Explosive screen cleaner

Nov. 14, 1944,

Μ. M. KINLEY

EXPLOSIVE SCREEN CLEANER

2,362,829

Filed Aug. 18, 1941

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Patented Nov. 14, 1944

2,362,829

UNITED STATES PATENT OFFICE

2,362,829

EXPLOSIVE SCREEN CLEANER

Myron M. Kinley, Houston, Tex.

Application August 18, 1941, Serial No. 407,340

Claims. (Cl. 102—21.8)

This invention relates to screen cleaners and more particularly to screen cleaners of the explosive type and particularly adapted to remove clogging material or debris from the openings in a screen in deep wells.

The primary object of the invention is to provide an explosive cleaner that will open the passages in a clogged screen while it is in the well bore.

Another object is to provide a cleaner that will effect the desired cleaning operation without damage to the screen liner.

A further object is to provide a cleaner which will effectively clean either slotted or perforated screens.

Still another object is to provide an explosive screen cleaner made up of frangible material so that such material is reduced to a form that will not hamper the operations of producing the wells after the screen has been cleaned.

Still another object is to provide a cleaner which includes means for maintaining the cleaner assembly centrally of the screen to be cleaned at the time of detonation of the explosive carried by the cleaner.

Another object is to provide a novel method of cleaning well screens through the use of an explosive which is so positioned as to give rise to an explosive impact which emanates from a plurality of spaced centers.

A more specific object is to provide a screen cleaning assembly which includes a central tubular member containing an igniting explosive to discharge the main body of explosive which is carried within spaced frangible cups mounted upon such member.

The foregoing objects are primary objects and will, together with additional objects, be more fully apparent from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a sectional view through a well screen and the upper portion of a cleaner assembly embodying the invention;

Fig. 2 is an elongated view showing an assembly within a screen and also illustrating one construction and manner of discharging the explosive.

The well cleaning device as illustrated in the drawing is lowered upon a cable I which may be a conductor cable so that electrical means may be utilized to set off the explosive. Such cable may be an ordinary wire cable attached to the lowering head 2 which is provided with a firing pin 3 having a head 4 for engagement by a mem10 ber such as a go-devil 5 (Fig. 2) which is dropped over the cable I from the mouth of the well bore after the assembly, hereinafter described, has been lowered to the desired position within the screen 6. Alternately it is apparent that the explosive used with the device may be discharged by means of an ordinary time bomb.

In the embodiment as shown, the lowering head is of relatively sturdy construction and it is intended that such head may be repeatedly usable with explosive assemblies such as that hereafter described. This construction of the lowering head 2 assists in the rapid lowering of the assembly to the desired position within the well.

The lowering head is threaded internally at 7 to receive the upper end of a small tube 8 of frangible material such as a frangible synthetic, aluminum and the like. A cap member 10 such as an ordinary type of blasting cap containing fulminate of mercury or like material is placed on the upper end of the tube 8 and is engageable by the firing pin 3 to initiate combustion of an explosive such as the rod or string of cordite which is a stick of explosive to some extent, similar to a fuse ti which, together with a plurality of blasting caps 12, fills the interior of the tube. While an alternate arrangement of the explosive cordite and the blasting caps has been shown these elements are merely for the purpose of conducting the fire from charge to charge of explosive. The cordite is found to cause detonation of the explosive 14 somewhat better under the existing conditions than does the blasting caps so that a section of cordite is disposed in each charge of explosive.

At spaced intervals along the tube 8 are provided a plurality of annular cups 15 of a frangible material such as a frangible synthetic or aluminum. These cups are of materially smaller diameter than the screen 6 but are of a size to contain a proper amount of explosive 14 such as dynamite that the detonation thereof is effective in producing a desirable explosive force to clean openings IT adjacent thereto. The cups f5 are so spaced longitudinally of the tube 8 that their combined effect is such as to effectually clean all of the openings 17 throughout the length of screen within which the assembly is located. The fire initiated by the firing pin 3 will travel along the cordite and blasting caps ί 2 as a fuse to set off the cups of explosive IS in sequence.

To facilitate uniformity in results the invention also contemplates the provision of a plu-

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2,362,829 rality of sets of spring fingers 20 which are attached to the tube 8 by means of collars 21. It seems apparent that through the use of two or more, of these sets of fingers the explosive assembly is maintained concentric with the screen 6 and hence the explosive force produced thereby acts uniformly in all directions.

The operation of the device of the invention is believed apparent from the foregoing description. By way of summary it may be stated that : the assembly including the tube 8, cups 15 and the fingers 20 are attached to the lowering head 2 and lowered by means of the cable I to the desired position within the screen 6. The desired explosion is, then initiated as by means of the : go-devil 5 engaging the head 4 of the firing pin 3. The resulting explosion of the cordite ί I, the blasting caps 12 and the explosive charges 14 . within the cups 15 is substantially instantaneous, and sets up a high pressure area in the screen ; adjacent the cleaner assembly which creates a blast against any material clogging the perforations, slots, or screen openings and tends to dislodge such material and to thus clean the screen, the cleaning effect produced thereby ex- ; tending throughout the entire length of the cleaner assembly.

If an additional length of screen is to be cleaned, the lowering head 2 may be withdrawn and a second assembly attached thereto and ; lowered to such additional section of screen to be cleaned thereby. It is, of course, obvious that the cleaner assembly may be of any desired length so that a single assembly may be utilized for cleaning the length of screen for which the assembly is designed. While the explosive charges have been shown and described as individual spaced charges, a continuous charge approximating the length of the area to be cleaned may be used.

Attention is directed to the fact that the use of frangible material for the tube 8 and the cups 15 is instrumental in providing a minimum of debris from the assembly. This debris may, if desired, be removed from within the well but it has been found that such debris offers no difficulty if allowed to remain at the lower end of the well bore.