US2362403A - Means for cleaning well screens - Google Patents

Description

Nov. 7, 1944. J. M. REYNOLDS MEANS FOR CLEANING WELL SCREENS Filed sept. 22, 1941 Patented Nov. 7, 1944 4'on the line 3 3 vof lFigure `1.

I MEANS FORGLEANING'- WELLSCR'EENSI 4 JohnM. zReynolds, Shreveport, La., vassigner to 2 Claims.

K Vrpha E. Reynolds, Shreveport, '-La. l .Application-.september 22, -1941, -seria1.N0.-411.81o l (Cl. T66- 20) This invention relates rto means .'-for cleaningv well screens.

.Anobjectfof the inventioni's to provide a novel means for cleaningvvell .screens rwhile located rin the well.

Another object fof the :invention 'is to provide means :for alternately Aremoving liquid "from 1 within -a 4.we'll screen :and athen" introducing liquid into fthe Vwell -screen `.to-thereby :the pres- -rsure acting on the screen todislodge particles in :the screening Vportions of it-he well zscreen.

-A further fobiectfof :the invention is to provide means E*for cleaning a vwell'fscreen :suspended in a well bore .by Aa .tubing :which comprises a -tu'bu-r Vlar member insertable into thetubing, yairpuxnp at the lower end ofthe .tubular member, a packer at'the -lower end of thetubular member to -form Ia seal between the tubular member and ythe screen, ltheipump having yan outlet through the tubular member :above fthe seal 'whereby viiuid may be removed from within-:the screen Cand tubular member by the pump, and then ui'd may be introduced into .the .screen `under :pressure by means-of the tubulari'member. .f o

acidizingas The inventionm'ayzalso be used for well as for cleaning a well. l. g

With l,the yabove and 'other objectsl 5in view 'the rinvention has particular relation to certain novel features of construction, operation and arrangement of parts, an "examplefof whichis given :in this specification and -illustrated in lthe `accom panying drawing; wherein:

Figure `1 rs'hows a longitudinal sectional view rof the `pump used inthe apparatus.

Figure :2 shows `a transverse fsectional view taken on the line 2-2 of Figure' 4. l i :Figure 3 shows ra .transversersectional view taken Figure 4 shows :a flongitudinal rsectional"view :of the apparatus inserted ina well screen, and

Figure 5 shows another embodiment of the'ity-pe -o'f pump, or -bailenemployed Referring Vnow more particularly to theidrawing wherein like numerals. `of reference designate -Lsimilar 'partei-n each'of l'the iigures, the nu- 'meral I designates a wellltubing 'to vthe'loweren'd of which is connected aiconvention'al l.well .screen 2, which has narrow 'slits f3 .through 'which -liquid may yenter into the `well screen. The y"lower lend 'of thewell screen 4is 'closed by 1a threaded'plug.

' clogged `with sand rand fdirt, no liquid can flow out of the well-bore into "the screen and .also ino liquid Acan fiowinto ythe well bore fromth'e lscreen. The screen and tubing 4form no part 'of `ethe invention and are merely shown ito explain the yuse of the invention.A

within the tubingy l lis a pipery which `is inv Vserta'bIe downwardly 'into the Itubing and with- `roff Ithe 4pipe i5. is -a packer which comprises the resilient sleeve 6 which is held -on the pipe '5 .by means of ysupporting 'rings 1,y 1, the .packer forming aseal "between vthe tubing adiacenti-he screen andthe pipe 5. Dii'erent ltypes of packfers may 'be used depending upon the construc- .tion of .thef'screen Within ithe lower .vend of :the

- :pipe i5 :arethe rsupporting wings 8, .8 which supnsubstantialrclearance is provided fbetween the drawable upwardly therefrom. At the lower end "i3" portpthe pump barrel `9 within the -fpipe 5.

The :pump,y a form of which is clearly illustrated :in vFigure 1, comprises :the `.tubular barrel 9 which vis closed atI its lower end fby the flap `valve Izl'iy which opens "upwardlyto fallow enf trance of Yuid in to rthebarrel. The-1owerend of the barrel yalsoha-s aside-openingeii which is ,closed Yby ythe .semi-cylindrical f sleeve I :Ia rotatably mounted on the barrel. This .sidenopening is provided to allow sand-in Ithe-barrel `to be treadily removed to clean the pump after use.

The upper end of the ybarrel il) is closed b y a head `.eI/2,which is threadedintosaid barrel. This head has a central .axial :bore v9a lwhich lis -reduced i-n fdiameter at the upper end of the head 4as at .I2a and outwardly ared :at the lower -end tofform the tapered seat I3. The upper .end of the head .-has va gland lIII attached thereto. The- Ahead :has 4a lateral threaded -hole :I 5 therethrough 'communicating with the central bore `,9a. A short tubular nipple I6 Ais threaded into `'said hole'l in thefhead and extends lthroug-liuthe pipe 5 in sealing relation therewith. A check Avalve lI'I Nin theconduit-of the-nipple I6 i-s-'eiective toipreventnow of fluid `from outside of @the fpipe 5 .'into the head I2 through said conduit-but to allowcutflow of liquid. l

A piston rod-FIB is reciprocaible through the gland -I4 Vand head-I2, and terminates "at f'the :up-

iperend in 4an ,enlarged pointed knob il 9. Al cable with 'a `conventional fgrappling `tool on the end "thereof, fnot`shown,1maybe lowered 'through the pipe f5 to land ron thepointed :knob I9-, eng-aging 'therewith to reciprocate the piston rod'=I8. *The lowerendfof the pistonrod I'is enlarged to Iform 'ar-cap 2i :and ilares downwardly .from the Vrod fat -:2I), fbeingshaped to -cooperate with and t closely fagainstthe tapered seat EI3 inthe `head I2 "torclose lthe :upper endoffthe barrel. 'The ycap 2| r:is :smaller diameter than Ithe vinside diameter `ofthe:barrel 9 'and has afcentral hole Z2 therein,

with lateral Iports 23, "2.3 from the hole 22 through .the cap. Threaded into the hole 22 is a tubular piston rnandrelZA vwhich has a tapered seat at the upper end'thereoi :and a val-ve 2ty is refc'iprocable inthe hole 22 :and arranged to coopcrate with said 'seat '25. Loosely mounted on ythe piston imandrel'Z'lI are the rigid piston rings 2l, I2-"I-, 21 whose outside diameters are rsmaller than the `inside 'diameter 'of the barrel 9 so that a *piston rings Iand the barrel 19 toreduce Athe wear there is a flexible annular fin 2 Ia, forming a fin valve. In this type of the pump, upon movement of the piston upwardly, should the pressure inthe barrel 9 be greater than the pressure outside thereof, the liquid under pressure in the barrel can escape past the fin valve 2Ia and out ,past the back lpressure valve I'I; but when the piston reaches its upper position, as shown in Figure 5, the velocity of the liquid under pressure pass-- lng through the grooves 28 will be sufficiently high to force the margin of the iin valve 2Ia against the lower end of the head I2 thus closlng said passageways 28 and retaining the pressure in the barrel 9a.

Under certain conditions when the pump is removed from the well it is desirable that pressure be retained within the pump barrel 9 so that when the pump reachesthe ground surface, the sleeve valve IIa may be opened and the contents of the barrel 9 will be discharged by the pressure retained therein.

The tubingi and the pipe 5 extend to the -ground surface and are supported by a suitable tubing head having conventional valves and fittings (not shown) so that liquid may be selectively admitted to either the pipe or tubing, or

outside of the tubing between the casing or well walls and tubing. y

After the screen 2 has remained in the well for a considerable period of time, the slits will become clogged so tightly with grit and sand that no fluid will pass from outside of the screen to the interior thereof. In order to clean the screen without removing the same from the well bore, this novel apparatus and method can be used. The pipe 5 is lowered into the well with the pump located therein and a seal is formed between the lower end of the pipe and the screen 2 or tubing I supporting the screen by means of the packer. There is usually a considerable amount of liquid in the well bore inside of the screen and tubing I and outside the screen so that there is a high hydrostatic pressure within the well bore and screen. The liquid in the producing formation is also usually under high pressure. The liquid is then removed from within the screen and pipe by reciprocation of the piston in the pump. More particularly, a cable with a grappling tool is lowered into the pipe 5 which engages the pointed knob I9 so that when the cable is reciprocated, the stem I8 and plunger is reciprocated. In operation, the plunger will drop downwardly by gravity, fluid in the barrel 9 is displaced by the piston, the fluid passes through the tubular mandrel 24 and raises the check valve 26 off of the seat and passes through the ports 23, 23 to thereby allow the plunger to drop, the flap valve III meanwhile being closed vso that uid does not escape from the barrel 9. Then as the plunger is raised, the fluid intrapped therein is forced out of the upper portion of the barrel 9 through the axial bore II of the head and through the nipple I6 into the space beeween the pipe 5 and tubing I; and simultaneously the barrel is filled by liquid entering through the flap valve I0. The check valve I'I in the nipple prevents fluid from entering the head of the barrel so that upon down stroke of the plunger again, the barrel will not reduce the pressure within the screen; course overflow lines are provided at the tubing raise the hydrostatic acts with the tapered seat I3 or the iin-valve 2Ia co-acts with the lower end of the head I2 to close the upper end of the pump so that no pressure can escape through the pump. Liquid is then delivered into the pipe 5 at the ground surface until there is a large column of liquid standing in the pipe so that there is a high hydrostatic pressure within the screen. It can be noted by an inspection of Figure 2 that there is a passageway between the pump and pipe 5 to allow liquid from Within the pipe to pass to the screen. The liquid under hydrostatic pressure in the screen then acts to force the material clogging screen outwardly. 'I'he hydrostatic pressure inthe screen may be supplemented by pump pressure applied to the tubing at the surface.

The liquid again may be transferred from the screen and pipe, by means of the pump, into the space between the pipe 5 and tubing I to again Of head to allow liquid between the pipe and tubing to be discharged therefrom. These operations may be continued as long as desired and until the screen clogging material is removed from the screen.

The drawing and description are illustrative merely while the broad principle of the invention will be defined by the appended claims.

What I claim is:

1. A device of the character described for cleaning a screen connected to the lower end of a tubing in a well comprising a pipe in the tubing, a packer on the pipe forming a seal between the pipe and the tubing, a pump in the pipe arranged to remove liquid `from within the tubing beneath the packer and discharge it into the tubing exteriorly of the pipe and above the packer to reduce hydrostaticV pressure in the screen caused by liquid in the pipe, said pipe having a passage leading from above the pump into the screen beneath the pump and whereby liquid may be introduced from the pipe into the tubing to raise the hydrostatic pressure in the screen.

2. A device of the character described for cleaning a screen connected to the lower' end of a tubing in a well comprising a pipe adapted to be lowered into the tubing, a packer on the pipe adapted to form a seal between the pipe and the tubing, a pump in the pipe, there being a .passageway leading from the pipe above the pump into the screen beneath the pump, said pump being arranged to remove liquid from within the pipe and screen and discharge it exteriorly ,of the pipe into the tubing above the packer to reduce hydrostatic pressure in the screen caused by the weight of the liquid in the pipe, and means in the pump movable into active position to prevent outward flow from within the pipe through the pump whereby liquid introduced into the pipe will be retained therein to pressure within the screen. JOI-IN M. REYNOLDS.

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