US2785875A - Jet reamer - Google Patents

Description

C. M. HAYES March 19, 1957 JEI'` REAMER Filed Dec. 20. 1954 FIGB.

FIGJ.

United States Patent JET REAMER Charles M. Hayes, Champaign, Ill.

Application December 20, 1954, Serial No. 476,351

2 Claims. (Cl. Z55-1.8)

This invention relates to a method of and apparatus for drilling wells.

It is frequently desirable in bringing in a well to enlarge the bore of the Well through a selected vertical space. It is also common practice to pack the enlarged cavity with gravel or the like. In wells drilled with a rotary rig, it is presently customary to use what is known as a hydraulic rotary wall scraper in order to enlarge the bore. This consists of hinged blades which fold back into a cylindrical body so as to permit the scrapers being inserted in a bore hole. The blades are so arranged that they may be forced radially outwardly to scrape the wall of the bore hole.

Such a device has a number of marked disadvantages. First, it is a relatively expensive tool both in its initial cost and in its upkeep, since the blades and the body must be kept in repair, and the retracting and extending mechanism is necessarily made accurately and sturdily to ensure proper operation in a bore hole.

Secondly, such a scraper requires a great deal of power to operate. It can, as a practical matter, be used for only a limited enlargement and in only a limitedly large bore hole, because the turning torque increases with the radial reach of the blades.

Thirdly, the shape of the blades is such and the action of the blades in opening is such that in an enlargement of any substantial size, the roof of the enlargement is substantially perpendicular to the aXis of the bore hole.

While for relatively small enlargements, this poses no rgreat problem in gravel packing, in a wide enlargement, the roof of the enlarged chamber does not correspond with the angle of repose of the gravel, so that an unsupported void is left between the root` and the gravel which is introduced into the enlargement.

Fourthly, the scraping action of a conventional hydraulic scraper tends to force mud into porous formations in much the manner in which potatoes are forced into the perforations in a ricer. This is the very antithesis of what is desired, since the object of the enlarging and the scraping is to provide free and unobstructed passage of fluid from porous strata.

In bringing in a well, it is not only desirable to enlarge the bore hole in the producing zone, but it is essential that the enlargement be in the proper zone. It is frequently very difficult to determine where the zone of greatest porosity lies. This is particularly true in drilling through dirty sand and the like where the difference in the drilling rate through zones of diierent porosity is so small as to be practically undetectable.

One of the objects of this invention is to provide a method of accurately and easily determining the location of a producing zone in a well.

Another object is to provide apparatus for enlarging a bore hole, which apparatus is simple, cheap to manufacture, use and maintain, which requires little power to operate, which is capable/ )fgggtensive enlargprent of a bore hole'withoutsubstantial increase in power, which' ice is capable of being used to enlarge a bore hole of large original size, also with no substantial increase in the power required, which is capable of producing an enlarge ment with a roof sloping downwardly at the angle of repose of gravel, or at any desired small or large angle, and which removes mud or other material which would tend to plug a porous formation without squeezing it into the interstices of the formation.

Other objects will become apparent to those skilled in the art in the light of the following disclosure and accompanying drawing.

In accordance with this invention, generally stated, a device is provided which utilizes jets of liquid under pressure to enlarge a bore hole. A method of determining the producing zone or zones of a well is provided which includes the steps of subjecting the wall of the bore of a well to a substantially uniform jetting action and then measuring the enlargement along the wall. By determining where the enlargement is greatest, it is possible to determine accurately the zone of greatest porosity.

In the drawing,

Figure l is a view partly in section showing a device of this invention positioned within a bore hole;

Figure 2 is a view in front elevation partly broken away of a jet reamer constructed in accordance with one embodiment of this invention;

Figure 3 is a bottom plan view of the device shown in Figure 2;

Figure 4 is a sectional view taken along the line 4-4 of Figure 2; and

Figure 5 is a sectional view taken along the line 5-5 of Figure 2.

Referring now to the drawing, reference numeral 1 indicates a jet reamer constructed in accordance with an illustrative Aembodiment of this invention. The jet reamer 1 is connected to a string of pipe 2 through which liquid, generally water, is pumped by means of a pump not here shown.

In Figure l the jet reamer 1, hanging on the string of pipe 2, is shown in the process of enlarging a bore 3 in earth 4 to form a cavity 5. In the cavity 5 shown in Figure 1, there is an enlarged section 6.

In the embodiment shown, the jet reamer 1 includes a hollow cylindrical bomb 10 which is made up in two parts. An upper part 12 of the bomb is provided with a threaded male tool joint connection 14 which takes into a complementary female connection 16 at the lower end of the string of pipe 2. A passage 18 in the connection 14 communicates at its upper end with a passage 20 in the pipe 2 and at its lower end with a cavity 22 in the section 12. The cavity 22 is defined by a heavy wall 24. The inside surface of the wall 24 is cut away at its lower end to deine an annular shoulder 26. The cut away portion of the wall 24 below the shoulder 26 is internally threaded at 28.

A lower part 32 of the bomb 10 is also hollow, an internal cavity 34 being defined by a heavy wall 36. The outside surface of the wall 36 is cut away at its upper end and is externally threaded complementarily to the threaded section 28 of the upper part 12. A spring-biased check valve 40 normally separates the cavity 22 from the cavity 34.

The check valve 40 includes a circular web 42 with a port 44 in its center. The circular web 42 is seated between the upper end of the part 32 and the shoulder 26. A spider 46 on the upper side of the web 42 is provided with a central hole 48 through which a stern 50 of a valve 52 extends. The valve 52 has a head 54 at its lower end which seats on the lower face of the web 42 to close the -port 44. A cap 56, removably secured to the upper end of the stem 50, serves to retain a helical spring 5S. The spring V58, the lower end of which rests against the top of the spider 46 and the upper end of which bears against the underside of the cap 56, biases the head 54 into closed position. Openings 62 between legs 64 of the spider are large enough to permit an unrestricted ow of liquid through the port 44.

In the embodiment of this device shown, the outside surface of the wall 36 is recessed in four places to form two upper ilats 66 and two lower flats 68. The upper flats 66 are diametrically opposite one another. The lower Hats 68 are diametrically opposite one another and perpendicular to the upper flats 66. The wall 36 at the center of each of the flats 66 and 63 is drilled and tapped to take nozzle inserts. Nozzle inserts 70 in the upper ats 66 are provided with an outwardly downwardly directed passage 72. The passage 72 makes an angle of about 35 to 45 from the horizontal, corresponding to the angle of repose of the gravel with which the cavity made by the reamer is to be lled. Nozzle inserts 74 of the flats 68 are provided with axial passages 76. An otherwise closed end 78 of the lower part 32 is also drilled and tapped and provided with a nozzle insert 80, having an axial passage 82.v Eachof the nozzle inserts 70, 74 and 80 in the embodiment shown, is a tool steel cap screw.

In operation, water under pressure is pumped through the pipe string 2, through the passage 18 and into the cavity 22. The pressure of the spring 58 need be only on the order of tive pounds. The pressure of water will be several hundred pounds so that the head 54 will be moved away from the port 44 against the bias of the spring to permit the water to enter the cavity 34 and jet from the nozzles 72, 76 and 82. Since the radially directed nozzle passages 76 are positioned below the downwardly directed passages 72, the uppermost end of a cavity will have a roof which slopes downwardly outwardly at an angle corresponding to the angle at which the passage 72 is set. The vertical distance between the passages 72 and 76 is goverened to some extent by the size of the cavity to be produced. It can be seen that for a given bomb, the larger the cavity, the greater must be the vertical spacing between the passages 72 and 76, to prevent the intersection of the planes of the streams of water from the two sets of nozzles, since beyond the point of intersection, the radially directed stream will be the higher. However, within reasonable limits, a xed spacing will be satisfactory for any enlargement up to the size at which the planes intersect.

The provision of the check valve prevents clogging of the nozzle passages, because the bias of the spring ensures that the valve will close before equilibrium is reached. Thus the water through the nozzles will be under a positive internal pressure until the check valve closes.

When the nozzle inserts take the form of tool steel cap screws, they can easily be replaced. By increasing the pressure of water and substituting nozzle inserts having a passage of smaller diameter, a larger cavity may be made so long as a sucient volume of water is provided to wash out the material in whichl the cavity is made. However, a cavity of large diameter can also be made by increasing the diameter of the bomb and using large nozzle insert passages, since, unlike mechanical wall Scrapers, an increase in diameter of the jet reamer bomb does not appreciably increase its turning torque. Thus, to the limit of the size of the bore above the cavity, the bomb may be made as large as desired. If the bore is to be enlarged all the way to the top, for example, a bomb four feet or more in diameter would not be impractical. It can easily be seen that a blade-type reamer in which the blades extended even tWo feet to either side would impose an unbearable strain on a string of ordinary two inch pipe of any considerable length.

In operation, the jet reamer is self-cleaning, both with respect to its nozzle passages and with respect to the wall of the bore. Even when the wall is caked with drilling mud, the jet reamer of this invention washes it clean, instead of scraping the mud into the interstices of the formation.

In using the jet reamer of this invention with a rotary rig simply to enlarge a bore hole, which may have been made by any means, the connection 14 of the bomb is screwed into the connection 16 at the end of a string of pipe 2. The reamer 1 is then lowered on the end of the pipe to the uppermost point of the section to be enlarged, water is pumped under pressure through the pipe, through the aperture 44 against the bias of the spring 58 and through the passages 72, 76 and 82, and the pipe string and reamer are simultaneously rotated and lowered.

ln dirty sand, using a bomb three inches in diameter on a string of two inch pipe, with quarter inch passages in the nozzle inserts, with the water at a pressure of 30() pounds per square inch, with a bias of tive pounds on the valve head 54, and with the pipe rotated at four to ten revolutions per minute, the jet reamer may be lowered at the rate of one-half a foot per minute to produce a cavity approximately two and one-half feet in diameter, in a bore which was originally four inches in diameter.

In using the jet reamer of this invention to determine the location of a producing zone in a well, the reamer is supplied with water under uniform pressure and is rotated and lowered (or raised) at as uniform a rate in a b'ore hole as ordinary care will permit in the usual rotary r1g.

The reamer is then removed and a bore hole diameter known in the art. The various diameters of the bore hole and their locations are logged. It will be found that'the varying diameter of `the bore hole provides a sensltive measure of the porosity of vthe formation through which the reamer has traveled. The more porous the strata, the greater the diameter of the hole. Since the well should be brought in at the location of the most porous stratum, it is only necessary to note the depth of the greatest enlargement, and to take what steps are necessary to bring in a Well at that level. In bringing in a water well, the porous area is usually further enlarged, and the cavity packed with gravel.

This system is much cheaper and simpler than any method known heretofore, and is at the same time more exact. In actual practice, water wells have been brought in by using this method in marginal areas where other methods have repeatedly failed.

Numerous variations, within the scope of the appended claims, in -the construction of the device of the invention and in the method of determining producing zones will occur to those skilled in the art in the light of the foregoing disclosure. For example, a greater number of passages may be provided in the bomb wall, and the passages may be made to direct jets of liquid in vertically or horizontally overlying bands. The shape, size and location of the passages may be varied. For example, larger or smaller passages may be provided for the downwardly sloping passages than for the radially directed ones, or one or the other kind may be eliminated. The bottom jet may be omitted, although it serves to keep lthe bore clear. The bomb may be made in one piece. The check valve may be put in the pipe line adjacent the bomb. The jet passages may be made in the bomb itself, but in any of these variations some of the advantages `.of the preferred embodiment are lost.

In order to produce a cavity of large diameter at a substantial distance below the mouth of a rela-tively small well hole, various devices for moving the jet nozzles outwardly from the bomb, so as to place them closely adjacent the wall of the hole even as the cavity is enlarged,

will occur to those skilled in the art. For example, high provided with a nozzle insert in its outer end. The droop of` the hoses will permit the bombs being inserted, with the outer ends lof the hoses hanging down, in a relatively small bore hole. As the water pressure within the bomb is increased, the hoses will tend to stand straight out in the direction in which they are secured to the bomb. Thus, by securing hoses at an angle, their nozzles can be directed at the appropriate downward angle even when the hoses are under pressure. Another way to accomplish this expansion is to mount the nozzles on the ends of sections of rigid tubing slideably or telescopically mounted in the walls of the bomb and spring biased to a retracted position. Thus, when pressure is applied, the tube sections will move against the bias of the spring to an extended position at which the nozzles will closely approach thefwall of the cavity. Still another way is to hinge hollow rigid arms to the body of the reamer in such a way that water may be pumped through the arms, hencethrough nozzles at the outer ends of the arms. The erection of the arms can be controlled by a piston l moved by water pressure and serving as a sliding valve to admit water to the arms only when the arms are properly extended. The piston can be spring biased or the weight of the arms may be such as to restore them to their downfolded position against the weight of the piston when the pressure :of water is removed. The term passages as applied to the bomb includes extensible passages of the general character described.

Hav-ing thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A jet reamer for use in enlarging a bore hole in the ground to form a cavity to be packed, comprising a hollow cylindrical bomb having an upper, inverted cupshape part and a lower cup-shape part, said upper and lower parts being threadedly connected and divided internally by a normally closed downwardly opening upwardly spring-biased check valve, said upper part being provided at its upper end with a `threaded connection complementary to a connection on the lower end of a pipe, and said lower part being provided with upper and lower sets of removable nozzle inserts having passages therein, the passages of the upper set of nozzle inserts being directed loutwardly downwardly at an angle no less than the angle of repose of material with which the cavity is to be packed, the passages of the lower set of nozzle inserts being radially directed and spaced a distance below the passages of said upper set of nozzle inserts suicient that the surfaces generated by the projected axes of the passages as the reamer is rotated intersect beyond they desired radius of the enlarged bore hole, all :of said passages communicating with the interior of the bomb.

2. In the art of roducing a well, the method comprising gl,1 ilm1j,n g in the eart a holerdned by a substantially straight side wall, pgpjpgtipg liquid against the said side wall at a substantially uniform pressure along a selected axial section thereof to enlarge the said hole, thereafter measuring the diameter vof the hole along the said section to determine the zone of greatest enlargement, and subsegllgyiullthcuenlagging the zone of greatest snlargggngnt. "m'w'iwm" MW" References Cited in the tile of this patent UNITED STATES PATENTS 671,429 Bacon Apr. 9, 1901 1,732,791 Crowell Oct. 22, 1929 1,848,492 Odenbreit Dec. 17, 1932 2,018,284 Schweitzer et al Oct. 22, 1935 2,327,051 Lyons et al Aug. 17, 1943 2,382,685 Washburn Aug. 14, 1945 2,719,363 Montgomery et al Oct. 4, 1955 OTHER REFERENCES Oil Weekly, August 27, 1945, Caliper Well Logging, pages 32-35.

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