JPS62178688A - Lock bit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an earth boring bit, or rock bit, particularly for discharging a drilling fluid close to the bottom of a borehole. It concerns an improvement of the lock bit which uses an extended nozzle.

In the early prior art rotary lock bits, drilling fluid was discharged into the borehole to cool the lock bit and flush cuttings to the surface. With the advent of high-pressure pumps after World War II, so-called jet pits were developed, improving drilling efficiency by discharging a high-speed flow of drilling fluid directly to the bottom of the borehole.

It is believed that the highest efficiency is achieved by placing the nozzle close to the bottom of the borehole, preferably within a distance of 2 to 6 times the nozzle diameter. The higher the flow rate of the drilling fluid impinging on the bottom of the borehole, the better the cleaning and erosion, and the faster the drilling speed. For this reason, an elongated jet nozzle was developed to replace the nozzle at the lower end of the tube extending from the head of the rock bit close to the bottom of the borehole.

Conventional geometry of cone and extended nozzle tube of commercially successful row relock bits
In this case, the straight lower portion of the elongated nozzle tube is parallel to the axis of the bit due to the space available between the cone of the bit and the wall of the borehole. Thus, the various configurations used for extended jet nozzles in commercially successful bits include:
The discharge direction of the nozzle is parallel to the axis of the bit and substantially perpendicular to the bottom of the borehole.

In a three-cone type rock bit, there are usually three mutually oriented elongated nozzles and one central jet nozzle. The function of the central jet nozzle, which extends from the head of the bit to a distance from the bottom of the borehole, is to clean the cone and move cuttings from the central area to areas outside the central area.
This causes the cuttings to be captured in the rising return flow. A disadvantage of such a construction is that all three elongated jet nozzles impinge the drilling fluid approximately perpendicularly to the bottom of the borehole at the same radial location, which reduces the energy of the multiple jets of drilling fluid. is concentrated in a relatively small annular portion of the total area of the bottom of the borehole. It has been proposed in the past to discharge drilling fluid in a sweeping action across the bottom of the borehole, but none of these have met with great commercial success.

SUMMARY OF THE INVENTION It is an object of the present invention to improve a roke relock bit with an elongated jet nozzle to improve drilling efficiency and thereby increase drilling speed.

Such an object of the present invention is to (1) provide a high-velocity sweeping action of drilling fluid against the bottom surface of the borehole, or (2) increase the portion of the bottom surface of the borehole that is directly impinged by a high-energy jet of drilling fluid. This is accomplished by providing a cone-shaped rock bit with a nozzle or jet tube and a set of nozzles. Each nozzle tube is (
1) an inlet connected to the head at a location above and between adjacent cutters of each set; and (2) a straight inlet located at a height near the lower end of the cone or cutter and the bottom of the borehole. and an exit area. At least one of the nozzle tubes is provided with a wear-resistant oriented or deflected nozzle at the lower end of the straight region, the nozzle having a centerline of the flow of the drilling fluid centered at the center of the straight region of the tube. The line and bit deviate from the axis of rotation,
The deflection is preferably in the range 10 to 30" to effectively direct the drilling fluid exiting the nozzle. The location at which the jet of drilling fluid impinges on the bottom of the borehole is spaced an equal distance from the bottom of the borehole. It is not determined solely by the structure of the cutter and the extended nozzle tube.Orienting the nozzle in a particular direction can (1) provide an improved sweeping action of the jet against the bottom of the borehole; or (2) ) The nozzle may be oriented in any desired direction within the elongated nozzle tube to increase the portion of the bottom surface of the borehole that is directly impinged by the high-energy jet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the accompanying drawings, reference numeral 11 designates a locking bit with a head 13 configured to be connected at a threaded portion 15 to a drill string member, not shown in the drawings.

The head 13 includes a plurality of welded head sections;
A plurality of elongated nozzles or jet tubes 17
It is becoming more and more. Each head section has a cantilevered bearing shaft (not shown) supporting a rotatable cutter 19, which has a scraping tooth 21 that engages the bottom of the borehole during drilling. It's evening.

A typical lock bit has a sealing device (not shown) and a lubricating device located between each cutter and the bearing shaft, the outer surface 23 of the lubricating device being shown in FIG.
only appears. The sealing device and the lubricating device cooperate with each other to maintain lubricating fluid between each bearing shaft and the inner surface of the corresponding cutter.

In FIG. 2, the head 13 has a cavity (not shown) communicating with a fluid passageway 25, which extends downwardly through the elongated jet tube 17a. The curved part 27 and the straight part, that is, the vertical part 2
9.

A tapered jet nozzle 31 for wear resistance is provided at the lower end of the tube 17a, thus the straight portion 29 thereof. Jet nozzle 31 is a symmetrical or undirected nozzle that does not deflect the flow of drilling fluid away from the longitudinal axis of the tube immediately above the nozzle. The nozzle 31 is retained by a resilient snap ring 33 that engages matching grooves in the nozzle and tube, and is sealed within the tube by an O-ring 32 placed in the appropriate groove. . Thus nozzle 3
1 flows substantially parallel to the longitudinal axis of the bit and to the two straight sections of tube 17a. Furthermore, the lower end 35 of the nozzle 31 has teeth 21, shown in phantom in FIGS. preferably within a distance of 2 to 6 times the diameter of the nozzle from the impingement area of the drilling fluid on the bottom surface 37 of the borehole formed by the cooperative action of all the teeth by rotating with the corresponding cutter. .

Another jet tube 17b is shown in FIG. 3 having an asymmetrical or oriented nozzle 39 retained within the tube by a snap ring 41 and sealed by an O-ring 42. . When the lower end 43 of the nozzle 39 is also M1 along the center of the flow of the drilling fluid, the diameter of the nozzle is 2 mm from the bottom surface 37 of the borehole.
It is preferable to be located within a range of ~6 times the distance.

In this case, the flow of drilling fluid 45 is deflected from the centerline of the bit or the centerline of the straight section of the tube at a preferred angle of 10 to 30 DEG.

A third nozzle, jet tube 17c, is shown in FIG. 4 and is retained by a snap ring 49 and sealed by an O-ring 48, and is preferably configured to direct the drilling fluid at an angle of 10-30''. The tube is substantially identical to the tube shown in FIG. In the case of this tube as well, the lower end 53 of the nozzle is located at a distance of about 2 to 6 nozzle diameters from the bottom of the borehole as viewed along the centerline of the drilling fluid flow 51.

As is clear from FIG. 6, each oriented nozzle 39 and 47 is a tapered oriented nozzle whose internal passage ideally deflects the fluid flowing through it away from the centerline of the straight region of the tube. It is an asymmetrical nozzle so that it is asymmetrical. The upper surface 73, which has a spherical radius R1, intersects a cylinder with a diameter called the nozzle diameter or throat diameter. The cylindrical surface 75 appearing in the cross section of FIG. 6 forms a tangent to the radius R2, and is smoothly connected to the spherical upper surface 73. Further, the cylindrical surface 75 is tangential to the radius R3, which is tangential to the spherical radius R1. The nozzle nozzle is provided with a conventional chamfer 76. Snap ring groove 7
7 is provided, and the extraction groove has a notch 79 on one side, so that when inserting or removing the nozzle, pliers (not shown in the figure) can be inserted to operate the snap ring. It is now possible to do so.

As shown in FIG. 5, a central jet nozzle 83 is disposed in the center of the head 13 to direct a portion of the drilling fluid past the cutter and along the centerline of the bit toward the bottom of the borehole. ing.

A sleeve 85 with a shoulder 87 for receiving a wear-resistant nozzle insert 91 is welded to the head 13 at a location indicated by 8, the insert 91 being attached to the shoulder 87 of the sleeve 85. It is in contact with 93. 0
A ring 95 is compressed against the outer surface 97 of the nozzle insert 91 and the opposing surface of the groove. A threaded hollow retainer 101 engages threads 103 in the sleeve 85 and thereby holds the nozzle insert 91. Although not particularly relevant to the present invention, each leg constituting the head has a lubricating device 107 therein, as partially shown in FIG.

Orientation of the nozzle is maintained using a suitable adhesive or using any of several possible mechanical fixing devices (not shown).

In operation, drilling fluid is pumped through the drill string and lock bit 11, and the drill string and lock bit are rotated so that the teeth 21 of the cutter 19 break up soil and force the cuttings to the surface. Ru. The drilling fluid flowing through the preferred embodiment is divided into four streams.

Three of the streams exit via the nozzles 31, 39, 47 and the other one via the central jet nozzle 83. The orientation of one or more of the elongated nozzles 31, 47 in which the nozzles are arranged ensures that the three jets of drilling fluid exiting the three nozzles are aligned with the axis of the elongated tube and It is possible to impinge on the bottom of the borehole in a region different from the region immediately below the jet nozzle, which extends parallel to the axis of the bit.

The ability to orient the different nozzles in different directions makes it possible to use a sweeping action that provides more efficient cleaning and more efficient erosion of one bottom surface of the borehole, thereby increasing the drilling speed. . The highest efficiency is achieved when the lower end of each nozzle is spaced from the bottom of the borehole by a distance substantially equal to two to six times the diameter of the nozzle throat.

In the following, the present invention has been described in detail with reference to specific embodiments, but the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art that

[Brief explanation of drawings]

FIG. 1 is a perspective view of a three-cone rock bit with an elongated jet nozzle constructed in accordance with the present invention. FIG. 2 is a longitudinal cross-sectional view of one elongated jet tube and sintered tungsten carbide nozzle of conventional undirected construction configured to impinge drilling fluid perpendicularly to the bottom of the borehole. be. Figures 3 and 4 show an asymmetrical nozzle for ejecting drilling fluid from a corresponding tube at a predetermined inclined angular range; It is a diagram. FIG. 5 is a partial longitudinal sectional view of the central jet nozzle and the corresponding head and part of the lubricating device. FIG. 6 is an enlarged partial longitudinal cross-sectional view of the oriented nozzle used in the jet tube shown in FIGS. 3 and 4. FIG. 11...Rock bit, 13...Head, 15...
- Threaded portion, 17... Extended nozzle (jet tube), 19... Cutter, 21... Teeth, 23...
Outer surface, 25...Fluid passage, 29...Straight portion, 31.
...Jet nozzle, 32...0 ring, 33...
snap ring. 34... Flow of drilling fluid, 35... Lower end, 37...
・Bottom of the borehole, 39... Nozzle with direction, 41
...Snap ring, 42...0 ring, 43...
- Lower end, 45... Flow of drilling fluid, 47... Asymmetrical nozzle. 48...0 ring, 49...snap ring 551
... Flow of drilling fluid, 53 ... Lower end, 73 ... Upper surface, 75 ... Cylindrical surface, 76 ... Chamfered portion, 77 ...
- Notch, 79... Notch, 83... Central jet nozzle, 85... Sleeve, 87... Shoulder, 91...
...Nozzle insert. 93...Shoulder part, 95...0 ring, 97...Outer surface, 99...Groove surface, 101...Retainer, 103...
...Screw, 107...Lubricating device patent applicant Hughes Tool Company Knee Varnish Knee

Claims (3)

[Claims] (1) A type having a plurality of rotatable cutters carried on a cantilevered bearing shaft extending from a head, and a nozzle for directing drilling fluid from a cavity in the head toward the bottom of the borehole. An improved lock bit includes a plurality of radially spaced nozzle tubes each having an inlet region connected to the head and a substantially straight outlet region, and a throat of a predetermined diameter. an end of the cutter located in the exit region of one or more of the tubes within a distance of substantially 2 to 6 times the diameter of the throat from the bottom of the borehole; a directional nozzle having a lower end disposed proximate to a directional nozzle, each directional nozzle directing an outlet flow that is inclined relative to the centerline of the lock bit and a straight section of the passageway to impinge on the bottom surface of the borehole in a sweeping action. forming an asymmetrical passageway, wherein at least one of the high velocity flow of drilling fluid flows through the tube to enhance cutting removal during drilling and erosion of the bottom surface of the borehole. An improved lock bit configured to impinge on the bottom surface of the borehole in an area other than an area below the nozzle tube parallel to the extension of the lock bit and the axis of the lock bit. (2) An improved type of rotatable cutter having a plurality of rotatable cutters carried on a cantilevered bearing shaft extending from the head and a nozzle directing the drilling fluid from the head toward the bottom of the borehole. a locking bit, each having a curved inlet area connected to said head;
three radially spaced nozzle tubes having a substantially straight exit region terminating at a height near the tip of the cutter and located near the bottom of the borehole during drilling; a throat provided in the exit region of each of two of the three tubes, the diameter of the throat being substantially 2 mm below the bottom surface of the borehole;
a tapered directing nozzle having a lower end disposed proximate the end of the cutter within a distance of ~6 times; each directing nozzle being in a straight region of the centerline and passageway of the locking bit; an asymmetrical passage forming an outlet flow inclined at various angles to the borehole; having a lower end disposed proximate the end of the cutter within a distance of substantially 2 to 6 times the diameter of the lock bit, and having an exit flow substantially parallel to the centerline of the lock bit. a non-directed tapered symmetrical nozzle configured to form a symmetrical undirected nozzle, each of the three nozzles configured to form a symmetrical non-directed nozzle in a sweeping action to improve cutting evacuation and erosion of the bottom surface of the borehole. An improved lock bit configured to direct drilling fluid to different areas of the bottom of a borehole. (3) An improved type of rotatable cutter having a plurality of rotatable cutters carried on a cantilevered bearing shaft extending from the head and a nozzle directing the drilling fluid from the head towards the bottom of the borehole. in a rock bit, a central jet disposed substantially centrally in the head and configured to direct drilling fluid past the cutter and along a centerline of the rock bit toward the bottom of the borehole during drilling; three nozzles each having a curved inlet region connected to said head and a substantially straight outlet region terminating at a height near the tip of said cutter and located near the bottom of the borehole during drilling; radially spaced nozzle tubes, each having a throat of a predetermined diameter, provided in the outlet region of each of two of the three tubes, the throat being further away from the bottom of the borehole; substantially 2 of the diameter of
a tapered directing nozzle having a lower end disposed proximate the end of the cutter within a distance of ~6 times; each directing nozzle being in a straight region of the centerline and passageway of the locking bit; an asymmetrical passage forming an outlet flow inclined at various angles to the borehole; having a lower end disposed proximate the end of the cutter within a distance of substantially 2 to 6 times the diameter of the lock bit, and having an exit flow substantially parallel to the centerline of the lock bit. a non-directed tapered symmetrical nozzle configured to form a symmetrical undirected nozzle, each of the three nozzles configured to form a symmetrical non-directed nozzle in a sweeping action to improve cutting evacuation and erosion of the bottom surface of the borehole. An improved lock bit configured to direct drilling fluid to different areas of the bottom of a borehole.