US2674201A - Well swab - Google Patents

Description

April 1954 e. E. TALBOTT 2,674,201

WELL SWAB Filed Jan. 29, 1951 Fla! lnveni'or: Gus Ellsworth Tolbofl' HIs Ai'i'ornecj Patented Apr. 6, 1954 rumrso PATENT pence $521121...

'Gus EliTalbott Kilgore, TexJ aSSign'or to Sh'ell Development; Company, Emeryville, Calif.,'.a

I, corporationrof Delawai-e application'ranuary'zs, 1951, Serial N 0,208,271' 1 Claim. (01- 103 225) "'Ihis invention relates to an oil-well tool and pertains more particularly to an improved wellswab assembly for removing fluidand/ or parafiin, etd ffiiMthe-bore or a wellcasing or production tubing.

-Whe1i the reservoir pressure surrounding an oil well decreases to 'such an extent thatnatural fiowis not sustainedgthe well dies. A number of other-"things can cause the well to die such as production of water, reduction in gas-oilratio, a leak in-"surface connections which bleeds off solution-gas in -wel-l--bore etc'. Under favorable conditions,it isusually possible to induce flow and continue production-for some-time without the-necessit of pu'mpi ngr --This may be accom plished by the agitation of the fluid in the well bore by a*swabbing action. Generally, in carrying out the swabbing operation, a valved swab is dropped to thebottom of the well tubing on a wire linee -As the' swab is lowered'throughthe liquid in the well tubingits valve opens. allowing the liquidto pass upwardly therethrough. On: withdrawing the sw'ab from: the well; the valve automatically closes and all liquid above the-swab is lifted-thereby'upthe tubing andlout of the well. By :removingpart: ofwthe fluid column in the isreduced and more oil and gas will fiow arapidly into the bore from the surrounding well-wavity, thus: creating-upward momentum toicthe Lentire colummofi fluid. 1 Thesuction effects ':developed the swab also causes the gas in solution in. the oil: to berelease'd', thus reducing the. average density of the columniof fluidand furtherpermitting flow.-- Once-flow is started in this way it will often continue for some time without additional artificial assistance.

In-many oil fields, the oilproduced contains considerable quantities of paraflin which collects in-Jthe bore of the wellcasing or tubing to restrict the flow therethrough so that the well is not produced at the optimum rate.' In such cases; it' is often "possible to'resto'reproduction by aswabbing operation. A swab, carrying" one or more resilient cups or packing elements; is lowered-through said" well tubing 'and'subsequently withdrawn "therefrom during which operation the paraflin is: scraped from the inner wall of said tubing;

--Another"common I use of a well-swab isfor removing liquids, for example, drilling fluids from a wellboreupon completionofdrilling operations and before bringing a well into production. -In many cases, fluids cannot be readily circulated from the borehole, but insteadmay be removed from the well 'by a swabbing operation.

well bore the bottom hole pressure through its entire length, said bore Mhaving a '50 At times during aswabbing operation,- the swab maybecome'stuck or lodged in the well tubing;

resulting in the loss =of considerable operating time before it is eventually freed. It is therefore anobject ofthe presentinvention to provide a swabbing'apparatus: which may readily be freed when it becomes lodged in a well tubing.

It is also an object of this invention to provide a swabbing apparatus which may be referred to as valveless, in the-sense that it does not comprise any valve structure specifically designed as such and operating solely-for that-purpose,

the functions of a valve beingperiormed in the present apparatus by the-cooperationof structural elements having other primary'f-unctions.

It is also an object of 'thisinvention'to provide a device for swabbing wells which :does not employ any delicate valve mechanism which-may be easily stuck open or closed by an accumulation of paraflinor by a hard foreign object thatbecomes lodged therein.

Another objectof'the present invention is to provide a swabbing apparatus incorporating -a jarring mechanism adapted to. be lowered into a Lwell tubing on a wire line, whereby theaflow of 'fluid through the swabbing apparatus may be.

controlled. and said jarring mechanism may be actuated by: vertical movement 'oftsaid wireline.

A further object of this invention is to provide a .swabbing apparatus incorporating a jarring mechanism adapted to be actuated simultaneous 1y withthe opening and/or to fluidflow.

Theserand other objects of thisinvention'will,

lwieferrin'g to Figure 1 of the drawing, the

present swabbing apparatus comprises an elongated bar-member or body mandrel I l' having-an enlarged lower end l2 of greater'diameterthan' the rest of the bar-member; Slidinglymounted.

on said bar member I II is an elongatedtubular barrel, mandrel or sleeve l3 having a bore l4 diameter slightly greater than the diameter of the bar member I l whereby an annularrfl-uidpassageway I5 is formed-betweenthe barmember H and the '.barrel.l3.

Carried onthe outer surface of-the...tub ular barrel 13 in a fixed manner are one or more closing of the: device partly in elevation" swab rubbers or packing elements is and Mia having an outside diameter equal to or slightly greater than the well casing (not shown) in which the swabbing apparatus is to be used. The swab rubbers may be of any desired size and design and may be formed as, or consist of a plurality of swab cups 11, as shown. The swab rubbers l6 are normally made of a resilient material such as rubber, synthetic rubber, etc., and are fitted or formed on the tubular barrel 13 which imparts rigidity to the entire swab structure.

The lower end l8 of the tubular barrel may be enlarged, as shown, to form a shoulder 19 against which one end of the swab rubbers l6 may rest. A short tubular collar 20 may be threadedly secured to the upper end of the tubular barrel H to act as means for retaining the swab rubbers It in position on the barrel l3. The collar 26 is also provided with a longitudinal bore therethrough of a diameter slightly greater than the bar member H whereby an annular fluid passageway 2| is formed between said bar member H and the inner surface 22 of said collar 28.

In addition to the axial fluid passageway 2|, the collar 23 is also provided with one or more horizontal or radial fluid outlet ports 23 through the wall thereof. The bar member H is preferably cylindrical in shape but may have a cross section that is square, hexagonal, octagonal, etc. The length of said bar member l is substantially greater than the length of the tubular barrel l3 and the swab rubbers it carried thereon. Preferably, the bar member H is at least twice as long as the swab rubbers l6 whereby there may be substantial movement of the rubbers it along the bar member II.

The upper end it of the bar member H is threaded to engage a coupling or tool joint 25, preferably a tool joint having considerable weight. The lower face 26 of the tool joint 25 forms a shoulder on the bar member ll which is preferably of an area substantially equal to the upper face 21 of the collar 26. Other pieces of related equipment such as a wire-.ine coupling or a weight bar 28 may be secured to the upper threaded end 29 of the tool joint 25 in order to facilitate the lowering of the present swabbing apparatus into a well tubing.

As shown in Figure l, the shoulder in formed at the top of the enlarged lower end 12 of the bar member may be beveled. In this case, the cooperating lower edge 3| of the tubular mandrel is also beveled so as to flt in substantially fluidtight engagement against the shoulder Bil.

In the embodiment shown in Figure 2, the tubular barrel iii of Figure 1 consists of a plurality of tubular elements 3?. and 33 having fixedly mounted on the outer surfaces thereof individual swab rubbers 34 and 35. A tubular collar 36 having radial fluid outlet ports 31 therein may be slidably mounted above the uppermost swab rubber 34 without being fixedly secured thereto. If desired, radial fluid ports 38 may be formed in the lower face 39 of the tool joint 40 instead of ports 31 in collar 35 for a purpose which will be described hereinafter.

When individual swab elements 32-3l and 33--35 are slidably mounted on the bar member H together with collar 36, the upper and lower edges of said swab elements and the lower face of the collar 36 are preferably beveled as at Al, 42 and 43 in a manner similar to the beveled shoulder 30 whereby all the aforementioned elements temporarily register and interlock with each other in substantially fiuidtight engagement.

In carrying out a well-swabbing operation, the present swabbing apparatus is secured to the lower end of a weight bar 28 which in turn is suspended from the lower end of a wire line or cable (not shown) and lowered into the well casing (not shown) to be .swabbed. In running the swabbing apparatus into the well, the outer edges of the swab cups ll may frictionally engage the walls of the well casing causing the swab cups H and tubular barrel 13 to be moved upwardly on the bar member ll so that the upper face 2? of the collar 20 engages the lower face 26 of the tool joint 25. As the swabbing apparatus is lowered in this position, any fluid in the well casing passes upwardly through the annular passageway l5 and out the fluid ports 23 in the collar 20.

When the swabbing apparatus is being withdrawn from the well, an upward force pulling on the cable (not shown) causes the bar member H to move upwardly with the swab rubbers l6 remaining stationary until the beveled shoulder 38 on the lower end of the bar member ll engages the beveled seat 3| on the lower end of the tubular barrel [3 to close the lower end of the amiular passageway l5 and prevent the escape of fluid downwardly therethrough. As the apparatus is pulled upwardly, the swab rubbers l6 frictionmly engage the wall of the casing preventing any fluid from escaping. Thus, any fluid, mud, deoris, or paraflin accumulation above the swab rubbers H5, is moved upwardly ahead of the swabbing apparatus to the surface of the well.

In the event that the swabbing apparatus becomes lodged in the well tubing as it is being drawn out of the well or as it is being run into the well, hoisting or lowering is stopped and tension on the cable is'removed momentarily to allow the weight bar 28 and bar member ll attached thereto to drop suddenly, causing the lower face 28 of the tool joint 25 to strike the upper face 21 of the collar 28 sharply. If this operation does not dislodge the swab cups in the well casing the operation may be repeated several times until the jarring action releases the apparatus.

While a small amount of fluid is normally lost through the apparatus during the jarring action, in some cases it may be found desirable to release the tension on the hoisting cable until all the fluid above the swab rubbers l6 has drained through fluid ports 23 and passageway [5 to the bottom of the well. With the weight of fluid removed from above the swabbing apparatus,

the jarring action may be repeated, if necessary, in the manner previously described and the apparatus may then be withdrawn from the well or run into the well again. The swabbing operation may be repeated as many times as necessary in order to remove all the fluid or other material from the well.

It is to be noted that the present swabbing apparatus is provided with fluid passage means which is open when the apparatus is being run into a well, thus allowing its rapid descent to the bottom of the well. On removal of the apparatus from the well, this fluid passage means is automatically closed. At the same time, if the apparatus becomes lodged in the well, it may be readily jarred loose by manipulation of the wire line to which it is connected.

I claim as my invention:

An apparatus adapted to be lowered on a wire line into a well for operation as a combination Well swab and as a jar, said apparatus comprising an elongated bar member, radially extending stop shoulders formed at either end of said bar member, at least one tubular sleeve co-axially mounted for limited sliding action along said bar member between said stop shoulders, said bar member being at least twice as long as said tubular sleeve, the inside diameter of said tubular sleeve being greater than that of the bar member whereby an annular fi'uid passageway is formed between the inner wall of the sleeve and said bar member, resilient swab cup means oarried outwardly on said tubular sleeve, said swab one means being of a diameter to engage frictionally the inner wall of a well casing when the well-swabbing apparatus is moved therethrough, a collar mounted on said bar member above said sleeve and slidable with said sleeve, the upper face of said collar being substantially equal in area to that of the lower face of the upper stop shoulder, and weight bar means fixedly secured at all times to the top of the elongated bar member eo-axially therewith whereby a sharp jarring action may be repeatedly applied to said tubular sleeve and swab cup means by reciprocation and impact of said weight bar means and said bar member against the top of said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS

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