US2669940A - Sucker rod sand trap - Google Patents

Description

Feb. 23, 1954 w. s. CRAKE SUCKER ROD SAND TRAP 2 Sheets-Sheet l Filed May 24, 1952 len Feb. 23, 1954 W, $CRAKE 2,669,940

SUCKER-ROD SAND TRAP Filed May 24, 1952 2 Sheets-Sheet 2 lnveni'or.;

wsmKe Patented Feb. 23, 1954 [TED SUQKER ROD SAND TRAP WilfredrSiCrake, Kilgore, Texi, assignor;l tov Shellv Development Company, Emerrvilla Calif. a1

eorporationoi Delaware Thisinvention relates-to'well production equip--V ment andipertains more particularly to appara'- tus adapted to prevent or minimize thesettling. of" sand within a well vvhiclrisl being produced by reciprocatingasucker rod-pump.

Insome oilI fields varying quantities offsandl are-pumped to the surfacealong with theoiL Frequently, a` well prime mover'which recipro Cates the pumpmay stopdue to breakdown of somepart ofy the'equipment. linl other instances the Well prime mover may be automatically or manually ystopped periodically on a set time schedule-When the Well/is being producedby intermittent pumping. Forexample, in WellsW-herethe capacity of thel pump-isigreater thanthe amount ofioil owing-from the oilfbearingiormation into theiwell borehole, thewellpumping installation may be shut ofi: for. predetermined periods, say 12 -hours out-ofevery day;

When the Well pumping installation-is stopped, the sand carried in suspension by thecolumn of oilin the production .stringA settles tothe bottom ofl the-Well4 andpilesfupon. the top of` they pumpplunger.y and. clogs the valves; This causes sand` ing(r up ofi theA pump-which often requires` thed removalof. the'pump plunger. forrepairs..

It isqthe'primary object ofthe present; invention to.providarelatively simple and inexpensive Sandi-trapping apparatus-.adaptedto bevpositioned.y in. an. oil. production, tubing string, above.: a. re.\v ciprocatnge. wellA pump, for preventing sand from. settlingv` on the.: pump when? the y pump.- is not, op?. erating.

Another.y Object of. this invent-ion; is ,i to; provide sand catching. apparatus ,Whichfmay bey easily. in.

stalled along4 al string; of; sucker. rods'. above. a,

plunger-type pump.- withinl a wellL borehole for. catching Sand. at diiierent levels as; itl settles out', of the column or oil above thepump whenthe, pumpisnot operating.

A; further object of this invention istor provide simple and effective sand-trappingappara:-v tusadaptedto be. secured to a suckerfrodstring thegproductionvtubing, above a reciprocating: WellE pump for ei-eetivelyy closing. the production: tubing atvarying levels when the` pump is not` operating, saidapparatus at the same time .beingl adapted toppen the tubing andrallow oiltoibev produced: therethrough when thepump isoper.- ating.'

Another object of' thee present invention isto provide sandftrapping devicev adapted tobe mountedz onx a. sucker rod;A string; within a Wellv production; tubing to form. a., substantially.; horie.. Zmtalzbarrier. within, the production; tubingiupon.

2 Wnicli-sandfmaysettle-When the Welll'is not pumping, there being a seal formed betweenthe'san'dh. trappingrbarrier andthe production tubing, Whichseal= becomes morepositive as greater quantities off sand settle thereon;

These and other objects of this inventionwill-v be understood from the following description taken with reference to thedrawings, wherein:

Figuresrl and 6 are longitudinal views', partly incross-section, or the present sand-trappingr apparatus-mounted ona sucker rod string above` a reciprocating well pump in a stringof produc-i;

tion-tubinga Figures 2, 3 and 4- arediagrammatic vieWsoff the present ,sand-trapping apparatus during vari-M ous phases of Wellprocluction operations.

Figure 5-is a View, partly in cross` section, of` the. present sand-trapping apparatus having asemi-rigid type construction.

Referring to-Figure l of the drawing, al pro-H cluotion orpump tubing H is shown vertically positionedinaV manner similar to its position in the well casing or borehole of an oill Wellwhiehy is produced by a Well pump of the reciprocating type.

The top of the pump plunger unit` l2, which1 forms the valve cage for a traveling ball valvetrapping barriers li which are made ofr a flex-- ible material such as rubber, synthetic rubber,V rubberizedk canvas or various plastic materials.. Preferably, an oil-resistant .material is .employedf thus` reducing 'the rate at which the barriers deteriorate andbecome Worn out.

Eachr sand-trapping barrier i5 is a substanf-f tially flat flexible disc, preferably having acont-A.

c-ave upper: face l5 or formed in a. concave; section, as illustratedin Figure 1.

Secured to or, integrally formed on the' bottom.

of the-disc iii is a short cylindrical section. lil: which is: preferably made of the same flexible.' mater-ialasthe disc l5. Anaxai hole I8.1 is. pro-@1. vided in the` disc it' and cylindrical. section. H through which a sucker rod i4. extends. diameter'ofr the hole i3 in the disc l5 isslightly,

smaller. than4 the diameter of: theA sucker rod soi that the ythrpat vofrthe l disc l5; formedaby.. theoyet lindrical section il clamps on the suclrenfrud |42A The"r 3 in elastic tension to hold the disc I5 fxedly positioned on said rod I4. The cylindrical throat section I'I has suicient gripping power to hold the disc I5 in place during the reciprocation of the sucker rod string.

The sand-trapping disc I5 is of a diameter substantially equal to or slightly larger than the inside diameter of the production tubing I I. The disc thickness is determined by the strength of the disc material and the diameter of the tubing string II, the thickness being sufficient to support a substantial quantity of sand which settles on the disc I5 in its stationary position. One advantage of employing a disc I5 having a concave upper surface, as shown, is that increasing amounts of sand settling on the top of the disc I5 weigh and depress the outer edge of the disc slightly down so that it is pressed tightly against the inner Wall of the tubing string II thus preventing any sand from falling past.

In some pumping installations a sand-trapping disc 20, shown in dotted outline, may be employed having a flat or horizontal upper surface. Discs 20 of this structure are preferably of a diameter which is slightly greater than the inner diameter of the tubing string II.

Installation of a sucker rod string of a sandtrapping barrier comprising disc I5 and throat section I'I is accomplished by stretching the disc radially whereby the hole I8 therethrough is enlarged so that the barrier may be forced over the coupling and upset 2I of the sucker rod I4.

It is realized that the present sand-trapping barriers may be constructed oi a separate flexible disc 22 (Figure 5) xedly secured to a rigid collar 23 which is either permanently or removably secured to a sucker rod I4 as by welding or bolting. The disc 22 is secured to the topof the collar 23 by any suitable means, as by a holding ring 24 and bolts 25. The rigid collar 23 may be of split ring construction fastened together by bolts 26 to facilitate its installation on the sucker rod string.

Preferably, the sucker rod string I4 is equipped with a plurality of centering guides which comprise a cylindrical body member 28 having three or more radially extending guide plates 29 integrally formed thereon or afiixed thereto, as by welding. The upper and lower ends, 30 and 3l respectively of the body member 28 may be threaded for connection between the ends 2| and 32 of two sucker rods. The sand-trapping discs I5 are preferably secured to the sucker rod string I4 near the centering guides 28-29 so as to minimize the Wear due to frictional contact between the discs I5 and the inner wall of the production tubing string I I. The plates 29 of the centering guide extend radially over a distance slightly less than the inside diameter of the production string I I so that the centering guide may freely move axially within the tubing string while maintaining the sucker rod string I4 substantially in the center of the tubing.

The discs I5 are also preferably secured to the sucker rod string I4 just above a tool joint I9 or 32 or just above a centering guide which is threadedly connected into the sucker rod string. Thus, sand accumulates on the disc and piles up around the smooth portion of the rod, or that portion having the smallest diameter, rather than around a tool joint, thereby reducing the hazard of sticking. If desired, a sand-trapping disc 40 may be attached directly to body member 23 of the centering guide rather than to the sucker rod string I4,

v35 on top of the disc.

In operation, when the pumping installation is shut down the sucker rod string I4 is not reciprocating, the sand-trapping disc remains stationary, as shown in Figure 1, and any sand being carried by the production iiuid settles in a pile The same action takes place at each disc which is secured to the sucker rod string with the sand carried by the Well iiuid between any two discs settling out on the lower disc.

When the pump is started again the agitation of the oil in the tubing string due to reciprocation of the sucker rod string I4 and the attached discs I5 causes the sand which has accumulated on the discs to be swept off and again suspended in the stream of well iiuid as it is pumped upward and out of the well. Since the well fluid both above and below each disc I5 moves upward during the upstroke of the pump, the disc I5 maintains its normal unflexed position, as shown in Figure 2, with the outer edge of the disc touching or in substantial contact with the inner wall of the tubing string I I.

On the downstroke of the pump the outer edge of each disc I5 is flexed upwardly and inwardly by the force of the well fluid passing up the tubing string II through the annular space between the inner wall of the tubing string and the outer edge of each disc as shown in Figure 3. This action is repeated throughout the pumping operation.

When the sucker rod string II is withdrawn from the well for repairs or other reasons, the discs I5 are suiciently flexible so that the speed oi withdrawal may be sucient to cause the uid force acting on the upper surface of each disc to iiex the disc downwardly, as shown in Figure 4,

thus forming a suiiicient annular space between the disc and the tubing wall through which the well fluid may pass.

I claim as my invention:

l. In a well pumping installation comprising a production tubing suspended in the well for conveying well iluid to the surface and a reciprocating-type well pump positioned in the lower end of tubing, the combination of a sucker rod string suspended within the production tubing, the lower end of said sucker rod string being aixed to the pump for reciprocating said pump in a vertical plane, and sand-trapping means secured to the sucker rod string above said well pump for catching sand settling in the tubing when the pump is not reciprocating, said sand-trapping means comprising substantially flat flexible disc means having an axial hole therethrough in which the sucker rod string may be positioned, said disc means extending transversely in said tubing and having a diameter substantially equal to the inner diameter of said tubing.

2. In a well pumping installation comprising a production tubing suspended in the well for conveying well uid lto the surface and a reciprocating-type well pump positioned in the lower end of tu'bing, the combination of a sucker rod string suspended within the production tubing, the lower end of said sucker rod string being afxed to the pump for reciprocating said pump in a vertical plane, and sand-trapping means secured to the sucker rod string above said wellv pump for catching sand settling in the tubing when the pump is not reciprocating, said sandtrapping means comprising substantially flat exible disc means, a short cylindrical throat section secured to lone side of said disc means. said disc means and cylindrical section having an axial hole therethrough in which the sucker rod string may be positioned, said disc means extending transversely in said tubing and having a diameter substantially equal to the inner diameter of said tubing.

3. Sand-trapping apparatus for use in a production tubing of an oil well produced by reciprocating a pump at the end of a sucker rod string, said apparatus comprising substantially flat flexible disc means having a diameter substantially equal to the inner diameter of the production tubing, and means for securing said disc means to the sucker rod string whereby said disc means extends transversely within said tubing to form a seal thereacross adapted to catch sand which settles from the well uid within the tubing when the sucker rod is not reciprocating.

4. Sand-trapping apparatus for use in a production tubing of an oil well produced by reciprocating a pump at the end of a sucker rod string, said apparatus comprising a plurality of substantially dat iiexible discs of a diameter substantially equal to the inner diameter of the production tubing, and means for securing said discs in spaced relationship on the sucker rod string .whereby said discs extend transversely within said tubing to form a seal thereacross adapted to catch sand which settles from the well fluid within the tubing when the sucker rod is not reciprocating, the outer edges of said discs flexing upwardly and inwardly on each downstroke of the pump to .permit the passage of well fluid thereby.

5. In a Well pump installation, the combination of a tubing string, a sucker rod string reciprocable therein, and a plurality of essentially flat disc shaped elements mounted on the sucker string transversely thereto and substantially spaced from each other, the diameter of said disc elements being slightly in excess of the internal diameter of the tubing string, and the vertical cross-section of said disc elements being attenuated away from the axis thereof, whereby the rim of each disc element is readily deflected upwards upon a downward motion, and downwards upon an upward motion of the sucker rod string by friction with the tubing string walls.

6. In a well pump installation, the combination of a tubing string, a sucker rod string reciprocable therein, and a. plurality of flexible discshaped elements mounted on the sucker string transversely thereto and substantially spaced from each other, said disc elements being formed with a concave upper face to support sand settling in said tubing string, the diameter of saidl disc elements being slightly in excess of the internal diameter of the tubing string, and the Vertical cross-section of said disc elements being attenuated away from the axis thereof, whereby the rim of each disc element is readily deflected upwards upon a downward motion, and downwards upon an upward motion of the sucker rod string by friction with the tubing string walls.

7. In a well pump installation, the combination of a tubing string, a sucker rod string reciprocable therein, centering guides aflixed to said sucker rod string in vertical spaced relationship, and a plurality of flexible disc-shaped elements mounted adjacent said centering guides on the sucker string transversely thereto and substantially spaced from each other, said disc elements being formed with a concave upper face to support sand settling in said tubing string, the diameter of said disc elements being slightly in excess of the internal diameter of the tubing string, and the vertical cross-section of said disc elements being attenuated away from the axis thereof, whereby the rim .of each disc element is readily deflected upwards upon a downward motion, and downwards upon an upward motion of the sucker rod string by friction with the tubing string walls.

WILFRED S. CRAKE.

References Cited in the iile of this patent UNITED STATES PATENTS Number

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