US3240274A

US3240274A - Flexible turbulence device for well pipe

Info

Publication number: US3240274A
Application number: US438168A
Authority: US
Inventors: James R Solum
Original assignee: B&W Inc
Current assignee: B&W Inc
Priority date: 1965-02-17
Filing date: 1965-02-17
Publication date: 1966-03-15
Anticipated expiration: 1983-03-15

Description

March 15, 1966 J. R. SOLUM 3,240,274

FLEXIBLE TURBULENCE DEVICE FOR WELL PIPE Filed Feb. 17, 1965 5 Sheets-Sheet 1 INVENTOR. 14/1455 ,6. 50.4 UM

BY K

3 Sheets-Sheet 2 J. R. SOLUM FLEXIBLE TURBULENCE DEVICE FOR WELL PIPE March 15, 1966 Filed Feb. 17, 1965 INVENTOR. JAMES e. .504 0/1// BY 7'? .4770Z/VEJ6 March 15, 1966 J. R. SOLUM FLEXIBLE TURBULENCE DEVICE FOR WELL PIPE Filed Feb. 17, 1965 3 Sheets-Sheet 5 P INVENTOR.

United States Patent 3,240,274 FLEXIBLE TURBULENCE DEVICE FOR WELL PIPE James R. Solum, Los Angeles, Calif., assignor to BdzW Incorporated, Torrance, Califi, a corporation of California Filed Feb. 17, 1965, Ser. No. 438,168 14 Claims. (Cl. 166-241) This is a continuation-in-part of my copending application entitled Flexible Turbulence Device for Well Pipe, filed Apr. 3, 1963, Serial No. 270,443, now abandoned.

This invention relates to a device adapted to be mounted on the exterior of a well pipe and positioned in a well bore for creating turbulence in the fluid flowing past the device in the annular space between the well pipe and the Well bore. In particular, this invention relates to such a device employing angularly positioned vanes for imparting a circumferential motion to the flowing fluid to thereby generate the desired turbulence.

As is well known to those skilled in the art, When a well pipe is positioned within a well bore and the drilling fluid is circulated in the annular space between the well pipe and the well bore, the drilling fluid may assume a channelling flow within the annular space. In this channelling flow condition only a portion of the fluid within the annular space is flowing relative to the well pipe and well bore and this flowing portion assumes and follows passages or channels formed within the remainder of the drilling fluid that is remaining relatively static. This formation of channels and creating channelling flow occurs as a result, at least in part, of the gelling properties of the drilling fluid or mud in that if the drilling fluid is allowed to remain in a static condition for a period of time it will gel and a substantial hydraulic or mechanical agitating force is needed to again return the entire column of drilling fluid to a flowing fluid state.

During many procedures and processes in the drilling and completion of a well, such as cementing a well casing in a well bore, this channelling flow is highly undesirable. For example, in a cementing operation if this channelling flow occurs, the cement slurry will follow these channels resulting in an incomplete displacement of the drilling fluid from the annular space. Under these circumstances the cement fill will be incomplete and probably inadequate to achieve the desired support and seal between the well pipe and the well bore. It has been found that hydraulic forces may be developed for eliminating this channelling flow by using extremely high fluid pumping velocities, but the pressures and volumes required have made such a method impractical due to the number of pumps required at the well site. The mechanical agitation forces necessary to return the gelled drilling fluid to a fluid condition have been accomplished by the use of scratchers, turbulence generating devices, and the like on the exterior of the well pipe and then rotating or reciprocating the well pipe to agitate the drilling fluid and cement slurry.

While most conventional scratchers will develop at least some agitating force for breaking down the gel condition of the drilling fluid, these scratchers also abrade the wall of the well bore which is sometimes undesirable Certain turbulence generating devices have been employed such as devices commonly known as spinners that have rigid metal fins projecting radially and extending longitudinally and circumferentiaily of the pipe. Theoretically, these spinners cause a swirling motion in the drilling fluid flowing past the spinner, but since the fins are rigid they necessarily must project radially a distance less than the actual annular space so that the spinner does not become stuck within the Well bore. Thus, there is always a portion of the drilling fluid beyond the radial 3,240,274 Patented Mar. 15, 1966 extent of the spinner fins that is not agitated and this portion may be relatively large at enlargened portions of the well bore. Further, unless the spinner is perfectly centered within the well bore, such as by an adjacent conventional centralizer, the spinner fins will engage and gouge one side of the well bore wall and become even more spaced from the opposite side of the well bore wall. This may be particularly objectionable in slanted wells in that the plurality of spinners that are conventionally placed on the well pipe may tend to gouge out a large portion of the well bore wall on the lower side. There have been attempts to provide rubber spinners but the extreme abrasive and force conditions encountered in a well bore usually cause destruction of the rubber fins before the desired functioning is achieved. Further the necessity of molding these rubber spinners with relatively thick fins to withstand some of the abuse and Wear results in producing a device which presents a substantial and objectionable reduction in the cross-sectional flow area in the annulae between the well pipe and the well bore wall.

Accordingly, it is a principal object of this invention to provide a novel form of turbulence generating device for use on a well pipe wherein stitfly flexible means impart a circumferential swirling motion to fluid flowing past the device.

Another object of this invention is to provide a novel form of turbulence generating well pipe device wherein a plurality of resiliently flexible metal vanes extend outwardly and circumferentially of the well pipe to circumferential divert fluid flowing longitudinally past the device in the annular space between the well pipe and a well bore wall.

A further object of this invention is to provide a novel form of turbulence generating device having a plurality of angularly extending metal vanes that extend outwardly to engage the Well bore wall and are resiliently flexible to thereby tend to conform to the configuration of the well bore wall for oflset positions of the well pipe.

Still another object of this invention is to provide a novel form of turbulence generating device having outwardly and circumferentially extending vanes that join the collar of the device at a longitudinal line whereby the vane is effectively hinged along this line for flexing and yet the vane is formed to impart circumferential swirling of fluid flowing past the device.

A still further object of this invention is to provide a novel form of turbulence generating device having flexible vanes for causing circumferential swirling of fluid that is relatively inexpensive to manufacture and sufiiciently rugged to withstand the adverse conditions encountered in a Well. A still further object of this invention is to provide such a device that is capable of being rigidly aflixed to the well pipe and yet remain undamaged by the flexing of the vanes.

Another and further object of this invention is to provide a turbulence generating device employing vanes for creating circumferential swirling of the fluid wherein such vanes will engage and mildly scrape the well bore wall without abrading or gouging the well bore wall.

A still further object of this invention is to provide a novel form of turbulence generating device employing resiliently flexible vanes that engage the well bore Wall to tend to center the well pipe within the well bore.

Another object of this invention is to provide a novel form of turbulence generating device which employs flexible metal vanes and is adapted to be mounted in combination with a conventional well pipe central-izer.

A further object of this invention is to provide a novel form of turbulence generating device comprising two halves hinged together for facilitating mounting on the well pipe and each half is economically constructed of a single sheet of metal with vanes stamped therefrom.

Other and more detailed objects and advantages of this invention will appear from the following description and the accompanying drawings.

In the drawings:

FIGURE 1 is an elevation view illustrating a well pipe positioned in a well bore with a plurality of the devices of this invention positioned on the well pipe in a typical manner.

FIGURE 2 is an elevation view of the preferred embodiment of the device of this invention installed on a well pipe.

FIGURE 3 is a sectional view taken substantially on the line 3-3 shown in FIGURE 2 and illustrating the device of this invention positioned in a well bore.

FIGURE 4 is a fragmentary sectional view taken substantially on the line 44 shown in FIGURE 2 and illustrating the configuration of the lower portion of the vane.

FIGURE 5 is an elevation view similar to FIGURE 2 and illustrating a modified for-m of the device of this invention.

FIGURE 6 is a sectional view of the modified form illustrated in FIGURE 5 and taken substantially on the line 6-6 shown in FIGURE 5.

FIGURE 7 is a fragmentary sectional view of the modified form of FIGURE 5 taken substantially on the line 7-7 shown in FIGURE 5 and illustrating a flexed position of a vane when the annular space at that vane is restricted.

FIGURE 8 is an elevation view similar to FIGURES 2 and 5 illustrates a second modified form of the device of this invention.

FIGURE 9 is a fragmentary sectional view of the modified form of FIGURE 8 taken substantially on the line 9-9 shown in FIGURE 8.

FIGURE 10 is a fragmentary sectional view similar to FIGURE 9 and illustrating the flexed position of a vane of this modified form when the annular space is substantially restricted.

FIGURE 11 is an elevation view similar to FIGURE 1 illustrating further embodiments of a device of this invention mounted on a Well pipe and positioned in a well bore.

FIGURE 12 is a sectional plan view taken substantially on the line 12-12 of FIGURE 11.

FIGURE 13 is a sectional plan view similar to FIG- URE 12 but illustrating the device positioned in a restricted diameter portion of the well bore whereby the device is partially collapsed.

FIGURE 14 illustrates a further modification of the embodiment shown in FIGURES 11 through 13 wherein the components are circumferentially oflset.

Referring now more particularly to the drawings, the device, generally designated 10, of this invention is adapted to be mounted on a well casing or pipe 11 that is to be positioned in a well bore 12. The device 10' may be secured to the well pipe 11 by any convenient means such as by welding the device directly to the well pipe or may be movable between a pair of collars aifixed to the well pipe, both of which arrangements are well known expedients for mounting devices on a well pipe. In the drawings, the device 10 has been illustrated as being affixed Iby weld 13 to a conventional stop collar 14 which is in turn, secured to the well pipe 11 at the desired location. The stop collar 14 may be of any conventional type such as that shown in United States Letters Patent No. 2,872,226, entitled Stop Collar For A Well Pipe. This manner of mounting device 10 is preferable only in that the necessity for welding on the well pipe 11 is obviated, the number of stop collars employed per device is minimized, and yet device 10 is rigidly secured to the well pi-pe.

In the preferred embodiment of this invention, the device 10 is comprised of a cylindrical collar 15 and a plurality of vanes 16 extending outwardly from the collar to generate turbulence in the fluid in the annular space between the well pipe 11 and the well bore 12. The collar 15 may be formed in any convenient manner such as form a flat piece of material rolled into a cylinder and seam Welded at 17. While device 10 is illustrated as having four vanes 16 it is to be understood and will readily appear to those skilled in the art that more or fewer vanes may be provided on different sizes of devices 10 or by varying the size of vanes 16. In this preferred embodiment the vanes are formed of the material of collar 15 and are integral therewith for both simplicity of construction and economy of manufacture.

The vanes 16 are each comprised of a trapezoidal shaped piece of the material of collar 15 cut or lanced along three

edges

17, 18 and 19 and bent outwardly along the fourth edge 20 of the trapezoidal shape. Opposite edges 17 and 19 are relatively parallel as shown, but it will readily appear that these edges may also be nonparallel thereby merely changing the final shape of vane 16.

Edges

18 and 20 are nonparallel and preferably spaced a larger distance at their upper extremities such that upper edge 17 is longer than edge 19. This size and orientation relationship of the edges of vane 16 may best be seen by considering the shape of the aperture formed in the material of collar 15 by the lancing out of the vane wherein

edges

17a, 18a and 19a of the collar aperture correspond respectively to the

edges

17, 18 and 19 of the vane. A flange 21 is formed in the vane 16 along the edge 18 and extends circumferentially to thereby form a surface for engaging the wall of well bore 12. The portion 22 of vane 16 between edge 20 and flange 21 is formed into a twisted rather than a flat surface. This relationship may readily be seen by considering FIGURE 3 wherein both the upper edge 17 and the lower edge 19 of vane 16 are visible and angularly positioned relative to each other and yet edge 20 appears as a point. The surface of portion 22 is everywhere positioned at an acute angle to a radius of collar 15 passing through edge 20 and the size of this acute angle increases as edge 17 is approached and decreases as edge 19 is approached. That is to say, portion 2 2 of vane 16 extends both outwardly and circumferentially from edge 20 on collar 15. By this predetermined relationship between the size and shape of vane 16 and the varying angle between portion 22 and the surface of collar 15, the flange 21 is substantially parallel to the surface of collar 15 and extends in both a longitudinal and circumferential direction with respect to the collar.

Thus it may be seen from the circumferentially and longitudinally extending orientation of portion 22 of the vane 16 that as well pipe 11 is lowered or raised in a well bore 12 containing drilling fluid or as drilling fluid is circulated in the annular space the vanes 16 will impart a circumferential swirling motion to the fluid flowing past the device.

Edge 20 of vane 16 extends longitudinally and substantialy parallel to the axis of the collar and therefore remains as a straight line when the vane 16 is formed into the heretofore described configuration. Since edge 20 is a straight line any inward force on a vane 16 will cause bending of the vane along edge 20 thereby simulating a condition as if vanes 16 were pivotally hinged to collar 15 along edge 20. Thus each of the vanes 16 will flex as an integral plate unit by flexing along the edge 20. In contrast it may be seen that if edge 20 did not extend longitudinally but rather somewhat circumferentially, as for example in the direction of edge 18a in FIGURE 2, the edge would be curbed and any vane extending therefrom would be substantially reinforced by such arrangement and therefore would necessarily be rigid and inflexible along such edge. The vanes 15 preferably extend outwardly from collar 15 a distance approximately equal to the theoretical distance between the well pipe and the Well bore wall when the pipe is centered. Thus, if the well pipe 11 becomes positioned off center toward a vane 16 that vane will be flexed inwardly rather than gouging into the Well bore wall. Moreover, this flexing will produce a resultant force tending to center the well pipe although the magnitude of such force will depend on the size, thickness and resiliency of the material selected for device 10. While various materials may be used for device as desired for producing varying attributes and properties of the devices, it is preferred that a sheet metal be employed that has, or may be heat treated to obtain, the resilient properties of a spring steel. By selecting such a material, the flexing of vane 16 as heretofore described will not result in permanent deformation or collapsing of the vane. Further more, it is preferred that the material of device 10 be compatible with conventional amnufacturing and forming techniques necessary to form the device. It has been found that sheet steel AISI No. 4130 or a thickness of .030" is satisfactory for obtaining most of the aforementioned properties.

Although it is not essential it is preferred that the longitudinal ends of flange 21 at edges 17 and 19 be slightly rounded as at 23 so that the flange does not gouge the wall of the well bore as the well pipe 11 is raised or lowered with respect to the well bore. This rounded portion at 23 also promotes ease of movement of the device relative to the well bore and reduces the possibility of damage to the vane 16 by edge 17 or edge 19 catching on the Wall of the well bore.

Referring now to the modified form of the device of this invention illustrated in FIGURES 5, 6 and 7 and generally designated 10b, it may be seen that device 1% is also comprised of a cylindrical collar b and a plurality of vanes 1611 similar to device 10 heretobefore described. Collar 1512 may also be secured to a conventional stop device 14b which is in turn secured to the casing 11. In this modified form the vanes 16b are separate components rather than be integral with the collar and are secured to collar 15!: by any convenient means such as spot welding 30. The vanes 16b may also be formed from a generally trapezoidal shaped piece of material having edges 17b, 18b, 19b and 20b with a base flange 31 of any desired shape as in integral part of the vanes 1612 along edge 20b. Therefore, in this modification as in the preferred embodiment, edge 20!) is merely a line where the material is bent rather than being an actual cut edge. Thus, the description, orientation and functions of edges 17b, 18b, 19b and 201) are substantially the same as heretofore described

edges

17, 18, 19 and 20, respectively. Vane 16b is provided with a portion 22b adjoining edge 20b that is formed into a longitudinally and circumferentially extending twisted surface similar to heretofore described surface 22.

However, in the modified form of this invention illus trated in FIGURES 5, 6 and 7 an inwardly curved flange 21b is provided and extends between portion 22b and edge 1817 rather than the fiat flange 21 shown and described with respect to the preferred embodiment of FIG- URES 2, 3 and 4. The curved flange 21b has the advantage of presenting a more even surface contact with the wall of the well bore 12 in all of the various positions that the vane 16b may assume upon flexing of the vane. Thus. it may be seen as illustrated in FIGURE 7, that when a vane 16b is flexed inwardly by urging same against a well bore wall, a surface contact between the vane and the well bore wall is still maintained whereas the vane 16 of the preferred embodiment would probably assume a line contact with the well bore Wall along the line joining flange 18 and portion 22. Moreover, it may be seen that with curved flange 21b the edge 18b is always slightly spaced from the well bore wall thereby further reducing the possibility of gouging the well bore wall. The longitudinal ends of flange 21b may be rounded as at 23b similar to the rounded portion at 23 of the preferred embodiment. This modified form further illustrates that the angle between free edge 18!) and longitudinal edge 29b and in turn the angle of the circumferential flow induced in the fluid may be different and substantially greater than that shown for the preferred embodiment. Moreover, it may be seen in FIGURE 6 that surface 221) may be twisted to such a degree at the upper extremity there of that edge 17b is nearly or actually tangent to the surface of collar 15b. In such an embodiment, the edge 17b is relatively long in order to extend a sufficient distance to engage the well bore.

It is also to be noted that this modified form of FIG- URES 5, 6 and 7 and also the hereinafter described modified form of FIGURES 8, 9 and 10 are constructed of a plain cylindrical collar and attached vanes which may be an advantageous mode of construction under various circumstances. For example, if a relatively large centering force by the vanes were desirable then the vanes could be comprised of thicker and higher alloy spring steel than is needed for the collar.

In the second modified form of this invention illustrated in FIGURES 8, 9 and 10, a plurality of vanes 16c are mounted on a cylindrical collar by any convenient means such as spot Welding 30c similar to the assembly of the modified form of FIGURES 5, 6 and 7. Again, a conventional stop collar He may be provided and secured to collar 150 by any convenient means such as welding 13c, the stop collar 140 being in turn secured to the well pipe 11 in a conventional manner. The vanes are again formed of a generally trapezoidal shaped piece of material having edges 17c, 18c, 19c and 20c substantially the same as edges 17, 18, 19 and 20 of the preferred embodiment and edges 17b, 18b, 19b and 26b of the first modified form, all respectively. Vane 16c is also provided with a base flange 31c substantially similar to base flange 31 of the first modified form. Vane 160 has a portion 22:: formed into a longitudinally and circumferentially extending twisted surface similar to portions 22 and 22b heretofore described. Rather than being provided with a straight flange 21 or a curved flange 21b, as heretofore described, this second modified form is provided with a well bore wall engaging surface extend ing substantially circumferentially from the outer extent of portion 220 and an inwardly extending support flange 33 between edge 1&- and surface 32 Support flange 33 may be relatively flat but extends both in a longitudinal and circumferential direction as well as being positioned at an angle -to the surface of collar 15c. Edge engages the outer surface of collar 15c and is preferably curved as shown to generally conform to the surface of collar 150. By this arrangement it may be seen that surface 32 engages the wall of the well bore and as the vanes 160 is flexed inwardly, the portion 22c and support flange 33 tend to become flattened as may be readily seen by comparing FIGURES 9 and 10. The flattening of support flange 33 requires a certain amount of additional lateral force that would not be required to flatten a vane not having such a support flange and therefore the vanes 16c tend to maintain the well pipe 11 in a more centralized position within the well bore 12. Moreover, it IS to be noted that support flange 33 extends circumferentially as well as longitudinally and, therefore, presents another surface tending to cause circumferential swirling of fluid longitudinally past the device 100.

The device of this invention may be provided with a relatively long collar such as that shown for device 10a in FIGURE 1 and be positioned between the spaced col- Iars 4t and 41 of a centralizer having outwardly bowed springs 42 extending therebetween. In this manner the conventional stop collar device 14d provided with device 10d also serves as a stop device to limit the movement of the centralizer along the well pipe as is generally desired. The springs 42 of the centralizer tend to retain the well pipe 11 centered in the well bore and, therefore,

enhances the etfectivness of device d as well as reducing the possibility of damage to the vanes of the device.

In the next modified form of this invention illustrated in the upper portion of FIGURE 11 the device, generally designated lite, is constructed of two

semi-cylindrical half collars

50 and 51 joined by hinges 52. The vanes 16c may be constructed in a manner similar to that described for the construction of vanes 16 wherein a trapezoidal shaped portion of the material of the collar is lanced from the collar to form the integral vanes. This hinged construction simplifies mounting of the device 10:: on the well pipe 11 as is well known to those skilled in the art. Although it is not essential to the construction of this embodiment, the device itle is illustrated as being mounted in a somewhat different fashion by positioning the device between a well pipe collar 9 and any conventional type of stop collar 8 mounted on the well pipe. This permits some sliding motion of the device 10c along the well pipe such as for accommodating the small reciprocating movement involved in connecting and lowering each additional joint of well pipe into the well bore.

In the next modified embodiment of this invention illustrated in the lower portion of FIGURE 11 and FIG- URES 12 and 13, the device, generally designated 10f, may be substantially similar to the first described embodiment of the device. The vanes 16f may be integrally formed from the material of the collar by lancing out trapezoidal shaped portions of the material. Instead of connecting the device 10 to a collar the device may be connected by a plurality of straps 6!) extending longitudinally between the device and one collar 61 of a conventional centralizing device, generally designated 62. Centralizer 62 includes the collar 61, an axially spaced collar 63 and a plurality of longitudinally extending and outwardly bowed spring staves 64. It is preferred that the staves 64 be circumferentially aligned with each of the vanes 16 whereby the vanes are retained within and protected by the staves 64. In this manner the resilient vanes 16 also serve to add support to the centering spring staves 64. Thus, as illustrated in FIGURE 13 the staves 64 and vanes 16 collapse and expand together as the device encounters variations in the diameter of the well bore. A further modification is shown in FIGURE 14 wherein the vanes 16 are positioned between the staves 64 whereby the vanes directly contact the well bore wall between the staves. This has the added advantage of presenting a more complex configuration in the annulae as is obvious from a comparison of FIGURES 12 and 14 whereby a greater turbulence will be imparted to drilling fluid flowing past the device. It is also to be noted that the conventional stop collar device 14] is not connected to device 10f but rather is positioned between the device and the upper collar 63. By this mounting arrangement the centralizer 62 is pulled along the well bore by the leading collar 61 or 63 depending on the direction of movement of the well pipe 11.

Thus, it may be seen that by this invention there is provided a device which is adapted to be mounted on the exterior of a well pipe for causing circumferential swirling of fluid flowing past the device and yet the device only resiliently engages the wall of the well bore. This resilient engagement of the well bore tends to avoid gouging of the wall of the well bore, promotes more uniform conformance to the actual shape of the well bore, and tends to resiliently center the well pipe within the well bore. These devices may be placed in any desired combination and/or spacing along the length of the well pipe to generate the desired turbulence at intervals along the well pipe.

Having fully described my invention it is to be understood that I do not wish to be limited to the details herein set forth or to the details illustrated in the drawings, but my invention is of the full scope of the appended claims.

I claim:

1. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of stiff vanes on said collar extending outwardly at an angle to the surface of said collar and being resiliently flexible relative to said collar along the juncture of the vane with the collar, and each said vane extending longitudinally and circumferentially relative to said collar for circumferentially swirling fluid flowing past said vane.

2. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of stiff vanes on said collar extending outwardly into the annular space, each said vane positioned at an acute angle to the surface of said collar and being resiliently flexible relative to said collar along the juncture of the vane with the collar for contacting the well bore and flexing inwardly as a unit upon movement of the well pipe toward the well bore, and each said vane extending longitudinally along and at an angle to the length of said collar for circumferentially swirling fluid flowing past said vane.

3. In a device for generating fluid tuburlence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of stiff vanes on said collar extending outwardly into the annular space, the outermost extent of each said vane having a generally circumferentially extending surface portion for making a surface contact with the well bore, each said vane positioned at an acute angle to the surface of said collar and being resiliently flexible relative to said collar along the juncture of the vane with the collar for flexing inwardly as a unit upon contacting the well bore during movement of the well pipe toward the well bore, and each said vane extending longitudinally along and at an angle to the length of said collar for circumferentially swirling fluid flowing past said vane.

4. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of stiff vanes on said collar extending outwardly into the annular space, the outermost extent of each said vane having a circumferentially curved portion for engaging the wall of the well bore, said curved portion having the circumferential extending free edge spaced inwardly from the well bore wall, each said vane positioned at an acute angle to the surface of said collar and being resiliently flexible relative to said collar along the juncture of the vane with the collar for flexing inwardly as a unit upon contacting the well bore during movement of the well pipe toward the well bore, and each said vane extending longitudinally along and at an angle to the length of said collar for circumferentially swirling fluid flowing past said vane.

5. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of vanes on said collar extending outwardly into the annular space, each said vane having a first portion joined to and extending at an angle to the surface of said collar, each said vane having a second portion joined to the outer extremity of said first portion and extending inwardly at an angle to the surface of said collar, said second portion terminating in an edge for engaging said collar, each said vane being resiliently flexible relative to said collar for flexing inwardly upon movement of the well pipe toward the well bore, and said edge of the second portion sliding relative to said collar upon such flexing, and both of said portions of each said vane extending longitudinally along and at an angle to the length of said collar for circumferentially swirling fluid flowing past said vane.

6. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a collar for mounting on the well pipe, a plurality of vaneson said collar extending into the annular space, each said vane having a portion joined to said collar along a longitudinal line on said collar and extending outwardly and circumferentially at an angle to the surface of said collar, the said angle progressively varying along said longitudinal line such that said portion forms a twisted surface for circumferentially swirling fluid flowing past said vane, and each said vane being resiliently flexible relative to said collar for flexing inwardly upon movement of the well pipe toward the well bore.

7. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a cylindrical collar adapted to be mounted on the well pipe, a plurality of vanes circumferentially spaced around and joined to said collar, each said vane comprising a generally trapezoidal shaped piece of material, a first edge of said trapezoidal shaped piece extending longitudinally along and joined to the surface of said collar, said piece being resiliently flexible along said first edge relative to said collar, said piece extending outwardly with an acute angle formed between said piece and the surface of the collar at said first edge, a flange in said trapezoidal shaped piece along the edge opposite said first edge and said flange extending in a generally circumferential direction, and the portion of said piece between said flange and said first edged formed in a twisted surface extending longitudinally and circumferentially for imparting a circumferential component to the direction of flow of fluid passing said vane to generate turbulence in such fluid.

8. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a cylindrical collar adapted to be mounted on the well pipe, a plurality of vanes circumferentially spaced around and joined to said collar, each said vane comprising a generally trapezoidal shaped piece of metal joined to said collar along an edge, said edge of said trapezoidal shaped piece extending longitudinally along and parallel to the axis of said collar whereby said vane flexes relative to said collar along said edge, said piece extending circumferentially and outwardly with a varying acute angle formed between said piece and the surface of the collar at said first edge for causing flexure of said vane in one direction relative to said collar upon the application of an inward radial force on said vane as by engaging the well bore, and the portion of said piece extending outwardly from said edge formed in a twisted surface extending longitudinally and circumferentially for imparting a circumferential component to the direction of flow of fluid passing said vane to generate turbulence in such fluid.

9. In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the

combination of: a cylindrical collar of relatively thin metal and adapted to be mounted on the well pipe, a

plurality of vanes circumferentially spaced around and joined to said collar, each said vane comprising a generally trapezoidal shaped section of metal joined to said collar along a first edge, said first edge of said trapezoidal shaped section extending longitudinally along said parallel to the axis of said collar whereby flexure of said vane relative to said collar occurs along said first edge, said section extending outwardly and circumferentially with a varying acute angle formed between said section and the surface of the collar at said first edge for causing said section to flex in one direction toward said collar upon being urged inwardly as by engaging the well bore, a flange formed in said trapezoidal shaped section along the edge opposite said first edge and extending in a gen nerally circumferential direction, said flange being relatively parallel to the surface of said collar for engaging the well bore in surface contact, and the portion of said section between said flange and said first edge being trapezoidal shaped and formed in a twisted surface extending longitudinally and circumferentially for imparting a circumferential component to the direction of flow of fluid passing said vane to generate turbulence in such fluid.

10. In a device for gene-rating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a cylindrical collar of relatively thin metal and adapted to be mounted on the well pipe, a plurality of vanes circumferentially spaced around and integrally formed with said collar, each said vane comprising a generally trapezoidal shaped section of the metal of the collar lanced outwardly along three edges of said portion and bent outwardly along the fourth edge, said fourth edge of said trapezoidal shaped section extending longitudinally along and parallel to the axis of said collar, said section extending outwardly with an obtuse angle formed between said section and the surface of the collar at said fourth edge, the magnitude of said angle varying along said fourth edge, a flange formed in said trapezoidal shaped section along the edge opposite said fourth edge and extending in a generally circumferential direction, and the portion of said section between said flange and said fourth edge formed in a twisted surface extending longitudinally and circumferentially for imparting a circumferential component to the direction of flow of fluid passing said vane to generate turbulence in such fluid.

11. In a device for generating fluid turbulence in the annular space between a well pipe and well bore, the combination of: a cylindrical collar of relatively thin metal and adapted to be mounted on the well pipe, a plurality of vanes circumferentially spaced around and mounted on said collar, each said vane comprising a generally trapezoidal shaped section of metal having a base flange joined to said collar, said section being bent along a first edge at said base flange, said first edge extending longitudinally along and parallel to the axis of said collar, said section extending outwardly with a varying acute angle formed between said section and the surface of the collar at said first edge, a flange formed in said trapezoidal shaped section along the edge opposite said first edge and extending inwardly toward said collar at an acute angle to the surface of said collar, the portion of said section between said flange and said first edge being a trapezoidal shape and formed in a twisted surface extending longitudinally and circumferentially for imparting a circumferential component to the direction of flow of fluid passing said vane to generate turbulence in such fluid, the outer extremity of said trapezoidal shaped portion being relatively parallel to the surface of said collar and extending longitudinally and circumferentially, and said flange depending inwardly from said outer extremity and extending longitudinally and circumferentially of said collar.

12. -In a device for generating fluid turbulence in the annular space between a well pipe and a well bore, the combination of: a pair of axially spaced and aligned collars for mounting on the well pipe, a plurality of circumferentially spaced and outwardly bowed staves extending between and mounted on said collars, a third col-l ar aligned with and positioned between said pair of collars, means connecting said third collar to one of said pair of collars, a plurality of vanes on said third collar extending into the annular space, each said vane having a portion joined to said third collar along a longitudinal line on said third collar, said vanes extending outwardly and circumferentially at an angle to the surface of said third collar, the said angle progressively varying along said longitudinal line such that said portion forms a twisted surface for circumferentially swirling fluid flowing past said vane, and each said vane being resiliently 1 l flexible relative to said third collar along the juncture between the vane and collar for flexing inwardly upon movement of the well pipe toward the well bore.

'13. The combination of claim 12 in which the number and circumferential spacing of said staves and said vanes is substantially same with one said vane positioned beneath each said :stave.

14. The combination of claim 12 in which each said vane is positioned between the circumferentially spaced staves for directly contacting the well bore.

References Cited by the Examiner UNITED STATES PATENTS Stolz 166-241 Bettis 166-241 Bettis 166-241 Bettis 166-241 Welles 166241 Kluck 166241 CHARLES E. OCONNELL, Primary Examiner.

Claims

1. IN A DEVICE FOR GENERATING FLUID TUBULENCE IN THE ANNULAR SPACE BETWEEN A WELL PIPE AND A WELL BORE, THE COMBINATION OF: A COLLAR FOR MOUNTING ON THE WELL PIPE, A PLURALITY OF STIFF VANES ON SAID COLLAR EXTENDING OUTWARDLY AT AN ANGLE TO THE SURFACE OF SAID COLLAR AND BEING RESILIENTLY FLEXIBLE RELATIVE TO SAID COLLAR ALONG THE JUNCTURE OF THE VANE WITH THE COLLAR, AND EACH SAID VANE EXTENDING