US2034768A - Method and means of perforating casings - Google Patents

Description

March 24, 1936. F. E. o'NElLL METHOD AND MEANS OF PERFORATING CASINGS 'Filed Feb. 12, 1935 2 Sheets-Sheet l .fia

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)iwf/vrage FRA/vk E. ONE/LL March 24, 1936. F. E, oNElLL METHOD AND MEANS OF PERFORATING CASINGS Filed Feb. 12, 1955 2 Sheets-Sheet 2 Patented Mar. 24, 1936 UNiTED STATES METHOD AND BIEANS F PERFORATING CASINGS 9 Claims.

This invention relates to oil well operations and particularly pertains to a method and means of perforating oil well casing and the like.

When casing has been set in oil wells preparaf, tory to bringing in a producingwell it is, usual practice to perforate the casing adjacent the producing stratum of the earth formation penetrated by the casing. Various methods and mechanisms have been provided for this purpose,

l., including mechanical perforators which expand from the inside of the casing and form holes through the casing wall. These devices are for the most part diicult to operate and do not extend their penetrating action further than the 1;, Wall of the casing. It will be evident that better production of a well can be obtained if the earth formation around the perforations is also opened up to produce a more copious flow of fluid and it is the principal object of the present in- 20 vention to provide a perforating apparatus which will not only perforate the casing but will desirably penetrate the formation.

It is common practice at the present time to maintain the well full of drillingfluid during certain stages of the production of the well, and due to the weight and the character of the drilling fluid there will thus be within the well a column of drilling uid which will produce an enormous hydrostatic head and will create at the bottom of 3U the well an appreciable hydraulic pressure. In

normal well operations this hydraulic pressure will be of the order of one-half pound of pressure per square inch to the running foot of well bore. Heretofore when mechanical perforating 35 devices have been used it has been necessary to manipulate them from the top of the Well. It is another object of the present invention to provide perforating means, either actuated by the available hydraulic pressure, or directly utiliz- .10 ing the pressure fluid to perforate the Well caslng and to penetrate the formation therearound.

The present invention 4contemplates the provision of a perforating structure adapted to be lowered into a well in conjunction with the pack- 4,-, er by which the iiuid column of the well may be 'shut off from the perforating zone, and after which manipulation of the device fromthe top of the hole will `release the pressure of the iluid column into the zone of perforation to create a a perforating action due to said pressure.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a View in longitudinal section showing the control unit to which the perforating unit is attached and by which it is manipulated.

the present invention is concerned.

Fig. 3 is an enlarged view in central vertical section through the preferred form of perforating unit.

Fig. 4 is a view in transverse section through the perforating unit as seen on the line 4 4 of Fig. 2 disclosing the fluid passageway through the packer.

Fig. 5 is a view in transverse section as seen onl the line 5 5 of Fig. 2 disclosing the perforating nozzles and their relation to the iluid passageway.

Referring more particularly to the drawings, I Il indicates a well casing to be perforated by the device with which the present invention is concerned. II indicates a drill pipe adapted to be projected downwardly into the well casing and to carry the perforating structure. This structure comprises two units, the control unit shown in Fig. 1 of the drawings and the perforating unit shown in Fig. 2 of the drawings. The control unit comprises an upper collar I2 threaded at its upper end to receive the drill pipe I I and threaded at its lower end to receive the cylindrical housing I3 of a trip valve M. This valve is formed with a downwardly projecting member I5 at its lower endcarried by a cylindrical body I6. This body may reciprocate vertically within a retainer sleeve 30 Il mounted in the upper end of the housing I3. Radial openings I8 are formed through the wall of the portion I6 and within these openings balls I9 are mounted for radial movement. Disposed within the cylindrical portion I6 of the valve is a 35 plunger 20 which may reciprocate vertically and which is formed with an annular recess ZI adapted at a certain position of movement of the plunger to move downwardly into alignment with the balls I9 and to permit the balls to have inward radial 40 movement. 'Ihe plunger is provided with an enlarged head 22 at its upper end to be struck by a weighted'object dropped downwardly through the drill pipe. The plunger 20, the cylindrical extension I6 of the valve, and the retainer sleeve ll 45 are so designed as to insure that when the plunger is in its uppermost position the balls i9 will be held outwardly to wedge against the lower face of the retainer sleeve Il and to cause the balls to be thus locked in a position to hold the valve structure I4 in its lowermost position. In this lowermost position the extension l5 of the valve rests upon a valve ball 23 which is thus held seated in a closing position over a iiuid passageway 24 formed in end wall 25 of the valve housing f" valve plunger 20.

I3. A spring 26 is disposed between the end wall 25 and a shoulder on the valve structure I4 and tends to urge the entire valve unit to move in an upward direction. Fluid ow ducts 21 are formed radially through the valve structure I4 and communicate with the central bore 28 receiving the A central duct 29'is formed upwardly through the valve plunger to permit uid to flow from the opening 24 through the valve and into the drill pipe II when the valve ball 23 is released from its seat.

A spring collar 30 is secured at the lower end of the valve housing I3 and is also attached to a tubular mandrel 3| which extends downwardly therefrom. The lower end of the tubular mandrel 3| is internally threaded and receives the upper extension of a main valve 32. Slidably mounted on the tubular mandrel adjacent its lower end is a packing box 33 which receives packing 34 and also carries a packing nut 35. The packing nut 35 circumscribes the tubular mandrel 3| and extends into the lower end of the packing box 33 so that the packing 34 may be tightened. The packing box 33 also carries a tubular valve seat 36 which cooperates with the main valve 32 to normally close the lower end of the mandrel 3|. An adjustable tension nut 31 is threaded on to the upper end of the packing box 33 and has an end wall through which the mandrel 3i extends. Interposed between this end wall and the end face of the collar 38 is a helical expansion spring 88 which acts to force the member 38 and the memiber 31 apart so that the valve 32 will rest normall`y upon its valve seat 36. A central passageway 39 is formed through the valve 32 and a plurality of radial uid inlets 40 are formed through the wall of the valve 32 to communicate with the central passageway 39. Thus when the valve 32 has moved to a lower position and is unseated with relation to the valve seat uid may pass upwardly around the valve 32 and into the mandrel 3l culating valve ball 43 on its seat to close the passageway 39 against the upward flow of fluid thereinto, except at such times as excessive uid pressure is created within the drill string II and forces the ball valve downwardly from its seat. Mounted upon the lower end of the packing box 33 and extending downwardly to enclose the main valve 32 and the circulating valve 43 is a cylindrical valve housing 44, the lower end of which is closed save for a central threaded opening 45 into which an equalizing valve mandrel 46 is threaded. This mandrel extends downwardly into the central passageway of an equalizer valve body 41 and terminates in an enlarged head portion 48. A key 49 is interposed between the'mandrel and the valve body 41 so that rotation of the mandrel and the valve body may be eilected in unison. A packing nut 50 circumscribes the mandrel 46 and is adjustably mounted in the upper end of the valve body 41. The packing nut is formed with an annular recess I at its upper end having outlet ducts 52 in communicationy therewith. 'I'he equalizing mandrel 46 is formed with a plurality of radial openings 53 which may be brought to register with the annular passageway 52 when the mandrel is at the upper end of its stroke as limited by the head 48. Mounted at the lower end of the valve body 41 is a bottomV sub 54, which has a lower threaded pin extending into the threaded opening of a valve collar 55 of the perforating unit shown in Fig. 2. The lower end of this valve collar is fitted with an enlarged valve member 56 having a tapered end face adapted to seat against a valve seat 51 under certain conditions, as will be hereinafter described. 'I'he valve collar is mounted on to the upper end of a tubular body member 58 which extends downwardly through a packing unit 59. This unit is here shown as comprising the upper valve seat 51, a plurality of resilient packing rings 68, and a base member 6I. 'I'he base member is formed at its top with a counterbore 62 to receive a sleeve 63 which is circumscribed by the packing ring and which is threaded into the valve seat 51. The lower end of the sleeve is formed with a collar which limits its upward movement. A bore 64 extends downwardly from the counterbore and within the base 6I. This bore is of a materially larger diameter than the tubular body member 58 which extends through it. Below the bore 64 a reduced bore 65 occurs which is of substantially the same diameter as that of the tubular body 58, and forms a sliding fit therewith. A packing gland 66 is carried at the lower end of the base 6I and around the body 58. Attached to the lower extension of the base 6I and threaded therewith is an expansion cone 61 around which a plurality of slips 68 are arranged. These slips are carried upon reins 69 pivoted to a slip rein collar mounted at the upper end of a tubular cage 1 I. The body 58 telescopes through the tubular cage and carries a seating pin 12 which moves in a bayonet slot 13 to lock the cage 1I in position upon the body 58. 'I'he cage carries a plurality of bow-shaped anchor springs 14 which may engage the inner face of a casing within which the device is being used. 'I'he body 58 ex-I tends downwardly through the cage and carries a coupling at its lower end which coupling in turn receives a perforated nipple 16 through which fluid may pass upwardly into the body 58 in a manner to be hereinafter described.

At a point in the length of the base 6I within which the bore 64 occurs a plurality of perforating nozzles 11 are mounted. 'Ihese nozzles are disposed within threaded radial bores 18. Each nozzle comprises an outer threaded sleeve 19 mounted within the bore 18 and having a shoulder 80 at the inner end of the bore, and a nozzle tip 8| slidable within member 19 and yieldably held in a retracted position by spring 8|', and through which nozzle uid may be projected from the bore A64 outwardly against a surrounding casing as the nozzle is forced outwardly to form a perforation as indicated at 82 in Fig. 3 of the drawings. A .uid circulating valve 84 is mounted through the wall of the base 6I and controls communication of fluid into the bore 64. The circulation valve structure 84 comprises a valve ball 85 adapted to rest against a removable valve seat 86 and held against this seat by a spring 81. Circulation openings 88 Vare formed through the valve head 56 of the valve collar 55 for a purpose to be hereinafter described.

In operation ofthe present invention the control unit as shown in Fig. 1 and the peri'orating unit as shown in Fig. 2, are assembled with the control unit `uppermost .and this structure is then mounted at 'the lower end of the drill pipe II to be inserted into the well. When the control unit is ready for insertion care must be taken to insure that the trip valve structure I4 shall be locked so that the valve ball 23 will be held Vrmly on its seat over the opening 24. In this position it will be recognized that the drill stem Il will be sealed o from the fluid which will be penetrated as the tool is lowered into the hole. At

' the same time the spring 38 holds the mandrel 3| and the circulating valve housing 34 in a position to maintain the main valve l32 -on its seat 36. The perforating unit is held in its locked position by the engagement of the lock pin 12 with the slot 13, at which time the slips 68 will be held in their lowermost position and the valve seat 51 will be held in its lowermost position and out of engagement with the valve member 56. As the entire assembledstructure is lowered into the well the fluid present in the well may flow upwardly through the perforating nipples 16 into the body 58 of the perforating unit and then upwardly through the equalizing mandrel 46 and into the housing structure 44 where further upward ow of the fluid will be Y,

stopped by the valve 32 which is held in a closed position upon the seat 36 by the spring 38. If accidental movement of the member 44 occurs due to the fact that the perforating unit encounters an obstruction which prevents or retards its downward movement sufficiently 'to overcome the expansive action of the spring 38, or if the pressure of the fluids within the well should be sufficient to overcome the tension of the spring 38 the valve 32 might open and permit uid to enter the tubular mandrel 3|. 'I'he further upward ow of uid would, however, be prevented due to the fact that the valve ball 23 is locked on to its seat by the trip valve mechanism I4. Thus the upward limit of ow of uid within the tool prior to the time the trip valve I4 is opened would be to this trip valve. It will be recognized that as the device is lowered into the well through the fluid it is necessary for the fluid to be bypassed through the packer. This is accomplished by the pressure of the fluid which lifts the valve ball 85 from its seat 86 and allows iiuid to pass upwardly into the space 64 of the base 6I of the packer. This fluid will then pass upwardly through the member 63 and outwardly into the well casing I through the valve seat 51. Due to this arrangement there will be no difficulty in lowering the device into the well through the drilling fluid. When the device is at the position where perforations are E be made the drill stem II is manipulated so to disengage the pin 12 carried on the body 58 from the hooked upper portion of the slot 13, thus permitting the body 58 to move downwardly while the cage 1I is frictionally held by engagement with the casing wall. As the body 58 moves downwardly the cone 61 will force the slips 68 outwardly to positively grip the wall and to prevent further downward movement of the structure which includes the cone 61,v the base 6I and the packer 59. When thepacker is thus moved to its limiting position the valve collar` 55 and the valve 56 will move downwardly so that the valve 56 engages the valve seat 51 and exerts pressure to deform and distend the packing rings 63 and to cause them to expand into the casing I8 and to seal .ofi all of the fluid column above the packing from the area of the casing below the packing. After the valve 56 has been thus set it will be evident that the valve 85 will be moved on to its seat to close the opening through they valve seat 84 and t0 prevent downward iiow of uid from the passageway 64.. When the packer has been set as previously described a periorating operation lished a flow of uid may be subsequently per-' mitted by dropping a. Weighted instrument, commonly called a go-devil, down through the drill pipe II until it strikes the head 22 of the plunger 20. At such a time the plunger will be moved downwardly to bring the annular recess 2l which is formed around its body into register with the balls I8, thus permitting them to move inwardly to a point of clearance and to allow the expansive action of spring 26 to move the valve element I6 upwardly so that the upward pressure of the fluid against valve 23 will lift it from its seat. The fluid from the well may then flow upwardly into the drill stem through the radial passageways 21 and the central passageway 28 of the member I6 and through the central pasin the casing, both above and below the packing,

Will at this time be quiescent since the valves 32 and 23 are closed and prevent an upward circulation of the fluid of the well into the drill pipe which pipe is empty and is under normal atmospheric pressure. When it is desired to make the initial set of perforations in a well casing a godevil is dropped down through the drill stem to strike the head 22 of the plunger 20 forming a part of the trip valve unit I4. Since the valve 32 has been previously opened the opening of the trip valve I4 will permit fluid to surge upwardly into the empty drill stem II and as the fluid which is within the portion of the casing I 8 below the packer is forced upwardly the fluid in the casing I0 above the packer will be forced downwardly under its weight and pressure. This iiuid will pass through the ducts 88 inthe valve 56, thence through the sleeve 63 to the space 64 and then outwardly through the nozzle 11 under the pressure of the head of the column of fluid and at a high velocity. As the uid forces its way outwardly through the nozzle tip it will also force the nozzle tip outwardly into close proximity to the casing wall. This will ensure that the uid will be delivered directly to the surface to be abraided. The fluid will act by abrasion to cut perforations throughahe casing and will also act to penetrate formation through which the casing extends. The spent uid will then flow downwardly on the opposite side of the casing or within it and find its way into the perforated nipple and thereafter will flow upwardly into the drill stem.

In the event it is desired to form other perforation operations the weight o'f the drill stem may be relieved from the perforating unit and the drill stem with the valve 32 may be drawn upwardly as the spring 38 expands so that the valve 32 will engage the seat 36. By this operation the upward fluid flow into the drill stem may be interrupted, after which the structure may be further raised to relieve the pressure of the valve 56 from the valve seat 51 so that the packer may be released and moved to a different level than the casing. When the packer is again set by imposing pressure on the packer and expanding cone to force the slips into a setting position a further lowering of the drill stem will move the valve 32 from its seat and permit an upward surge of'iluid to again take place into the drill stem accompanied by a downward surge of iiuid from the column above the packer and outwardly through the nozzles 11 to form another perforating operation. This operation may be repeated so long as there is a suicient diierence in pressure between the column of iiuid within the casing andthe column of uid within the drill stem. It Will be evident, however, that eventually the two columns of fluid will equalize each other as to pressure, at which time it will be necessary to elevate the entire tool,

drain and drill stem, and renew the cycle of operations if desired. When the device is to be withdrawn from the well it may be necessary to insure that there is no swabbing action of the packer, and particularly if the device is withdrawn before the uid columns within the drill stem and the casing become equalized. For that reason the equalizing valve structure has been provided which will cause the ducts 53 in the equalizing mandrel 4B to move into register with the annular space 5I of the packing nut 50 and will permit uid to pass through the opening 52 so that the pressure will be equalized through the ltool as it is withdrawn.

. The invention as here disclosed has been concerned with the direct perforation of a well casing by the abrasive action of a high velocity stream of liquid caused to flow by the control of valve means associated with the device.

It will thus be seen that by the operation of the device here shown it is possible to perforate a casing by utilizing the pressure and abrasive action of the column of uid present within the casing at the time the perforating operation is carried out, and to insure that this operation may be easily brought about by the simple manipulation of the drill stem from the top of thewell.

While I have shown the preferred form of my invention, as now known to me, it will be understood that various changes might be made in the combination, construction, and arrangement of parts, by those skilled in the art, Without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A method of perforatlng a Well casing at the bottom of a well which consists in lowering a device into the well and submerging the same within the column of liquid present Within the well, thereafter packing oil? the column of liquid within the well, and then establishing communication between a casing perforator responsive to iiuid flow and a compartment at reduced pressure whereby uid from -the column within the well may pass downwardly through the casing perforator responsive to iluid iiow and to cause actuation of the same.

2. A method-of perforating a wellv casing within which well a column of fluid stands, which method consists in introducing a perforating nozzle intov the well and submerging it within the fluid, thereafter shutting off the column of uid within the well to establish a fluid head and then establishing communication between said uid column and an area of reduced pressure from a point below the perforating nozzle whereby a flow of uid will be established from the column through the point of shut off and the perforating nozzle and thence into a column under reduced pressure.

3. A method of perforating a well casing within which casing a column of liquid stands, which method consists in'introducing a closed conduit into the well and submerging the same within the iluid, said conduit carrying a packer, a perforating nozzle and a valve adjacent its lower end, thereafter setting the packerto establish a denite liquid head within the casing, then opening the Valve to release the fluid below the packer, whereby the liquid in the column above the packer will flow downwardly and outwardly through the perforating nozzles to impinge against the casing wall and will then iiow upwardly through the valve and into the drill stem.

4. A device of the class described comprising a drill stern adapted to be lowered into a well con-- taining liquid, a packer carried by the drill stem adjacent its lower end, a nozzle carried by the drill stem at a point below the packer and in vcommunication with the column of fluid within the well and above the packer, and a valve in the drill stem adjacent its lower end whereby when the valve is openedliquid from the column above the packer may pass outwardly through the nozzle below the packer and then pass upwardly through the valve and into the drill stem.

5. A well casing perforator comprising a drill pipe adapted to be lowered into a well casing containing drilling iiuid, a packer carried on the drill pipe adjacent the lower end thereof, said pipe having a passageway through the packer, a valve adjacent the lower end ofl the drill pipe and adapted to be operated from above ground, to establish and interrupt communication between the Well and the pipe, and a perforating device carried by the pipe at a point below the packer and being in constant communication with the liquid in the well above the packer whereby when the valve is opened a downward flow of liquid from above the packer and through the perforating device may take place, after which said liquid may ilow upwardly through the Vopen valve and into the drill stem.

6. A Well casing perforator comprising a drill pipe adapted to be lowered into a well casing containing drilling iiuid, a packer `carried on the drill pipe adjacent the lower end thereof, said pipe having a passageway through the packer, a valve adjacent the lower end of the drill pipe and adapted to be operated from above ground. to establish and interrupt communication between the well and the pipe, a perforating device carried by the pipe` at a point below the packer and being in constant communication With the liquid in the well above -the packer whereby when the valve is opened a downward flow of liquid from above the packer and through the perforating device may take place,. after which said liquid 'may flow upwardly through the open valve and into the drill stem, and an equalizer valve normally closed and adapted toopen when the device is withdrawn from a well to break the fluid seal around the packer.

7. A casing perforating tool adapted to be inserted into a Well which is lled with drilling fluid, which tool comprises a tubular member extending down into the well to a pointbelow the area of the casing to be perforated, a packer through which said tubing extends, said packer including means to set the same at a desired position within the well, a perforating nozzle carried below the packer and communicating with a fluid bypass through the packer and exteriorly of the tubular member, valve means within the tubular member and adapted to be manipulated to establish and interrupt a ow of fluid from the portion of the well below the packer upwardly into the tubular member, and a second valve disposed within the tubular member at a point above the`rst named valve, said second valve being closed normally and being adapt-V ed to be. opened independently of the rst named valve.

8. A casing perforating tool adapted to be inserted into a Well which is filled with drilling uid, which tool comprises a tubular member .extending down into the well to a point below the area of the casing to be perforated, a packer through which said tubing extends, said packer including means to set the same at a desired position within the w'ell, a perforating nozzle carried below the packer and communicating with a uid bypass through the packer and exteriorly of the tubular member, valve means within the tubular member and adapted to be manipulated to established and interrupt a flow of fluid from the portion of the Well below the packer upwardly into the tubular member, a second valve disposed within the tubular member at a point above the rst named valve, said second valve being closed normally and being adapted to be opened independently of the rst named valve, and an equal- 5 izer valve disposed in the tubular member and adapted to permit a flow of `uid through the portion of the tubular member which extends through the packer when the device is being withdrawn from the well. 10

9. A method of perforating e casing of an oil well lled with drilling fl which consists in lowering a uid flow responsive device into the Well and submerging the same in the column of liquid standing in the well, thereafter packing 15 said uid against the casing wall to abrade and perforate the same.

FRANK E. ONEILL. 25

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