pile by magnetic attraction, said magnet means being cylindrical in Shape having an axial bore therethrough and having a circumferential recess in the outer wall thereof intermediate the top and bottom thereof, said recess forming the air gap of said magnet means, a protective sleeve of thin non-magnetic material surrounding said magnet means and outwardly carried thereby, and means for lowering said body member vertically along said pile with said `magnet means in contact therewith.

'References cited in the sie of this patent UNITED STATES PATENTS Harth Feb. 8,