US1778830A - Casing-centering device - Google Patents

Description

Oct. 21, 1930. H..R |RV|NE 1,778,830

. CASING GENTERING DEVICE Filed June 18, 1927 & 7 f l Q f :o oI E.) o 4 .l /v /5 5/ d @VWL/ .mw-:NTMV Hansel/ELL R In VIA/5,

Patented Oct. 21, 1930 UNITED STAT-Es HERSCHELL R. IRVINE, F LONG BEACH, CALIFORNIA cAsINe-CENTERING -nnvrcn pplication led June` 18, 1927. Serialiy No. 199,689.

In the drilling of deep wells, particularly with rotary drilling tools, it is extremely difficult to drill a straight hole. That is on encountering a hard stratum the hole will gradually veer 0E at an angle from the vertical, and the resulting angularity of the hole is sometimes very pronounced. When itis necessary to cement .the well to provide a water4 shut-oli', casing is set in the hole and cement is poured around the same to a considerable depth and when the cement sets it is impervious to water and prevents the'water from passing upwardly into the oil strata. It is obvious that in order to provide a tube water shut-olf, the casing should be centered in the hole in order that the cement may pass en tirely around the same. Due to the angularity of the hole, as above stated, it frequently occurs that the casing will rest against one side of the hole, thus preventing the cement from passing entirely around the same and it defeats the purpose of the cement, namely, a

complete water shut-oil. v

An object of 'my invention is to provide a casing centering device which will effectively hold the casing in the center of the hole at the time cement is poured, thus insuring that the cement will pass entirely around the casing and will provide a complete water shutolf. v v

Another object is to provide a casing centering device which yieldably engages the side of the hole, thus insuring that the casing will be centered.

Other objects, advantages, and features of invention may appear from thev accompanying drawing, the subjoined detailed description, and the appended claims.

In the drawing: t

Fig. 1 is a side elevation of my centering device in position on a section of casing.v

Fig. 2 is a sectional view taken on line 2,2, Fic. 1.

Fig. 3 is a sectional view taken on line 3,

.45 3, Fig. 1.

Fig. 4 is a side elevation of one of the sliding collars. v

Fig. 5 is a side elevation of the split sleeve. 5o Referring more particularly to the drawing:

The numeral 1 indicates the bore made by the drillingtool and 2 the casing which is set in the bore. The casing 2 is of considerably less diameter than the bore so that a space is provided in which the cement may be poured.V My centering' device 3 is positioned `on the casing at any desired position, preferably adjacent the bottom thereof, although a plurality of my devices may be positioned on the casing at intervals. A sleeve 4, which is preferablysplit, is secured to the casing 2 by welding, or otherwise suitably securing the same thereto, and this sleeve acts as a. stop for my centering device, as will be further described.

My centering device 3 comprises an upper and lower collar 5, `6, respectively, which collars encircle the casing and are slidable thereon. The collars 5, 6 are positioned on either side of the sleeve 4 and are adapted to en- 70 gage said sleeve, thus limiting the movement of the centering device on the casing.

A plurality of outwardly bowedv spring arms 7 extend between and are secured to the collars 5,6. These springs arms are preierably secured to the collars by passing the ends thereofinto dove-tailed grooves 8 in the collar, and then welding vor otherwise suitably securing the spring arms in the grooves. The spring arms 7 being bowed out- 80 wardly engage the side walls of the bore 1 thus holding the casing 2 accurately in the center of the bore.

In moving the casing upwardly or down-y wardly in the bore, the collars 5, 6 will slide 85 until they engage the sleeve 4, and after a constricted portion of the bore is encountered the spring arm 7 will compress because of the movement of the collars, thus permitting the free passage of the casing without any hindrance from my centering device.

In this connection it is important that the stop or sleeve 4 must be located between the upper and lower collars 5 and 6 respectively.

If the stopwere not located between the collars, but were located outside the collars, the action of thespring arms 7 in passing through constricted portions of the bore would not be nearly so satisfactory. To illustrate this,

let us assume that the stop is located between the collars, which feature in fact is the main point of this invention. With this arrangement, when the casing 2 passes downward through the well on its way to the location Where the cement shut-olf is to be made, restricted portions of the well are frequently encountered. At these places the spring arms will usually hesitate because of the constriction, the pipe or casing 2 will slide downward through collars 5 and 6. until stop 4 abuts against the lower collar after which the further descent of the casing will pull the spring arms 7 downward and easily and neatly collapse them to pass through the restriction. On the other hand if the casin and centralizer had been set far down `in the well` and for some reason it was desired t0 again raise itout of the hole before cementing, the same action as above described would occur, butin reverse order. That is. when thev spring arms 7 on the rising structure again reach a restricted portion of the bore, consisting .perhaps of a boulder, partial cavein, or some other circumstance, the restriction would hold the spring arms against further'ascent until casing 2 slid sufficiently through collars 5 and 6, so that stop 4 would come in contact with the upper collar 5, after which the further ascent of the casing will pull the spring arms 7 easily and neatly upward through the restricted bore, these spring arms freely collapsing to pass the restriction. The spring arms however pass the restriction so nicely, both during ascent and descent,

only because they are in both cases pulled and .not pushed through the restricted portion of the well. VIf they were pushed, instead of pulled, as infact wouldoccurif the stop were located beyond the collars, instead of between them` then on encountering` the restriction there would beasubstantial possibility that the spring arms instead of folding nicely to pass the restriction, would in fact belly outward, and -if this occurred the further forcing or pushing against the spring arms would drive them out into the formation and tend to snap them from the collars,

i thereupon allowing them to fall ahead of the centralizer into the bottom of the hole. This would be a serious diiculty, the possibility of which all practical well drillers are constantly on guard to prevent. If such a spring arm, being made of hardened steel, should fall to the bottom of the hole prior to ceinenting, it would be'there cemented in place.

and subsequently when the cement seal is drilled through to continue the drilling of the well to lower strata, the bit would encounter this steel spring, the edge would immediately be taken ofi' the drill, and a situation Would result which would either involve considerable delay inendeavoring to mill up this buried spring, or else in extreme cases the hole might have to be junked and abandoned because of impossibility of drill the casing, a

ing past the obstruction which this stray spring would set up. In the latter case the loss to the owners of the well would be very great, so great in fact that the possibility of its occurrence would usually deter them from using a cement equalizer wherein the possibility of the spring tearing loose, would be noticed. The service and conditions which such a cement equalizer must stand up against is much greater than the service required of an ordinary sucker-rod guide, or other ordinary types of guide, for the reason that the latter are used. only after the drilling of the well is completed, and if a spring g should tear loose from them, it would be of little consequence because no further drilling 1s to be done beyond the place where they would fall. i l

It is a further important feature of this invention, as set forth by the drawing, that the stop sleeve 4, located between the slidable collars 5 and 6, should be of smaller outside diameter than the outside diameter of collars 5 and 6. In fact it is preferable, as shown by Figure 1, that the combined thickness of the stop sleeve and spring arm should not eX- ceed the thickness of the slidable collars `5 and 6, the object being that when the equalizer 1s pulled through a very tightplace inthe well, the spring arms can fold flat and flush against sleeve 4, requiring no greater hole clearance to pass through than is required by collars 5 and '6. This is very important, because diameter is expensive in deep holes, and no projection beyond the surface of the pipe, of more than an `irreducible minimum can be tolerated.

In practice, I find it desirable to keepthe outside diameter of my slidable collars 5 and 6 equal to or smallerthan the outside diameter of the ordinary casing couplings, which those skilled in the artunderstand are used V:for screwing the successive joints of casing together.` This insures that my centralizar Will pass through any restriction that the strin of casing would itself pass through with its usual couplings between sections.

Having described my invention, I claim:

l. Av casing centering device comprising upper and lower collars slidably mounted on stop for said collars, said stop being located between the upper and lower collars, and a plurality of spring arms secured to the upper and lower "collars, said arms being adapted to engage the side of the hole to hold the casing in the center thereof.

2. In combination, a pipe adapted 'to be lowered or raised in a well, and a centralizery on said pipe, said centralizer comprising upper and lower collars and spring arms, both said collars embracing said pipe and being slidable thereon, and said pipe having a stop located between said collars and being adapted to prevent the sliding of said collars past said stop so that whether said pipe is raised or lowered through said well said spring armsr will always be pulled and not pushed through any restricted portion of said well.

3. A casing centering device rcomprising upper and lower collars adapted to slidably embrace the casin av plurality of spring I arms secured to sai upper and lower co lars, and a stop sleeve adapted to be secured to the casing between said upper and lower collars to arrest the sliding movement of said collars, the outside diameter of said stop sleeve bein smaller than the outside diameter of sai collars.

4. A cement equalizer com rising a piece of pipe adapted to be lowered) or raised in a well, two cylindrical end members slidably mounted on said pipe, spring arms fastened to said end members, said pipe having a stop located between said end members adapted to prevent the sliding of said end members past said stop so that whether said pipe is raisedv or lowered throu h said well said sprin arms will always ulled and not pushe through any restricted) portion of said well.

5. A cement equalizer comprising in combination with a piece of pipe, u per and lower cylindrical end members a apted to slidably embrace said pipe, a plurality of Aspring arms secured to said upper and lower end members, and a stop collar adapted to be securedto said pipe between said upper and lower end members to arrest the sliding movement of said end members, the outside diame- 'ter of said stop collar bein smaller than the outside diameter of sai cylindrical end members.

In testimon whereof, I aix my si PIERSCHELL R. IR

ature.

Images