US2714500A - Impact drill - Google Patents

Description

Aug. 2, 1955 y R. E. sNYDER IMPACT DRILL 2 Sheets-Sheet l Original Filed March l5.I 1947 @oaf/W5 5M/r0.5@

INVENTOR.

BY Afro/aven Aug 2, 1955 R. E. SNYDER 2,714,500

IMPACT DRILL Original Filed March l5, `194'? V2 Sheets-Sheet 2 rrppN-K United States Patent O IIVIPACT DRILL 734,990, March application February 6, 1952, Serial Continuation of application Serial No.

15, 1947. This No. 270,189

6 Claims. (Cl. Z55- 3) My invention relates generally to impact drills, and more particularly to impact drills of the type in which a hammer member is reciprocably mounted on a shank, and is caused to impact against an anvil or other suitable means to thereby deliver a series of impacts to the bit. This application is a continuation of my co-pending application Serial No. 734,990, filed March 15, 1947, now abandoned.

In the drilling of wells, such as oil Wells, it has been found that the speed and general eflciency of the drilling operations may be greatly improved by the use of a drill in which the rotating bit periodically has impacts transmitted to it to force it into the formation being drilled. In my co-pending applications for Impact Drills, No. 527,179, filed March 20, 1944, now Patent No. 2,425,012, issued August 5, 1947; No. 674,526, tiled June 5, 1946, now abandoned, and No. 714,339, tiled December 5, 1946, now Patent No. 2,635,852 issued April 2l, 1953, I have disclosed new and improved types of rotary impact drills which are operated in this manner. Broadly, each of these drills is operated by a body which is rotatably mounted upon a rotary drill stem, and which is provided with Huid-engaging means so that relative rotation occurs between the body and the shank. The relative rotation is then used to operate driving means, such as cam means, to reciprocate the hammer. In general, the Huidengaging means of my previous drills have comprised radially extending blades or vanes having a substantial surface area which acts against the fluid in the hole when the drill is rotated about its longitudinal axis. When the blades are formed of a rigid material such as metal, there may be a tendency for the drill to hang up if projections are left in the wall of the well. Furthermore, with a rigid blade the same amount of blade surface is presented to the uid at all times regardless of the speed of the hammer body, and consequently the torque devel oped by the latter increases rapidly as the speed of rotation is raised. While this latter feature is under certain circumstances desirable, it is sometimes preferable to have the torque developed by the body and blades remain fairly constant as the rotational speed of the body is varied widely, and this may be done by designing the blade to yield under load. At all times it is desirable that the drill not hang up in the well, and hence any construction which reduces the possibility of this is quite desirable.

It is therefore a major object of this invention to provide an impact drill of the above-mentioned type which is provided with resilient fluid-engaging means which will pass over obstructions of the type sometimes encountered in wells, without jamming or hanging up thereon.

Another object of my invention is to provide such a uid drag body having blades which develop a torque varying within a narrow range as the rotational speed of the bady is changed between Wide limits.

It is a further object of my invention to provide a body of this type having blades which may be adapted to spread mud or similar material uniformly over the surface of the well wall with a troweling action to thereby smooth and seal the wall.

Still another object of my invention is to provide a resilient blade construction in which the damaging or injuring of one blade section does not necessarily weaken or damage the remainder of the sections.

It is a still further object of my invention to provide a blade structure which is economical to manufacture and which is designed to withstand the abuse and mistreatment it will normally receive in the eld, while still being quickly and easily replaceable should any damage occur.

These and other objects and advantages of my invention will become apparent from the following description of preferred and optional forms thereof, and from the drawings illustrating those forms in which:

Fig. l is a side elevational View of a drill constructed in accordance with my invention and installed in a well, a portion of the structure being broken away to show the details of construction;

Fig. 2 is a cross-sectional ure l;

Fig. 3 is a cross sectional view of one of the blade sections shown in Fig. 2, but enlarged to show its details of construction;

Fig. 4 is a fragmentary vertical View, similar to Fig. l, of the retarder body having a series of helically extending blades; i

Fig. 5 is an optional method of constructing the resilient blade sections;

Fig. 6 is a view similar to Fig. `2, showing the method of attaching the blades shown in Fig. 5;

Fig. 7 shows one method of providing a continuous reinforcing core for blade sections;

Fig. 8 is a side elevational view, similar to Fig. l, of a form of my device adapted to wipe the wall of the hole and spread mud thereon;

Fig. 9 is a cross sectional view taken at 9-9 in Fig. 8 to show the construction and operation of this embodiment of my invention;

Fig. 10 is a cross sectional detail of the construction of a blade and one method of attaching it to the body;

Fig. 1l is a fragmentary view similar to Fig. 9 showing the operation and results of the wall smoother type View taken at 2-2 in Figof blade; and

Fig. l2 is an elevational view similar to that of Fig. 8 showing how these blades may be attached to a body to provide helical instead of straight blades.

Referring now to the drawings and particularly to Figs. l to 3 thereof, the numeral 10 indicates a hollow shank adapted to be attached at its upper end to a rotary drill stem (not shown), and provided at its lower end with a coupling member 11 adapted to receive a bit 12. An outlet 13 is formed in the bit 12 near the cutting edges thereof, and drilling uid or mud is forced downwardly through the shank 10 and escapes through the opening to wash rock cuttings and detritus upwardly, around the outside of the shank, and to the surface so that the well is kept celan at all times and the bit is free to drill through the formation being cut. This procedure is well known, and the drill stem (not shown), the coupling member 11, and the bit 12 may be of any suitable type, of which there are many known in the art.

The various drills which I have shown and described in my previously mentioned co-pending applications rely upon the use of a hammer member which is reciprocably mounted upon the shank 10, and which is adapted to be raised and then dropped to impact against an anvil or cam by reason of the relative rotation between the fluid drag body and the shank. In my previously mentioned co-pending applications, various methods are disclosed i for transforming the relative rotation between the iiuid drag body or retarder and the shank 10 into reciprocatory motion ofthe hammer body, and one of the simplest of these methods is the form shown in Fig. 1, in which a driving cam 14 is rigidly attached to the shank 10, While a driven cam 15 is adapted to override the driving cam and to impact against the latter. The driven cam l5 may be rigidly connected to a bladed hammer body 16, and thus any rotation between the body and the shank 10 Will cause the driven cam 15 to be raised with respect to the driving cam 14 and then dropped downwardly to impact against the latter, the weight of the hammer body adding to the force of the impact. Regardless of the type of construction or method of operation which is used, however, the various impact drills disclosed in my previously mentioned co-pending applications rely upon a seriesof radially extending blades or vanes which are attached to the body 16 and extend outwardly therefrom to engage the drilling fluid or mud as it passes upwardly around the shank 10. The drilling uid, because of its viscosity, weightand similar characteristics, opposes the passage of the blades or vanes through the fluid, thereby acting as a drag or retarding force which slows the rotation of the body 16 with respect to the shank 10, thus effecting relative rotation between the cams.

In some cases, it may be desirable to rotate the shank 10 at a relatively high speed while keeping the rate at which the hammer impacts against the anvil at a ,relatively low value. If rigid blades are used, the impact rate will be increased as the speed of the shank 10 is increased, but if resilient blades are used, there will be a tendency for the blades to be folded back against the surface of the rotatable blade supporting body as the speed of the latter is increased. This folding back decreases the area of the blades which is directed against a drilling uid and consequently there is a tendency to limit the retarding torque delivered to the body. In this way, the speed of rotation of the body 16 with respect to theV shank 10 may be maintained within fairly narrow limits while the rotational speed of the shank varies between rather wide limits.

While various forms of resilient blade construction may be used, one very satisfactory form is shown in Figs, 1 to 3 where it will be seen that a number of individual blade sections 17 are grouped to provide a series of longitudinally extending vanes. Each of the blade sections 17, as indicated in Fig. 3, is formed of a T-shaped member attached to the body 16 so that the stem of the T projects radially outwardly therefrom. The cross bar or base of the T-shaped section 17 is suitably attached 1;

to the body 16, and a stiifener 20, preferably in the form of a wire or thin sheet core, is formed in the stern and the base of the blade section to provide increased strength for the latter. From the nature of the conditions under which this blade section is used, it will be apparent that the section must be capable of withstanding a large amount of abrasion, moisture, grease, oil, and shearing forces which would tend to tear the stem from the base. Most of these requirements are met by one or another of the synthetic rubbers, and consequently I prefer to form the blade sections 17 of a synthetic rubber with the reinforcing member 20 extending radially outwardly to a point considerably short of the end of the section. In this way, the reinforcing core 20 stiffens and strengthens the section 17 near its base, while leaving the tip relatively unrestrained so that it may be deformed in the manner previously described.

The radial distance which the stem of the blade section extends into the fluid is correlated with the size of the vell being drilled so that the blades preferably just miss the walls of the well. In this way, the maximum blade area is presented to the drilling fluid while the blades are not worn by constant rubbing against the wall of the well. The length of the individual blade sections 17, measured along the longitudinal axis of the body 16, may be of any convenient value, but is preferably relatively short so that damage to one of the sections will not require the replacement of more than that portion of the longitudinally extending blade actually damaged. lt will be apparent, of course, that the individual blade sections 17 may be combined intoV a single blade (not shown) should this be thought desirable, but normally the advantages to be gained from using the smaller sections will more than outweigh the advantages of using the longer sections.

Under certain conditions the possibilities of damaging one or more of the blade sections 17 is very great, and therefore it is desirable to be able to replace damaged sections with a minimum of eifort. Consequently, I have developed the method of attachment shown in Fig. 2 where it is seen that the retarder body 16 is provided with a series of longitudinally extending slots 21 adapted to receive the stem portion of the blade sections 17. These sections are inserted through the slots Z1 from the interior of the body 16, with the stem portion extending radially outwardly therefrom and with the cross bar portion bearing against the interior of the body. When all of the blade sections 17 have been inserted in the body 16, a liner 22 is placed within the body to bear against the innermost faces of the cross bars of the blade sections, holding the latter against movement and retaining them in the desired position. if desired, spacers 23 may be placed between the body 16 and the liner 22, extending between the adjacent longitudinal edges of the blade sections so that the latter are held against any horizontal or rotational movement. In this way, a very rugged construction is provided which will withstand the normal severe usage to which such equipment is subjected.

It is sometimes desirable to provide helical blades or varies for the fluid drag body instead of the straight longitudinally extending biades heretofore described and the method of mounting just described lends itself very well to this form of construction. As indicated in Fig. 4, the desired shape of the blades may be marked upon a body 16a and a series of slots then formed in the body.

following these lines. The blade sections 17 are then inserted through these slots, and the liner 22 is placed within the housing to hold the sections in this position. Spacers similar to the spacers 23 of the form shown in Fig. 2

may be used if desired, but it will be noted that these modified spacers must be inserted between'the adiacent longitudinally extending edges of the stern portions with a rotary motion so that the spacers are, in effect, screwed into the body 16a.

Where the construction of the body 16 is such to render it impractical to forni the various slots 21 therein and insert the liner 22, it may be found desirable to attach the blades to the exterior surface of the body. The type of blade shown in Fig. 3 may be attachedfin such a manner by placing the cross bar portion of the section in a metal enclosure which may be welded, riveted or screwed onto the body 1&3. Where the blade is to be Welded to the body 16, however, the heat of the welding operation may damage the rubber portion of the blade, and

* thereby change its strength. To overcome this diflicuity,

I have developed the optional form of construction illustrated in Figs. 5, 6 and 7 wherein a blade 17a is provided with a resilient stem portion 25, similar to the stem portion of the blade section 17, and likewise provided Y with a Stiffening core or wire 2d. At its innermost end, the thickness of the stem portion 25 is increased and the ends of the stiiener are bent outwardly to form the cross bar of the T-shaped section. A backing plate 26 is tackwelded or otherwise securely held to the cross bar portions of the core 20, and clamping plates 27 and 27a are attached to the cross bar section of the stitening member on the side of the latter adjacent the stem portion 25. These clamping plates 27 and 27a are thick enough to engage and securely hold the enlarged portion of the stem portion and, with the cooperating support of the stili"- ening core 20, form a rugged and secure holding member for the blade section 17a. It will be realized that the stem portion 25 may be bonded to the stilening core 20 and also to the holding plates 27 and 27a, but in most instances this is not necessary.

To attach the blade sections 17a to the body 16, the sections are placed in the desired positions on the body with the backing plate 26 against the body and the stem portion 25 extending radially outwardly therefrom, and the cross bar portion of the blade section is then welded around its edges to the body. A damaged blade section may be removed by applying a torch around the edges of the cross bar portion of the blade section, and a replacement section may then be welded in its place.

It will be realized that the use of the stiiening core 20 is not essential since somewhat similar results may be obtained by progressively increasing the thickness of the stem portion of the blade section 17 or 17a. The attaching means which may be employed with these thicker blade sections will vary with the particular form of blade section and whether it is surface mounted as shown in Fig. 6, or is inserted through the body 16 as shown in Fig. l. These various attaching means, of course, can and preferably will, be quite simple, and will be apparent to those skilled in the art.

Similarly, where the stiffening core 20 is used, its form may be varied to meet the requirements of the particular application. If relatively short blade sections 17 are used, similar to the type shown in Figs. 1 and 4, the

individual sections may be provided with their own L separate and independent stifening members. Individual sections designed for replacement will, of course, be constructed in this manner and the stiiening core 20 will generally be formed as a U-shaped member with its ends bent in opposite directions, perpendicular to the plane of the U. Where a series of individual sections 17 or 17a are to be joined together, or where a continuous type blade is to be used, the stilfening core 20 may take the form shown in perspective in Fig. 7. If this form of core is used for a series of sections, a damaged section may be removed by merely cutting the core 20 between the adjacent sections and releasing the cross bar portion from the body 16 in the appropriate manner.

While the use of discontinuous blades formed of a plurality of individual sections found preferable because of the economy and ease of replacement, it is sometimes desirable to use a continuous blade to secure some particular result. One such application is illustrated in Figs. 8 and l2, where I have illustrated how the resilient blades may be adapted to wipe the walls of the well and coat the latter with a layer of mud. The advantages of such a device will be appreciated when it is remembered that the walls, as they are cut by the drill bit, are relatively rough and offer a great frictional resistance to the upward flow of the drilling mud or fluid from the bottom of the well. Furthermore, where the walls are relatively porous, there is an increased opportunity for any iiuid within the well to escape therefrom and likewise for unwanted fluids to seep into the well. Consequently, it becomes a matter of some importance to provide a coating of a smooth, relatively dense material on the walls if the maximum etciency in the drilling of the well is to be obtained. It is to be understood, of course, that the mud layer is not intended to be a replacement or substitute for the casing which is customarily used 17 or 17a will generally be n i rubber.

6 When applied as a compacted layer to the walls of the well, however, the drilling uid or mud provides a surface having the desirable features heretofore mentioned, with the additional advantages that by forming this layer with my improved device about to be described, these advantages are obtained at a practically negligible cost.

In the form shown in Figs. 8, 9, 10 and 211, the numeral 10 indicates a shank adapted to be lowered into a well and rotated therein and the numeral 30 indicates a generally tubular body mounted on the shank and adapted to be rotated with respect to the walls of the well. The tubular body 30 may be the hammer body of one of my drills, and hence may be rotatable with respect to the shank 10 in addition to being rotatable with respect to the walls. However, rotation of the tubular body with respect to the shank 10 is relatively unimportant insofar as the presently described features are concerned, so long as the body is rotatable with respect to the walls, and thus the tubular member 30 may be rigidly connected to the shank 10 if this is found desirable.

Mounted on the body 3i) are a series of generally radially projecting blades 31 which extend along the length of the body and are formed of a resilient material such as The construction of the blades 31 is generally similar to the construction of the blade sections 17 of the previously described forms but whereas the previously described blades were purposely formed short enough to clear the walls of the well, the blades 31 are made of a suiiicient length to scrape against the walls and be turned backwardly by this movement. As indicated in Fig. l0, the tips of the blades 31 are preferably made quite thin to increase their ilexibility so that they bear against the wail with a iirm but resilient pressure. When the body is first lowered within a Well, only the tips of the blades 31 will bear against the wall, but later, as indicated in Fig. 11, the wall will become plastered with mud and a greater portion of each of the blades will be bent rearwardly to provide a greater wiping or trowel action. Because of the ilexibility requirements of such blades, I have found it generally unnecessary to provide any resilient stiifening material such as the core 20 of the blade sections 17, but such stiifening members may be used if necessary to increase the resilience of the blades or to increase their resistance to tearing.

A cross section of a blade 31 meeting these requirements is shown in Fig. 1i) wherein it is seen that the tip portion 32 is made considerably thinner than the remainder 0f the stem portion 33, while a cross-bar portion 34 is formed integral with the stem 33 to provide a T-shaped section similar to the section of the blade 17 previously described.

Generally, it is preferable to use a continuous type blade, such as that shown in Fig. 8, instead of a discontinuous blade such as that shown in Figs. l and 4, but where the discontinuous type of blade is used, it may be inserted through slots cut in the body 3i? and held therein in a manner similar to that shown and described in connection with Fig. l. However, where the continuous type of blade is used, the length of the slots necessary to accommodate a blade of this type is generally such as to weaken the tubular body 30 and hence I prefer to attach a continuous blade to the surface of the body in any one of several suitable manners.

As seen best in Figs. 10 and ll, one method of accomplishing this is to provide a metal fastening strip 35 adapted to iit against the tubular body 30, and having a pair of arms 36 and 36a adapted to lit around and engage the cross bar section 34 of the blade 31, while permitting the stem portion 33 to extend radially outwardly therefrom. The metallic holding strip 35 is preferably bonded or otherwise securely held to the blade 31 throughout the entire length of the latter, thereby providing a rm support which may be readily attached to the tubular body 30 whether this work is done in a shop or in the field. One

in such wells.

7 of the simplest methods of rigidly attaching the strip 35 to the tubular body 30 is to weld the longitudinal edges of the strip to the body so that a solid connection is quickly formed, while permitting the strip to be removed by the use of a torch which is generally available in the field.

In the operation of this device, drilling fluid or mud is forced downwardly through theV shank 10 to a point adjacent the drilling bit, where the mud escapes from the shank and is then forced upwardly around the outside of the shank, carrying with it the detritus formed at the bottom of the well. As the mud flows past the tubular body 39, the blades 31, which are rotating with respect to the wall of the well, force a portion of this mud against the wall, and the blades trowel or plaster it to form a smooth coating on the inside of the walls. As the thickness of the mud coating is increased, the blades 31 are bent rearwardly to compensate for this, and they therefore bear against the coating with a greater pressure, thus compacting the mud and forming a denser coating. While the effective diameter of the well is decreased by the coating of mud, the thickness of the coating is limited by the increased pressure of the resilient blades 31 thereagainst since this pressure will tend to wipe off some of the mud if the thickness of the coating becomes excessive. yIn this way, a sufficient area is always left for the passage of the mud upwardly through the well, while the roughness and the porosity of the walls is decreased to improve the drilling operation.

In Fig. l2, I have illustrated an optional form of my device in which the tubular body 30a is provided wtih helical blades 31a, the tubular body being mounted upon the shank 10 for rotation with respect to the walls of the well. If the tubular body 30a is rigidly connected to the shank 10 for rotation therewith, the helical blades 31a will tend to act as a pump to lift the fluid and drive it upwardly through the well. If the body 30a, on the other hand, is connected to the hammer member of one of my rotary impact drills, the upward flow of the fluid will tend to drive the blades 31a so that they rotate with respect to the shank. The advantages to be gained from this latter form of operation are discussed in my previously mentioned co-pending applications, and need not be repeated here.

From the foregoing it will be seen that I have shown and described a novel retarder member for rotary impact drills which will not hang up on projections within the well. This feature is further enhanced by the use of the Vwall wiper type of blade shown in Figs. 8 to l2, where the smoothing of the wall and the decreasing of its porosity i aid materially in the efciency of the drilling operation. l"

Furthermore, these drills have a certain torque controlling or limiting feature which can be used to great advantage in controlling the speed of impacting the hammer as the rotational speed of the shank 10 is changed.

While I have shown and described preferred and modified forms of my invention, it will be apparent that changes may be made therein without departing from the spirit of the invention as defined herein and I do not wish to be restricted to the particular form or arrangement of parts herein described and shown except as limited by my claims.

I claim:

1. A drill of the class described which includes: a shank adapted to be rotated in a well having drilling fluid therein; a body mounted on said shank for rotation with respect to the wall of said well, said body having a series of generally longitudinally extending slots therein; a series of T-shaped blades having resilient stem portions extending generally radially through said slots to engage said uid, said stern portions being of suflcient stiffness to develop a torque retarding the rotation of said body, and of sufficient resilience to pass over any obstacles of a type normally encountered in wells, said blades being progressively circumferentially deflected as said torque developed by their passage through said uid is increased;

and a liner Within said body bearing against the cross-bar portions of said T-shaped blades to hold said blades in place.

2. A drill of the class described which includes: a shank adapted to be rotated in a well having drilling fluid therein; a body mounted in said shank for rotation with respect to the wall of said well, said body having a series of generally longitudinally extending slots therein; a series of longitudinally extending T-shaped blades having resilient stern portions extending generally radially through said slots to engage said uid, said stem portions being of suicient stiffness to develop a torque retarding the rotation of said body, and of sutlicient resilience to pass over any obstacle of a type normally encountered in wells, and relatively rigid means within said body bearing against the cross-bar portions of said T-shaped blades to hold the latter in place.

3. A drill of the class described which includes: a shank adapted to be rotated in a well having drilling fluid therein; a body mounted on said shank for rotation with respect thereto and with respect to the wall of said well, said body having a series of longitudinally extending slots therein; a series` of T-shaped blades having relatively thin resilient stem portions extending generally radially through said slots to engage said uid but not said wall'of said well, said stem portion being of sufficient stiffness to develop a torque regarding the rotation of said body with respect to said wall when said shank is rotated, and of sufficient resilience to pass over any obstacle' of a type normally encountered in wells, said blades being progressively circumferentially deflected as said torque developed by their passage through said iluidV is increased; and a liner within said body bearing against the cross-barportion of said T-shaped blades to hold said blades in place.

4. A drill of the class described which includes: a shank adapted to be rotated in a well having drilling uid therein; a body mounted on said shank for rotation with respect thereto and with respect to the wall of said well, said body having a series of slots therein; a series' of rubber T-shaped blades having resilient stem portions extending radially from said body to engage said iluid and adapted to bear against said wall to make wiping contact therewith, said stem portions being of sufficient stiffness to develop a torque opposing the rotation of said body with respect to said wall when said shank is rotated whereby said body is retarded with respect to said shank, and of sufficient resilience to pass over any obstacle of a type normally encountered in wells; and a means within said body engaging the cross-bar portions of said T-shaped blades to hold the latter in place.

5. A drill of the class described which includes: a shank adapted to be rotated in a well having drilling fluid therein; a body mounted on said shank for rotation with respect thereto and with respect to the wall of said well, said body having a series of slots therein; a series of rubber T-shaped blades having relatively thin resilient stern portions extending radially from said body to engage said fluid, said stern portions being of sufficient stiffness to'develop a torque opposing the rotation of said body with respect to said wall when said shank is rotated whereby said body is retarded with respect to said shank, and of sutiicient resilience to pass over any obstacle of a type normally encountered in wells, said blades being progressively circumferentially deected as said torque developed by their passage through said iiuid is increased;

and means within said body engaging the cross-bar portion of said T-shaped blades to hold the latter in place.

6.v A drill of the class described which includes: a shank adapted to be rotated in a well having drilling fluid therein; a body mounted on said shank for rotation with respect thereto and with respect to the wall of said well, said body having a series of longitudinally extending slots therein; a series of T-shaped blades having resilient stem portions extending radially through said slots to engage said Huid and to bear against said wall to make wiping contact therewith, said stern portions being of suicient stiffness to develop a torque opposing the rotation of said body with respect to said wall when said shank is rotated whereby said body is retarded with respect to said shank, and of sufficient resilience to pass over any obstacle of a type normally encountered in wells; and liner means within said body bearing against the cross-bar portions of said T-shaped blades to hold said blades in place.

References Cited in the file of this patent UNITED STATES PATENTS Suman Aug. 23, 1921 Kennedy May 22, 1934 Bettis July 25, 1939 Sandstone June 27, 1944 Wright June 18, 1946 Snyder Aug. 5, 1947

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