US2363644A - Oil well casing pump - Google Patents

Description

Nov. 28, 1944.

H. D. COLLINS OIL WELL CASING PUMPh Filed Dec. 4, 1942 INVENTOR, H055?? D. 60u /N5 o Patented Nov.`28, 1944 o aseam ,omWELL misma `PUMP L Hubert podiums, rinse, ok1a.`,`assign0r ,to Lam` "tex 'Equipment C'orporation,Fo`rt Worth, Tex.,`

ajcorporation of Texas.

I Appuatim `December 4, 1942. serial No: 4stats u u, UNITED STATES eATENT o FFICE N;

10 claims. `(o1.10sneen This invention relates to `new "and useful -improvements in pumping mechanismslfor flowing oil wellsand thelike. l It' deals particularly with o wellpumps of the type known as casing pumps,

Also, the resilient packer is likely to `drag against .rromawell after pumping operations. v i

or pump head, it is first necessary `to li'ft the mandrel out :of the packer-so that the seal between the top of thepacker and the well `casing may be broken. The .column of 'oil `lying -above thefpump, however, still bears on the packer and hinders movement of thepump assembly. `For relief from this condition, drainage ports have heretofore been provided lin a drain sleeve* just below the packer, so that oil :may Pass; between the packer and a `draintube fthatudepends the mandrel,` andthentfhroughrthese drainage ports. Also, circular rows fof drainage holes have tion which reduces the likelihood lof damagefto the packer` during movements of the pump inra o Well casing,`

`Another object ofthis invention is to provide a casing pumpnconstruction whichfenables free drainage of liquid past the packer when the mandrel is unseated, and `which prevents solid matter i `from entering and lodging in the space between the drain tube and the packer,

`Another object is to provide a `easingvpump construction `which eliminates `the usual `radial drainage holes in theidrain sleeve below the packo er yet overcomes the `cliiieulties which itis the purpose of vsuch structure to avoid. l

A `further object of this invention is to provide y a casing `pump construction which is smaller beengprovided inthelower endof the ldraintube i andnin the drain4 sleeve, :respectiwelmso as `:to i

register and allow drainage `when the mandrel is lifted .from the packer iandto `.be-sealed ioff :from

each other by an intermediatepacking whenthe mandrelis seated in the packer. i

:Notwithstanding theY provision `Lof :such strnctures, trouble frequently `is yencountered in ne moving the `.us-ual casing pump `'from a 4wellv hole. t

the :casing and be damaged :both whenremoving the pump .and when running iitinto :the hole.1 A

metal 4packer shoe sometimes is attached to the lower side Aof the packerto `protest `it against darnage duri-ng the ,lowering of thewpump .inte the well.` 1A :furtherusource of` :trouble `is #that the drainage ports Jjust below thelpaekerrsometimes becomevclogged by` shale, `sand .or other'solidmat terpassing and Alodging between the packer and the drain tubewhen the mandrel isunseated. Moreover, the usual casing pumpfiseomparatively large and requires extra materialien-ndmachine Work for :its manufacture, as compared 'with 4casi l `Another object is to providepsuch.aieonstruc- ,u N uso` One `ofthe objects :of this inventionisitofproin lengthand 'lesslcostly -to manufacture than known oil well casing pu-mps. y

The `foregoing and other features and advantages of my invention will become apparent from the vfollowing description of an illustrative embodiment thereof, when considered in connection i with the accompanying drawing, in which, Figure 1 andFigure la are longitudinal views,`

partly in cross section, showing, respectively, up* per and lower portions of the illustrative pump i mechanism; i i

Figure 2 isa fragmentary elevation of part of` the drain sleeve and `drain tube assembly;

'Figure 3` is a 'transverse cross section substantially along line 3 3 of Figure 1; and

Figure Il is an enlarged longitudinal cross section showing fthe mechanism of "Figure l with o parts of Figure 1` disposed in pumping condition,

with the ,mandrel `I2` `seatedinand `sealing the packer` I4 against the surrounding casing. t A

pumprod Iii` forms partei the usual string of sucker `rods (not shown) b y which to loweror raise the pump in the Welland to reciprocate the pump piston `or suckerl (Fgurela) when the pump is located andsealed in pumping position.

The piston I8 operates a working barrel 20 and carries a travelling valve 22 and sealing rings `or .gaskets 2.4. A valvefhousing .26, secured to the lower end` of the working barrel, .encloses .a standing valve 28 throughwhichoil is `,admitted `from `the well formation into the Working barrel on the upward stroke ofi piston i8. Thexpump assembly may be supported atpumping position '56 in any known manner, such as `by a suitable an@` choring device (not shown) attached thereto below the working barrel.

The working barrel 20 is connected with the packer I4 through tubular means including a drain sleeve 3U and one or more coupling sleeves or adaptors 32. The packer itself is made of an oil-resistant synthetic rubber, such as Neprene, or of other suitable rubber-like material, and is constructed in a novel manner as hereinafter described. The `packer is permanently molded and bonded to a bushing I5, by which it is firmly secured to the upper end 3| of the drain sleeve 30.

A drain tube 40 fits inside of the drain sleeve 3D and is movable axially with respect thereto to a limited extent determined by the length of an axial slot 42 in the drain sleeve and thesize of a lug 44 that is fixed to the drain tube for sliding movement in slot'42. The slot has a horizontal leg 43 at its top to receive the lug and thus hold the drain tube assembly a-gainst substantial axial movement during the raising or lowering of .the pump in a well. The drain tube 4D depends from a pump head 50, to which it is directly'attached. Pump rod IG extends vertically through the drain tube 40 and pump head lill. The lower part of frusto-conical in shape so as to fit into and expand the packer I4. The head 5@ is hollow and has lateral openings 52 therein so that oil may pass upwardly from theworking barrel through the drain tube and pump head and thence into the casing I Il above the packer.

According to the present invention, the expansible packer I4 is formed and constructed to have a minimum diameter adjacent its top portion, so that its inherent resiliency will strip it away from the casing. Ill when the mandrel I2 is unseated, and preferably also so that it ts closely against the drain tube 4t in its normal unexpanded condition. As illustrated in Figure l, the outer surface of the packer is made to curve or taper inwardly from its middle portion I4a t0 the top portion I4b, so that the pack-olf or sealing effected by forcing the mandrel thereinto occurs adjacent the middle portion of the packer, substantially as shown in Figure 4, instead of at the top only as in prior casing pump constructions. Also, the innersurface of the packer preferably is made to curve or taper inwardly to a slight extent from the bottom almost to the top portion thereof, which further ensures self-induced inward movement of the packer into sealing engagement with the drain' tube 2li when the mandrel is unseated. i In other words, the average diameter of the packer preferably decreases progressively from the bottom substantially to the top portion thereof. At the top of the packer, as shown at I4c, the inner surface preferably curves outwardly to facilitate seating of themandrel and cause the pack-off zone to extend to the middle portion I4a.

With the packer so constructed, the packer strips itself away from the well casing Ill and provides the maximum available space between its outer side and the casing whenever the mandrel is unseated, so that the drainage of liquid past the packer is materially improved. The same construction alleviates the danger of damaging the packer during the lowering or the raising oi the pump in a well, thus making it unnecessary to attach special: metal packer shoes under certain conditions. Also, the drainage ports usually provided in the drain sleeve just below the packer may be eliminated, leaving the drain sleeve imperforate atV that location; and since the packer moves into sealing engagement with the drain tube 40 as the mandrel is unseated,

liquid and suspended solid matter are prevented from entering and lodging in the space between the body of the packer and the drain tube (see Figure l). A further featurepf this construction is that the packer may be made shorter than heretofore without lessening its sealing effect or its resistance to hydrostatic pressures.

yTo'permit drainage of oil through the pump head and drain tube when removing the pump from a well, radial drainage ports 4I are provided near the lower end of the drain tube 40, and the slot 42 which receives lug 44 is cut entirely through the drain sleeve and connected with an inwardly facing annular groove 45 in the drain sleeve so that the drainage ports 4I will communicate with and drain through the groove 45 and the pump head constitutes the mandrel I2, being pump, adapted to be packed by a tapered man- 'n slot 42. when the mandrel is lifted, as shown in Figures 1 and 3. A suitable packing ring 54, such as 'a chevron packing, is disposed between the lower endof the drain sleeve 3l) and the drain tube 4U to permit relative sliding movement of the drain tube yet form a leak-proof seal when the parts are in ypumping condition', as in Figure 4. vvThis single packing ring suffices. The arrangement of the slots'42 for registration with as intended to be set forth in the appended claims.

I claim: l 1. An expansible packer for an oil well casing drel into sealing contact with a surrounding well casing, comprising an annular body of elastic material having its outer surface tapering inwardly from its middle portion to its top so as to be'packed by the mandrel adjacent its 'middle portion and to strip itself away from the casing l tending into the `sleeve and slidable relativev thereto, a mandrel at the top of the drain tube and an annular expansible packer secured to the top of the drain sleeve to be packed by the mandrel into sealing contact with a surrounding well casing, a packer' having its outer surface tapering inwardly from its middle portion to its top portion and .having its inner surface tapering 4. An expansible packer for an o'il Well casing pump, adapted to be packed by a mandrel into sealing contact with a surrounding wellcasing, comprising an annular rubber-like bodyy the outer surface of which is substantially vertical from its bottom to its middle portion and tapers the pump from a well casing, aninner drain tube extending into the sleeve andV slidable relative thereto, a mandrel at the top of the drain tube andan annular expansible packer of rubber-like composition secured to the top of the drain sleeve, a packer formed to be packed by the mandrel `adjacent its middle portion to seal the pump in l a well casing and having its minimum diameter adjacent its top portion wherebyto strip itself from the well casing and form a seal with the drain tube when the mandrel is withdrawn therefrom.

6. In an oil Well casing pump comprising a` pump barrel, a drain sleeve connected with the top of the-pump barrel to facilitate removal of the pump from a well casing, a draintube eX- tending into the sleeve `and `slidable relative thereto, a mandrel at the top of the drain tube and an annular expansible packer secured to the top of the drain sleeve,. a drain sleeve which is imperforate adjacent the packer and a packer formed with means for stripping itself away from a well casing and for `holding itself-in sealing contact with the drain tube when the mandrel is withdrawn from the packer.

7. In an oil well casing pump comprising a pump barrel, a drain sleeve connected with the top of the pump barrel to facilitate removal of the pump from awell casing, a drain tube eX- tending into the sleeve and slidable with respect thereto, a mandrel at the top o-f the drain tube and an annular expansible packer secured to the top of the drain sleeve to be packed by the mandrel into sealing contact with a surrounding well casing, intertting lug and slot means respectively on the drain tube and inthe drain sleeve to` limit relative axial movement thereof, a slide packing in side the drain sleeve below said slot means to seal the drain sleeve to the drain tube when the mandrel is seated lin the packer, said slot means opening through the wall of said drain sleeve, and drainage means opening through said drain tube nearthe lower endthereof and l is seated in the packer, said drain sleeve being disposed toregister with said slot means when the mandrel is withdrawn from the packer l above the pump in a` whereby to drain oil from well casing.

8. In an oil well `casing pump comprising a pump barrel, a drain sleeve connected with the top of the pump barrel to facilitate removal of the pump from `a well casing, a drain tube eX-V tending into the sleeve and slidable with respect thereto, a mandrel atthe top ofthe drain tube and an annular expansible packer secured tothe top of the drain sleeve to be packed by the mandrel into sealing contact with a surrounding well casing, interfltting lug and slot means onthe drain tubeand in the drain sleeve, respectively, to limit relative axial movement thereof, said slot means opening through the wall of the drain sleeve, drainage means opening through the drain tube and disposed to communicate with said slot means when the mandrel is withdrawn from the packer, packing means between the drain `sleeve and drain tube for sealing off said drainage rneansfrom said slot means when the mandrel imperforate above said slot means and said packer being formed to `strip itself away from the well casing and fit closely against the drain tube when the mandrel is withdrawn from the packer whereupon `to provide free passage of liquid between the packer and the well casing and simultaneous flow of liquid from the drain tube through said drainage means and said slot means.

9. A packer unit for an oil` well casing pump or the like comprising l av cylindrical bushing threaded for connection to the upper end of a tubular pump element and an annular` expansi- -blepacker of rubber-like material molded and bonded to said bushing, said packer having its average diameter` progressively decreasing from` the bottom substantially to the top portion thereof.

iQ. In a casing pump for oil wells or the like comprising a cylindrical drain sleeve adapted to be connected with a pump barrel and to carry '.an expansible packer at its upper end, a cylin.-

drical bushing threadedly connected to the upper .end of the drain sleeve and an annular expansible packer of rubber-like material molded and bonded to said bushing, said packer having its average diameter progressively decreasing from the bottom substantially to the top portion thereof, said drain sleeve having an inverted -L-shaped slot cut through its wall and being otherwise substantially imperforate.

HUBERT D. COLLINS.

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