US2259262A - Means for well cleaning - Google Patents

Description

Oct. 14,! 1941.Y 'K 'E M O'EHRL 2,259,262

MEANS FOR WELL CLEANING Filed NOV. l2, 1940 Patented oci. 14, 1941 2,259,262 MEANS Fon WELL CLEANING Kenneth E. Moehrl, Memphis, Tenn., assigner to Layne & Bowler, Incorporated, Memphis, Tenn., a corporation of Delaware Application NovemberV 12, 1940, Serial No. 365,235

(Cl. 16S- 20) 1 Claim.

This invention relates to improvements in means for. well cleaning, and has particular reference to apparatus for separating ,off a restricted length of well lscreen or strainer to localize a correspondingly restricted screen area for treatment, and subjecting such area to repeateds rge impulses alternately drawingl liquid in and forcing it out through said screen area, and particularly for supplementing and accelerating the cleaning action by chemical and heat treatment.

The instant invention is related to the invention disclosed in the application of Norris E. Gunderson for Means and methods for well cleaning, Serial No. 371,659, filed December 26, 1940, to which application reference is here made.

In certain types of Well a bore is dug from the surface of the ground into the Water or oil bearing sands and a strainer installed in the sand,

. this strainer in some cases being a metal strainer of extremely fine mesh and in other cases a screen f coarsef mesh surrounded by aggregate, the tw in the lattercase forming the strainer, this la ter type only being in the present instance illustrated. After the well is built it` is usually 'developed by pumping, such development being continued until clear water ows.

Also after wells have been in use for some time there is a tendency in some cases for the strainer structure to silt up and seriously impair flow, and in other situations a deposit of chemical, electrolytic, or other nature forms on the screen and/or the surrounding aggregate, it having been found in some instances that this deposit has substantially solidly lled a major part ofthe screen interstices and the well capacity has been reduced so much that the well is worthless.

In developing the'wells, or in cleaning the wells after they have silted up, a temporary pumping outfit should be used, but there is great reluctance to incur the expense of a temporary pumping out-y t, particularly since such outfit depreciates with great rapidity due to the Wear and tear of sand and silt bearing water, or such water mixed with chemicals which attack the pump structure. Often, therefore, the original or service pumps are used for the purpose, and the silt and sand or these materials mixed with acids damaging to the pump parts seriously impair the subsequent usefulness of the outfit.

rl'he present invention contemplates means for remedying such situations, improving well iiow, and restoring wells to usefulness; and particularly Ato means for such purpose which substantially eliminates moving parts subjected' to the action of such deleterious materials or actions.`

CII g The objects of the present invention are:

To provide means;

For segregating a screen area to localize treatment;

For establishing alternate suction and surge action on said lsegregated screen area;

For treating the segregated screen area with acid or other suitable chemical to eiect loosening or disintegration of adhering substances, and

,if desired, continuing such treatment into the 'surrounding aggregate or structure; and` For heating the treating chemical to accelerate the action, or heating alone should chemical treatment not appear indicated; and for combining the actions of heat, chemicals, suction, and surge.

A further object is to improve the detail of the device employed.

The means by which the foregoing and other objects are accomplished and the method of their accomplishment will readily be understood from the following specification upon reference to the accompanying drawing, which:

Fig. 1 is a sectional elevationishowing the upper or ground surface end of the device, and the lower or chamber end thereof, as installed for use, and a fragmentary portion of a well screen and surrounding aggregate and structure.

Fig. 2 is a substantially similar View showing a slightly modified form of the device.

Referring now to the drawing in which the various parts are indicated by numerals:

Il is the casing of a well bore extending downward from the ground surface I3. mentary portion of a screen, Il aggregate surrounding said screen, and I9 the liquid bearing sand which surrounds the aggregate. 2l is a string of pipe forming a column of sulicient length to extend from somewhat above the ground surface downward into the screen, the upper end Structure of this string preferably, as shown in Fig. 1, including a T 23, or as shown in Fig. 2, an elbow 23A, from either of which a lateral pipey 24 extends. Preferably also, this structure includes aT 25 and branches controlled by valves 2 6 and 21, leading therefrom, one

branch, as the branch controlled by valve 26,

leading to a lsource of chemicals, not shown, and the other serving as an overow.

The column 2l and head structure may be supported as bya cable 29 and suitable connecting means 3|, the cable 29 being raised and lowered by suitable hoisting means, not here shown, to correspondingly raise and lower the column 2| l5' is a frag- A4shift the lower end toward area of action.

between the column 2| and the chamber 39 formed between the screens. 4| is a pipe through which air. or steam is delivered to the head end .of the structure, this pipe, in Fig. 1, extending downward within the column 2| substantially to the v-head level, and in Fig. 2, as extending downv-which case the chemical valve is closed and the ward along the outside of the pipe and carrying y a nozzle structure extending into the pipe and upwardly turned, the column and fpipe, in either case, being constructed and adapted to function as the well known air lift type of pump when air is forced in through the pipe 4|. In either form the pipe 4| at its upper end,

, preferably hasbranches 43, 45, as for connection.

to sources not shown, of compressed air and steam respectively. 41, 49 and 5| are cut-olf valves.

'I'he pipe 4| may be slidably disposed through the T 23 to adjust the level of the lower end of the pipe 4| relatively to the column 2| if dei sired.

In making use of the device the assembly is lowered into the 'well until the heads 33 vand 34 are within the strainer section. Ordinarily they are lowered until they just enter the strainer section and work is subsequently done from the -top down, or they are lowered to the bottom of the strainer section and work done from the bottom up.

After the device has been thus lowered into the well and the spaced heads 33, 34 positioned to separate olf an. area of the strainer for `treatment. a suitable acid or other chemical is introduced through the valve 26 of the lateral pipe 24.,-the valve. 21 being closed. l This chemical passes downward through the column 2| and into the chamber 39 between the heads, and acts on the area of screenn or strainer surrounding the chamber. If desired, steam is introduced, as through the pipes 45 and 4|, the air control valve 41 and chemical and overflow control valves 23 and 2l being closed, heating the chemical. After the chemical has been allowed to act for a desired period of time compressed air is turned in through the pipes 43 and 4I and bubbles up within the column 2i acting in the usual manner of the air lift to raise the liquid in the column 2|, and at option discharge it through the overow valve 21, or back through the chemical valve 26 toward the source of chemleal supply. Tls action may be continued, in

,downward and be drawn upward, exerting outward and inward pulsations through the strainer. In such case ordinarily the overflow valve 21 is closed to conserve chemical, and the action is ordinarily repeated until the deposits on the area of screen under treatment are loosened and dislodged, after which the heads 33, 34, are lowered or raised, as the case may b e, to outline a new area of treatment and the foregoing operations repeated.

It will be understood that the successive introduction and cut-olf of air to produce alternate inward and outward surges of pressure through the screen may be used alone, or in connection with the acid treatment, or with treatment and heating, and, particularly in oil wells where choking up of the screen is often caused by parailln or other substances responsive to heat, that the chemical treatment may be dispensed with and heating alone resorted to.

Obviously during the introduction of steam.- the the overflow valve 2l opened and use of the air lift begun.

It will be understood that after the head structure of the device has been lowered substantially to ground level both the column 2| and the pipe 4| must be supported and additional sections of pipe added in order that further lowering may be accomplished; and that raising is accomplished in reverse manner Vby removing sections of the pipes from time to time as occasion may require.

I claim:

Means for cleaning an annular well screen and surrounding strata, including means longitudinallyspa'ced apartl in and cooperating with said screen for establishing' a chamber having a surrounding screen wall, a vertically disposed pipe column secured to said chamber-establishing means and extending upward therefrom above the earth surface, means for supporting and raising and lowering said column, a head structure on said column adapted for connection to a source of chemical supplyand for independent

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