US1919350A - Oil well cleaning device - Google Patents

Description

July 25, 1933. N. w. WICKERSHAM OIL W ELL CLEANING DEVICE Filed July 14, 1931 Patented July 25, 1933 UNITED STATES NEWTON W. WICKEBSHAM, 0]? LOS ANGELES, CALIFORNIA, ASSIGNOR, BY MFJSNE PATENT OFFICE ASSIGNMENTS, TO YOWELL 8:; YARBROUGH, INC., 0] LOS ANGELES, CALIFORNIA,

A CORPORATION OF CALIFORNIA f OIL WELL CLEANING DEVICE Application filed July 14,

This invention relates tooil well appliancesand tools, and particularly to devices for clezltlmng perforated pipe or screening in a we Various types of devices have been used 1n the past for cleaning perforated casings and screens in oil wells. These perforated casings and screenings tend to become clogged. with sand and other detritus that is packed against the outside of the casing by the natural flow of oil into the casing through the perforations. One of the most successful methods of cleaning casing that has become-clogged inthis manner is to insert two plungers within the casing and reciprocate one of the plungers relative to the other, thereby forcing oil trapped between the plunger out through the perforations in the casing.

A device of this type is disclosed in United States patent to L. McGregor, 1,802,612, issued April 28, 1931. This device comprises an upper packing device rigidly attached toa shaft which is lowered into the well, and a lower packing deviceslidably mounted on the shaft. The lower packing device has slips associated therewith for looking it in the casing at a desired point. Thereafter the shaft and upper packing member are reciprocated toward and away from the lower packing member, thus forcing oil out through the perforations in the casing each time the upper packing member is forced down against the lower packing member. Although remarkably successful in many ways, the device of the McGregor patent has the followingobjectionable features: First, when lowering the device into a well in which the casing is bent or broken, the slips attached to the lower packing member some times become wedged in the broken or bent casing and are either damaged or jammed so that they cannot be dislodged and withdrawn; second, the lower end of the shaft on which the packing members are mounted is open at the bottom, and this some times permits the entry of mud into the shaft as it is approaching the bottom of the well, thus clogging the opening in the shaft; third, the slips are locked in retracted position,

while 1931. Serial No. 550,682.

I the device is being lowered into the well by a lock which, after being once released, cannot again be locked while the device is within the L well.

An object of this invention is to improve the reliability and efficiency of well cleaners of the type described.

A particular 01)]6Ct is to provide a well cleaning device that can not readily stick or jam while it is being lowered through a cracked, bent or broken casing.

Another object of the invention is to provide a lock in a well cleaning device for maintaining the device in retracted position while it is being lowered into or withdrawn from the. well, the lock being so designed that it will not release accidentally, but may be readily released or locked at will by the operator, while the device is in the Well.

Other objects and advantages of the invention will be apparent from the following description, taken in connection with the accompanying drawing, in which Fig. 1 is an elevational view of my cleaner as it would appear in a casing, the casing being shown in section.

Fig. 2 is an enlarged elevational section of a cleaner in accordance with my invention, some of the elements shown in Fig. 1 being omitted to simplify the drawing.

Figs. 3, 4 and 5 are diagrammatic views showing my cleaner 1n various phases of its operation.

Referring to Figs. 1 and 2, myvdevice comrises a central shaft 1 adapted to beattached to the end of a hollow drill rod (not shown) and thereby lowered 1nto or wlthdrawn from a well. Shaft 1 is enlarged at its upper portion and carries one or more packing elements 2. Below these packing elements the shaft is shown reduced in size 1n the particular model shown. However, this reduction in size is not essential, the only necessary feature being that the lower part of the shaft be smooth and straight on 1ts outer surface to permit the lower pack ng assembly (to be described later) to slide freely thereon.

The lower "packing assembly comprises a packing member 3, a plurality of slips 4, and

a locking mechanism designated generally at 5, all mounted on a sleeve 6 which is slidably supported on the smooth lower portion of the shaft 1. Both the upper and lower packing members 2 and 3, respectively, are preferably constructed of rubber and are provided with outer reinforcing wires 7 to prevent the rubber being torn or ruptured. The reinforcing wires 7 extend over the free edge of each packing member 2 and 3 and are secured together at their free ends by rings 8. Since the use of reinforcing wires over packing members in the manner described is old, and the structure is sufficiently disclosed in Fig. 1, these wires have been removed from the sectional view of Fig. 2, to simplify the drawing. It will be noted that the upper packing members 2 are cupped on their under sides and the lower packing member 3 is cupped or concave on its upper side so that while the packingmembers are being separated, the liquid pressure on the outside can force the packing members inward, thus permitting liquid to escape around the edges of the packingqdevices into the space 9 therebetween. owever, when the upper and lower packing members are forced together, the hydrostatic pressure between the packing members forces them out tightly against the casing so that substantially no leakage between the packing members and the casing can take place.

During the cleaning operation, the lower packing member 3 is secured to the casing by expanding slips 4, which are mounted on tapered faces 10 on the lower packing member 3. Slips 4 are attached by members 11 at their lower ends to a ring 12 which surrounds and is rotatably attached to a collar 13 slidably mounted on sleeve 6. Collar 13 is attached to the upper ends of a plurality of bowed spring members 14 which normally bend outward and engage the casing 15 of the well. Spring members 14 are attached at their lower ends to a collar 16 which, like collar 13, is loosely mounted on sleeve 6.

Collar 16 is provided with a spiral slot 17 extending upward from the lower edge thereof, and a pm 18, projecting from sleeve 6,

' normally engages the slot 17 and thus pre vents the collar 18 from moving longitudinally with respect to sleeve 6. As shown in Fig. 1, the lower edge of slot 17 is cut out at theend thereof so that when pin 18 approaches the end of the slot it drops into the groove and tends-to remain in locked position. To further reduce the possibility of pin 18 being dislodged by vibration, or accidental movement, from the end of the slot 17, a spring 19 and a collar 20 are provided on the lower end of sleeve 6 between collar 16 and the enlarged end 21 of the sleeve 6.

When the pin 18 is in the end of slot 7, spring 19 hearing against shoulder 21 on the end of sleeve 6, forces collar 20 against the lower edge of collar 16, thus tending to force the collar 16 up until the pin 18 seats in the pocket in the end of slot 17.

When pin 18 is engaged in the end of slot 17, collar 16 is retained in its lowermost position with respect to sleeve 6 and this maintains the slips 4, which are connected to collar 16 by members 14 and 11, at the lower ends of the tapered seats 10. In this position, the slips 4 are retracted sufficiently so that they do not engage the casing 15 and the entire device may be readily lowered therethrough. On the other hand, when sleeve 6 is turned to the right with respect to collar 16, pin 16 disengages from slot 17, thus permitting collar 16, members 14, collar 13, ring 12, members 11 and slips 4 to move upwardly with respect to sleeve 6 and the tapered seats 10. Movement of slips 4 upward along tapered surfaces 10 forces the slips outward into engagement with the casing 15.

To prevent the slips 4 from becoming wedged or broken in a jammed casing, while the device is being lowered therethrough, an enlarged head 22 is provided on the lower end of shaft 1. This head will be blocked by any bend or distortion in the casing sufficie'nt to catch the slips 4. Head 22 is provided with lateral passages 23 connecting with the central bore 24 of shaft 1 and there is no opening through the bottom of head 22.

The lower end 21 of sleeve 6 has a splitaway portion forming a pair of shoulders 25 and the upper side of the head 22 on shaft 1 is likewise cut away to form shoulders 26 so that by withdrawing shaft 1 the shoulders 26 on head 22 may be brought against shoulders 25 on the end 21 of sleeve 6, whereby sleeve'6 and pin 18 may be rotated with respect to collar 16 to lock or unlock the slips.

The combined frictional resistance of members 14 and the lower packing member 3 against the casing, causes these members, together with sleeve 6, to ride up on the shaft 1, when the latter is lowered through the casing, until the top of sleeve 6 abutts against the enlarged portion of shaft 1 immediately below the upper packing member 2, as shown in Fig. 3. Hence, packing members 2 and 3 and the slip mechanism are close together and the shaft 1, with its enlarged head 22, projects some distance ahead. This is advantageous, since, should the casing be bent, dented, or distorted in any way sufficiently to engage slips 4, the entire device will be stopped by the head 22 encountering the distorted casing. The operator can then withdraw the entire device from the casing without having it damaged in any way. On the other hand, if the enlarged head 22 were not provided on the lower end of shaft 1, the device would pass freely down through the casing until slips 4 were opposite the distorted part of the casing. When this happened, one of the slips 4 would probably be torn away from its seat 10', or else the entire slip mechanism would be jammed in the casing so that it could not be pulled loose without damaging it..

When the device has been lowered to the portion of the casing which it is desired to clean, the shaft 1 is withdrawn throu h sleeve 6 until the shoulder 22 lies agains the lower end 21 of sleeve 6. During this upward movement of shaft 1 and the packing members 2 attached to it, the sleeve 6 is maintained in stationary position in the casing due to the friction of the packing member 3 and of the bowed members 14 against the casing. When shaft 1 has been withdrawn, as described, until the head 22 lies against the end 21,.of the sleeve 6, the shaft 1 is turned to the right until one of the shoulders 26 abuts one of the shoulders 25 and turns sleeve 6 and pin 18 with respect to collar 16, collar 16 being free to rotate about sleeve 6 and tending to remain stationary because of the frictional resistance between the bowed members 14 and the casing 15. Sleeve 6, pin 18 are therefore turned with respect to collar 16 until pin 18 is released from slot 17 and the apparatus is in the position shown in Fig. 4.

After retracting and rotating the shaft 1 as outlined to release the pin 18 from slot 17 the operator lowers the shaft 1 in the casing. When shaft 1, together with packing members 2 was raised, the excess hydrostatic pressure above packing members 2 and below packing member 3 forced oil past those members so that the space below packing members 2 and above packing member 3 in Fig. 4 filled with oil. Therefore when shaft 1 and packing members 2 are subse quently forced downward they tend to compress this oil and the increased pressure of the oil forces the lower packing member 3 downward. Packing member 3 being attached to sleeve 6, the sleeve is also forced downwardly, but since pin 18, in the sleeve is no longer engaged with slot 17, in collar 16, the assembly comprising collar 16, collar- 13 and slips 4 is free to slide upward on sleeve 6. Furthermore spring members 14, being bowed outward against the casing 15, tend to remain stationary as the sleeve 6 is forced downwardly by the hydrostatic pressure above packing member 3. Therefore the tapered surfaces 10 force the slips 4 out into engagementwith the casing 15, as shown in Fig. ,5.

The outward force exerted by the slips 4 upon the casing 15 is proportionate to he downward pressure exerted on the slip gui es 10 by the packing member 3. Therefore, after the slips have been set, the lower packing member 3 -is prevented from moving downwardly within the casing and as the upper packing members 2, together with shaft 1 are moved downward, they force the oil between the packing members 2 and 3 out through the perforations in the casing, thus cleaning the perforations.

The upper packing members 2 may 'be reoiprocated up and down several times with the lower packing members in the same position, to thoroughly clean the perforations. Thereafter the entire device may be raised to a position higher in the casing, and the 21 of the sleeve 6. The shaft 1 is then turned to the left until the shoulder 26 on head 22 engages with shoulder 25 on the end of sleeve 6; then continued turning ofshaft 1 turns the sleeve 6 and rotates the pin 18 up into the slot 17, whereit locks. As already pointed out, when pin 18 is locked in slot 17, the slips 4 are held on the lower part of the guide 10 so that they cannot ride up on theguides 10 and be forced into locking engagement with the casing.

As already described, when the shaft 1 and the upper packing members 2 are separated from the packing member 3, the excess hydrostatic pressure above packing members 2 and below packing members 3 forces those members inwardly from the wall of the casing to permit oil to flow past them into the space between the packing members. However, since the packing members 2 and 3 are rather stiff and do not always yield readily to admit oil to the space therebetween, I have found it advantageous to provide valve openings between the passage in shaft 1 and the space immediately below the packing members 2. Thus, referring to Fig. 2, openings 27 are provided in the wall of shaft 1 and these openings are covered with 7 spring flaps 28. Whenever the pressure in the casing between the'packing members 2 and 3 is in excess of the pressure below the packing member 3, the flexible flaps 28 are forced against shaft 1, thus sealing the openings 27. However, as shaft 1 and upper packing member 2 is withdrawn, the pressure in the space below the packing member 2 is reduced below the pressure of the liquid in the casing below the cleaning device, and

in the passage within shaft 1 which is iIb communication therewith through the openlugs 23 in the slot 22. This excess pressure within shaft 1, therefore, forces the flaps 28 casing, a hollow shaft, pac (ing means fixedvalve in the wall of said hollow shaft positioned between said first and second packing members for supplying fluid from said hollow shaft to the space between said packilng means but preventing a reverse flow of uid.

NEWTON W. WICKERSHAM.

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