Well Cleaner

Abstract

A device for cleaning and/or disinfecting commercial wells consisting of a tubular housing smaller in diameter than the well casing and which is lowered to a location below the liquid level in the well. A resonant diaphragm partition separates the housing into an upper closed chamber and a lower open chamber. Centrally mounted on the upper portion of the diaphragm is a rotational mass which revolves at constant speed and the mass-speed relationship develops sinusoidal vibrations in the low-sonic range and substantially vertical to its diaphragm mount location. The sinusoidal force excites the diaphragm into one of its modes of natural frequency in the form of bending wave motion in the diaphragm. The force, sinusoidal in nature, thus released also excites the housing of the upper and lower chambers and longitudinal bending waves are in turn continuously developed and transmitted through the material of the housing and in a direction through the lower open end portion of the cylindrical housing. The longitudinal bending wave vibrations in the material of the cylindrical housing in turn cause compressional acoustic waves to be transmitted through the surrounding water medium at speeds approximating 4,800 feet per second from both the inner and outer surfaces of the lower open end cylindrical shell, and from the outer surface of the upper closed cylindrical shell. The direction of the released compressional sound waves is perpendicular to surfaces of the cylindrical shell and the waves are multidirectional in nature.

Description

It is well known to the state of the art that a structure can be so designed, with materials of known modulus, dimensions and configurations that have known moments of inertia, and that in combination with specific mass densities the structural natural frequency and modes can be predetermined and be resonant with any discreet frequency. In this instance the structure is designed to be at its maximum efficiency for its defined purpose in that it is resonant and its transmissibility and amplification of sonic energy generated in the form of sound waves is at a maximum.

It is well known in the art that all liquids have resonant frequency bands. The subject structure is designed to be resonant with its input frequency and is at its maximum efficiency in terms of output to input. The resulting transmissibility of sonic energy compressional sound waves excites, resonates and causes cavitation with the fluid in the well surrounding and adjacent the device.

The cleaning action of the sonic energy device is based to a major extent on the phenomenon called cavitation. The implosion of minute cavities or bubbles which are produced by pressure differentials imposed within the solution at the inner well surface and areas of well incrustation account for the cavitation.

The cleaning and/or disinfecting capability of the device is further enhanced by means of release of acid chemicals, such as chlorine gas, to the solution within the lower shell of the device. Such chemicals are forced by mechanical and cavitational energy through the holes in the lower shell to the pipe surface to be cleaned and are subjected to intense cavitational energy at the well surface and throughout the incrusted areas in the presence of well water to increase the rate of cleaning or disinfecting, as the case may be. Acid chemicals or chlorine gas, when injected into the water area, cause a foaming solution and the bubbles of the solution are caused to alternately expand and to collapse and to leave a void or hole in the foam solution when subjected to the action of the compressional sound waves. The foam solution rushes to fill the void or vacuum, creating tremendous transitory vacuums and alternative pressures. The alternate vacuum and pressure action of the sound waves constitute the major aspect of a properly designed and efficient sonic energy cleaning system.

Among the objects of the invention is to provide a new and improved cleaner for wells which is very penetrating in its effect upon the walls of the liner and casing, as well as in the adjacent formation, but which is not drastic in its performance so that there is no prospect of damage to the liner or casing or the future ability of the well to produce.

Still another object of the invention is to provide a new and improved well cleaning apparatus which can be lowered easily and inexpensively into a well needing cleaning and set in operation upon reaching the precisely desired depth and which, moreover, can be shifted throughout an appreciable vertical distance on those occasions where the producing strata is many times thicker than the length of the apparatus so that with only a single drop of the apparatus into the well all portions of the liner needing cleaning can be cleaned before the apparatus is removed.

Still another object of the invention is to provide a new and improved well cleaner operating on the vibration principle in which can be incorporated a chlorinating device or other type of liquid dispenser which can be operated simultaneously with the cleaning operation and which is caused to more effectively perform its work in the well by reason of the vibration energy present for the cleaning operation.

Still another object of the invention is to provide a new and improved method for cleaning wells which makes use of vibration energy in the low sonic range so that the vibration energy after being generated in the apparatus is caused to travel through the liquid in the well to the surrounding liner and producing formation thereby making use of vibration for cleaning and also treating in such fashion that there is no likelihood of damage resulting to the well.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a longitudinal sectional view of a typical well showing the well cleaner lowered to a location below the top of the liquid level near the bottom of the well.

FIG. 2 is a longitudinal sectional view showing the interior construction of the apparatus.

FIG. 3 is a longitudinal sectional view on the line 3--3 to FIG. 2.

FIG. 4 is a cross sectional view on the line 4--4 of FIG. 2.

FIG. 5 is a fragmentary longitudinal sectional view on the circular line 5 of FIG. 3.

FIG. 6 is a fragmentary longitudinal sectional view on the line 6--6 of FIG. 2.

FIG. 7 is a longitudinal sectional view of the housing for the cleaning apparatus in one mode of vibration.

FIG. 8 is a view similar to FIG. 7 wherein the apparatus is in another mode of vibration.

FIG. 9 is a cross sectional view on the line 9--9 of FIG. 7.

FIG. 10 is a longitudinal sectional view of another form of the device.

FIG. 11 is a cross sectional view on the line 11--11 of FIG. 10.

FIG. 12 is a cross-sectional view on the line 12--

In an embodiment of the invention chosen for the purpose of illustration there is shown a well 10, extending down from the earth surface 11, and provided with a casing 12, which extends to the producing strata where the casing is provided with a perforated liner 13. Production fluid which may be water or petroleum as the case may be flows through the perforated liner into the bottom of the well where it stands as a reservoir of fluid 14. A housing 15, containing appropriate cleaning apparatus is suspended in well 10, by means of an electrical supporting cable 16. The cable is wound on a power-driven reel 17 and paid out over pulleys 18, at the end of adjusting arm 19. Additional pulleys 20, forming part of well head assembly 21, anchored to the top of the casing 12, center the line in the well as the housing 15, is moved up or down as the case may be.

The housing 15, in the embodiment shown is cylindrical and has a diameter substantially less than the inside diameter of the casing 12, so that the housing can pass freely down into the well until its work has been performed and can then be withdrawn therefrom with sufficient ease so that this can be accomplished even though the casing may not be perfectly straight as is frequently the case in actual practice. Rubber buttons 22 are provided to serve as bumpers to make certain that the housing clears the surface of the casing on all sides.

Within the housing 15 is a partition 25 the center portion of which is a stiff, flexible diaphragm 26 which separates the interior of the housing into an upper closed chamber 27 and a lower open chamber 28.

A bracket 30 is secured to a boss 31 which is located at the center of the diaphragm 26, and secured thereto by means of bolts 32. The bracket supports a motor 33, at opposite ends 34 and 35. The mountings for the motor on the bracket at opposite ends differ materially although both serve as a means for holding the motor in operating position.

At the end 34 a drive shaft 36 from the motor extends into a bushing 37, as shown in FIG. 6, wherein it is secured in place by means of a set screw 38 on an axis 39 eccentric with respect to the axis 40 of a stub shaft 41 forming part of the bushing 37. A bearing ring 42 rotatably mounts the stub shaft 41 at one end 43 of the bracket 30. From the foregoing description it will be apparent that in the embodiment of the invention illustrated in FIGS. 1, 2, and 3, that the left end of the motor 33 is eccentrically mounted and when the drive shaft 36 is rotated by operation of the motor, the mass of the motor will rotate cyclically about the axis 40 of the resilient bearing mount thereby developing and transmitting a sinusoidal force motion to bracket 30 at its end 43 through the stub shaft 41.

At the end 35 of the casing of the motor 33, namely the end opposite to that just described, there is a motor flange 45 bolted to a motor frame 46 of the motor 33 by means of bolts 47 as shown in FIG. 5. A stub shaft 48 extending outwardly from the base 45 is received in a resilient bearing assembly indicated generally by the reference character 49. The bearing assembly in turn is anchored to another end 50 of the bracket 30 by means of screws 51.

In the embodiment shown in FIG. 5 there is a bearing sleeve 52 forming a bearing within which the stub shaft 48 is anchored in a stationary position by means of a pressed fit. Around the bearing sleeve is an annular resilient and vibration absorbing pad 53 which is held in position by a retaining sleeve. A sleeve bearing 56 is press fitted and anchored to retaining sleeve 54. Sleeve bearing 56 is housed in a sliding fit to a bearing 58 which is anchored to the bracket end 50. A disc plate 55 is provided to fasten the bearing assembly in position by means of screws 51 and 57.

What is important for the mounting of the end 35 of the motor is that a substantial portion of the vibration which is set up in the motor mass by eccentric mounting at the opposite end 34 is prohibited from passing from the motor to the end 50, thereby making it necessary that essentially all of the vibration travel through only the other end 43 of the bracket and then to a single connection between the bracket 30 and the diaphragm 26 at the location of the boss 31.

An electric cable 60 connected to the motor extends upwardly through a fitting 61 threadedly mounted at the center of a closure 62 for the upper end of the closed chamber 27. Hand holds 63 and 64 may be provided on the closure to facilitate handling when the apparatus is not in a condition of operation in the well.

For ease in manufacture an upper section 65 of the housing, is made separate and adopted to threadedly engage the partition 25 at the lower end. Similarly a lower section 66 of the housing is adapted to threadedly engage the partition 25 and has its entire lower end open as indicated by the reference character 67 as shown in FIGS. 2, 7, and 8.

In the embodiment described the lower section 66 may be of relatively lighter gage than the upper section 65 so that it has greater freedom to flex.

In operation of the device constructed as described the housing 15 is lowered into a well 10 to a location within the reservoir 14 of production fluid, preferably below its upper surface 68. Holes 69 extending through the lower section 66 and the open lower end 67 permit fluid to pass freely into the lower open chamber 28 to a location adjacent the underside of the partition 25.

Inasmuch as the upper chamber 27 is a closed chamber no fluid is permitted to enter it and the chamber serves to provide buoyancy for the apparatus when it is submerged in production fluid 14. This is particularly helpful in deep wells where the weight of a long length of line 16 adds appreciably to the weight of the apparatus in the well which must be supported by the upper end of the line.

After the housing has been lowered to its location within the production fluid, the lowering operation is halted and power turned on to set the motor 33 in operation. The rate of rotation of the drive shaft 36 is synchronous as provided in this case by an AC induction motor and good operating conditions are experienced by design when the drive shaft rotates at a frequency in the low sonic region. Amplitude of the force motion vibrations set up in the diaphragm 26, by the eccentric mounting described in connection with FIG. 6 is controllable by the relationship between the axis 39 of the drive shaft and the axis 40 of the stub shaft, this being the degree of eccentricity of the drive shaft mounting.

By reason of the motor mountings described the sinusoidal force excitation is concentrated at the center of the diaphragm 26. Vibratory action of the diaphragm 26 is passed from its perimeter to the housing 15 the junction of the perimeter of the diaphragm and the housing forming a node as diagrammed in FIGS. 7 and 8. When operation is in the first mode, as illustrated in FIG. 7, the upper section 65 of the housing is flexed as indicated by the broken lines 70 and 71 inasmuch as opposite ends of the upper section are anchored, namely, respectively to the partition 25 of the lower end and to the closure 62 at the upper end. The lower section 66, however, vibrates in a different pattern in that only the upper end of the lower section is anchored, namely, to the partition 25 and lower end being unsupported. The lower section will, therefore, vibrate as indicated by the broken lines 72 and 73.

Vibrations generated as described take place and produce cavitation in the production fluid 14. The movement of the upper and lower sections of the casing have been greatly exaggerated in FIGS. 7 and 8 for purposes of illustration. In actual practice the movement is relatively small but adequate for setting up a corresponding cavitation effect in the production fluid 14. In point of fact, the sizes and masses of the diaphragm and other portions of the housing including upper and lower sections as well as the closure 62 are calculated so that for a selected embodiment of the apparatus when subjected to vibration at a frequency and amplitude provided by the motor 33 vibrate in a condition approaching resonance, namely, at one or more of their natural frequencies. This makes possible a very economical source of power while achieving substantially a maximum transfer of energy from the motor through the apparatus and the production fluid to the perforated liner 13 which needs to be cleaned. The liner surface is excited as a result of the vibratory energy being passed to it by the fluid and the liner together with dirt and incrustation particles on it, and the perforations in it are similarly excited and progressively loosened so that the material thereby dislodged falls free to the bottom of the well. The vibratory and cavitation cleaning action may be continued as long as necessary until the well has been cleaned. An appropriate closed circuit television may be employed to inspect the operation so that when the well is finally cleaned it will be observable by the operator, whereupon the cleaning action can be suspended and the apparatus withdrawn from the well.

To additionally facilitate the cleaning of the well, as well as making certain of the condition of the production fluid, a cleaning fluid may be dispensed, vibrated and excited simultaneously by the apparatus. Such a cleaning fluid may be either a chlorinating compound or other appropriate cleaning fluid, depending on the type of well being cleaned, the character of the production fluid, and other characteristics which may be met in any particular installation.

When cleaning fluid is to be dispensed, there is provided a capsule 75 which is mounted in the lower open chamber 28 as shown in FIGS. 2 and 3. An effective mounting is one making use of a spider 76 having legs 77, 78, and 79 the outer ends of which are fastened to plates 80 welded or otherwise secured to the inside surface of the lower section 66. A top plate 81 of the capsule 75 is anchored to the spider 76 by means of a bolt 82, which extends upwardly through the capsule from a bottom plate 83 through a sleeve 84. Resilient shear mount bearings 74 are connected between legs 77, 78, 79 and plates 80 to prevent vibration from being transmitted to the capsule 75 and also to prevent restriction of movement to the lower housing 66.

In the event that the capsule is to contain a dry treating material 85 a wall 86 of the capsule may be made of screen material so that as the dry material slowly dissolves, partly by reason of its nature and partly by reason of the fact that it is being cavitated, the cleaning material will pass progressively outwardly from the capsule into the production fluid of the well where it will be thoroughly mixed as a result of the cavitation action as the cleaning operation progresses. A cover 87 closes a feed port 88 by means of which the material 85 may be fed into the capsule prior to the beginning of the operation. Moreover, with a capsule constructed as shown, extra capsules may be kept in readiness and used as replacements for a spent capsule merely by unscrewing a nut 89 at the lower end of the bolt 82 whereupon one capsule may be removed and another one applied.

In the second embodiment of the invention illustrated particularly in FIGS. 10, 11, and 12 a power source 90 for sinusoidal vibration energy is mounted upon a base 91 and the base in turn fastened to a boss 92 forming part of the diaphragm 26 of the partition 25. Certain commercial industrial vibrators are available of such character that, when in operation, they are capable of vibrating sinusoidally any piece of apparatus to which they may be attached by means of the base 91.

In the embodiment of FIGS. 10 and 11 such a power source is one electrically operated and supplied by an electric cable 93.

A second type of capsule 95 is shown in the apparatus of FIGS. 10 and 12 and is of a character such that it can be substituted for the capsule 75 previously described.

The capsule 95 is adapted to provide a reservoir 96 for pressurized liquid acid material, the capsule having closed top and bottom plates 97 and 98 respectively, and a cylindrical imperforate side wall 99. For dispensing liquid from the capsule there is provided a dispensing ring 100 having small perforations 101 extending around the perimeter the ring being fed through a supply pipe 102 connected to an outlet port 103 in the bottom plate 98. Appropriate valves 104 and 105 are shown for regulating the flow. A fill port 106 is shown provided with a shut-off valve 107.

In this embodiment of the invention the housing 15 is set in vibration in the same manner as previously described by action of the power source passing to the diaphragm 26 and ultimately to the housing. Pressurized liquid acid material, for example, released by the ring 100 is driven to the well casing through holes 69 and cavitated at the well liner surface.

Claims

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A well cleaner for wells having a casing extending into the earth for collection of fluid prior to withdrawal, said cleaner comprising:

a housing,

a transverse partition dividing said housing into an upper chamber and the lower chamber, a mass in said upper chamber cyclically rotating on a substantially transverse axis, said mass when in a condition of rotation being a source of sinusoidal wave energy, and a source of power for said cyclically rotating mass, a bracket located substantially centrally on said partition and connected to said source of sinusoidal wave energy, said partition being of relatively stiff resilient material anchored at its perimeter to said housing whereby sinusoidal motion conveyed to the partition by said bracket is passed to the housing and vibration is set up thereby in said housing when at a location within said fluid whereby the fluid passes said vibration to the wall of said casing to loosen material lodged thereon.

2. A well cleaner as in claim 1, wherein there is a flexible power line extending from ground surface into the well to said well cleaner, said power line being adjustable up and down to raise and lower the position of said housing in the well.

3. A well cleaner as in claim 1, wherein a motor having a body rotating about a substantially transverse axis provides said mass, an end of said body in alignment with said axis having a vibration isolating mounting on said housing, a rotating shaft for said motor having an end opposite said one end of the body having an eccentric mounting on said bracket.

4. A well cleaner as in claim 1, wherein there is a tank for well treating material mounted in said lower chamber at a location clear of said housing, and material distributing means connected to said tank receptive of quantities of said material, and outlet means included in said material distributing means whereby said material is dispensed into the fluid in the well in response to action by said source of sinusoidal wave energy.

5. A well cleaner as in claim 1, wherein said upper chamber is air tight to provide buoyancy for said cleaner in the fluid.

6. A well cleaner as in claim 5, wherein the housing around said lower chamber is perforated to provide passage through said housing for said fluid.