US2503719A

US2503719A - Borehole washing device

Info

Publication number: US2503719A
Application number: US1618A
Authority: US
Inventors: Allen D Garrison
Original assignee: Texaco Development Corp
Current assignee: Texaco Development Corp
Priority date: 1948-01-10
Filing date: 1948-01-10
Publication date: 1950-04-11
Anticipated expiration: 1967-04-11

Description

April 1l, 1950 A. D. GARRISON BOREHOLE WASHING DEVICE Filed Jan. 10, 1948 WwVVVV/V/r//V/Vy//M//f///////MVVVV/VVMVVVVV Iii) y l INVEN TOR. A L5 GAR /5 N Patented Apr. 11, 1950 UNITEDfS-TATES PATENT oFF-ICE y i' B OREHOLE WASHING DEVICE Allen D. Garrison, Houston, Tex.', assgnor to .Texaco Development. Corporation, New York, N. Y., a. corporation. of Delaware f f Application January 10, 1948, Serial No. 1,618

This invention relates to washing devices for bore holes or wells, and more particularly to a device through the use of which a stream of washing fluid will be caused to pass through restricted areas or zones in intimate contact with the material which it is desired `to remove from the walls of the hole, such as drilling mud cake. The principal object of the invention is vto pro- ,vide a device of this kind which, when attached to the lower end of a string of tubing or drill pipe can be expanded to restrict -the annular space between the .tubing and the walls of the hole without the-necessity of valves orA other elements requiring control from the surface..

'Y As is well known, when drilling a bore hole a uid such as mud'is commonly; used for carrying the. cuttings upwardly to the surface. yAnother function of the fluid is yto plaster and to form a cake of the mud on the inner surfaces of the hole to prevent sloughing of the formation walls into the hole, to prevent water from filtering into the hole, etc. After'the casing has been set in the hole,vit is desirableto remove the mud cake from the walls of the oil bearing formation and this has frequently proven quite difficult.

Ithas been found that where gravel has been packed between the ow tubing and the walls of Athe producing formation, wateror other liquid forced downwardly to the 'bottom of the tubing string and then upwardly. through the gravel `pack tends towash the mud from the formation ywalls effectively, this being due to the fact that lthe restricted passages within the gravel and between the gravel particles and the walls of the iformation increase the velocityv of the liquid. Obviously when the water issuing from the lower end of the tubing string is permitted to pass upwardly through an annular space as large as that between the tubing and the walls of the hole the Velocity is'greatly reduced and much of the water does not come in contact with the mud cake with sucient velocity to remove the mud. f

In accordance with this invention an expansible balloon-like member is aixed to the lower endl of a tubing or drill pipe string. with means for :maintaining the member normally in/it's'longit'udinally extended, horizontallycontracted position, When liquid is forced downwardly through the string a portion will pass outwardly at the bottom of the string and will then pass upwardly through the space between the walls of the hole and the retracted member. Another portion, however, will pass from the tubing string into 10mm. (ci. 16a-18) the member to cause it to expand laterally 55 Fig. 3.

2 v toward the walls of the hole andy this will concentrate the flow of the washing liquid pastthe mud cake, this restricted area being adjacent the mud cake on the formation walls. The outer surface of the expansible member is preferably provided with spines or other pointed elements ,which tend to penetrate the mud cake so as to break it up. lThe outer surface is also provided with a plurality of vanes or bames which engage the formation walls so as to hold the body of the expansible member in spaced relation to the lwalls without materially interfering'with theA ilow of liquid. Inthis manner the washing liquid passing outwardly through the bottom ofthe tubing string is forced upwardly through the vanes and spines so as to effectively wash the mud cake from the walls. The device can be lowered or raised in steps while beingretracted and expanded so that all of the surface ofthe formation walls will be cleaned of the mud cake, or it can be lowered or raised continuously while the washing fluid is flowing, for the same purpose. -For a better understanding of the invention reference may be had to the accompanying drawing, in which Fig, l is a Vertical sectional elevation showing the washing device in retracted position being lowered through the casing; 1;

Fig. 2 is a cross-section on the line 2 -of Fig. 3 is a View similar to Fig. 1 but showing the washing element in its expanded orcleaning position against the formation walls, and

Fig. 4 is a cross-section onthe line d-tof Referring to the drawing, a section of a bore hole I0 is shown as .provided with a casing I2 .cemented in place, as indicated diagrammatically at I4.- With reference to Fig. 3, the lower portion ofthe bore hole is illustrated as penetratingfa producing formation I6 and on the walls of the producing formation below the casing l2 is shown ca mud cake orlayer I8, the mud having been deposited during the drilling operation.

'A pipe string 20 which may be tubing, liner or drill pipe has attached to its lower endampipe section 22 having a few wall perforations 24 and a somewhat restricted opening 2l at its bottom. An expansible balloon-like member 26 of rubber or other flexible material and preferably somewhat elongated in shape is firmly attached at its upper end to the upper exterior of the pipe section 22 as by cementing to or squeezing between rings 28, threaded or welded onto the pipe. The lower end of the member 26 is shown as provided lwith an opening, the edge of which is disposed in a channeled ring member 30 adapted to slide loosely upon the exterior of the pipe 22. Within the member 26 and surrounding the pipe section 22 is a coiled compression spring 32 adapted to force the lower end of the member 26 downwardly, away from the upper end so that the member will be longitudinally extended and laterally retracted when the device is being run into the bore hole, as shown in Fig. 1.

The outer side surfaces of the expansible mem ber 26 are provided with a yplurality' of .spines or spikes 34 which may be of rubber, metal, or other suitable material. Disposed longitudinally along and in spaced relation 4about the exterior surface of the member 26 are a plurality of vanes or baiiles 36 which also may `be of rubber lor metal, the purpose of which is to hold the outer surface of the expansible member slightly spaced from the walls of the hole when the member is in Iits vexpanded position to prevent the member :26 from fpackingzoii the annular ispace. If the vanes 36 are yof rubber the-y may comprise continuous strips `extending up 4and down the sides ofthe fexpansible member. Ii, however, the vane's are of metal or other non-flexible material, they may be formed in a :plurality `of Ashorter sections Islightly separated fas indicated `by spaces 138.

As 'shown in Figures 1 and 2 when there is no 'iiu'id under pressure within the tubing '223, the

member '26 will remain .in its vlaterally contracted "positionvdue to the pressure exerted by the spring "32. In this position, 'the device can be easily run finto a cased hole as shown in Fig. l to Aa position -below the bottom Vof the casing as shown in Fig.13. Assuming that water is `used 'as vthe washiing fluid, this water being forced downwardly through the tubing string 20 will pass outwardly th-rough the 'bottom opening 27 and then upwardly as indicated bythe arrows 49 in Fig. V3.

At-the same time a portion ci the water will pass fbe compressed somewhat due 'to 'the vertical shortening of the expansible member. 'The studs, or spines, 34 will penetrate 'the mud cake I8 while the vanes 3S will come to rest against the walls of the formation "SG, thus maintaining a restricted annular space between the outer surface of the member 2i; and the formation walls.

"The spines ad andthe varies '36 willftend to break up the mud cake i3 and will also provide some 1 turbulence of flow of the wash water inpassing "upwardly around the sides of the expansible member. 'In this manner the mud cake will be fqu'ickly and completely removedfrom Ythe forma- -f-'tion walls, the removed mud flowing upwardly f1 to the surface with `the returning wash water. 'If vdesired the vanes 35 may be disposed in a `spiral formation up and down 'the outer surface of the member "2li,

As stated hereinbefore, after a section of the -iformation wall has-been cleaned the tubing string 20 may be lowered or raised a distance equal 'to `.the expanded length of the member 25. In doing CII Lil)

"said valles and spines will enga-ge the walls 'the hole.

ascetic thisthe ow ofl water downwardly through the tubing 20 may be stopped, thus permitting the member 26 to return to its retracted condition afterv which it will again be expanded when the device has been raised or lowered to the next cleaning position. If desired, the member 26 may remain in its expanded position while the tubing 2li 4is moved continuously up or down along the formation walls, the spines 34 serving toabrade and scrape the mud cake from the walls at the same time the mud is being washed :away by the lupwardly flowing water.

Although the device has been described With particular reference to the cleaning of mud cake other uses will 'be'apparent For example, a similar expansible member may be disposed about the casing latsome point above the conventional cementing shoe. When expanded the cement would `be forced to the outside of the hole and by thus increasing the Velocity of the rising cement vslurry the wall of the hole would be cleaned of vmud cake lto 'insure a uniform bond of the cement `against the formation. In this instance the Ydevice would :in all probability be left in the `hole fafter'the cementing operation.

Obviously many rnomii'iications and variations of the invention, ashereinbefore set forth, may be vmade without departing from the Aspirit tand yscope thereof, -and therefore lcnly :suchllimitations lshould be imposed l.as 'are indicated in the apfpended claim.

I 'claimt A bore hole vwashing device comprising a string of tubing adapted to lbe lowered into 'said hole, the bottom end of said tubing being provided Nwith 'a ydownwardly directed opening smaller in diameter 'than Vthe interior of `said tubing, an ex. `pansible balloon-like member encircling said tub jing near its lower end, one end of said member being rigidly attached to said tubing and the other end having loose, sliding engagement with the outer surface of 'the tubing, a `plurality of nexible substantially vertical 'vanes projecting youtwardly 4from the /ou'ter surface fof said member, 'a plurality vci spines lalso projecting outward- '1y ifi-om the v'outer surface iof vsaid member ybe- #said last-mentioned opening into said lballoonlike member to expand it vhorizontally so that ldi ALLEN D. fCSQXRRISOIVi REFERENCES CITED The following references are of record in the 4nie oi "this ipatent':

UNITED `STATES PATENTS