EP0296208B1 - Inclined jet drilling tool - Google Patents

Abstract

A tool for drilling has a diameter D, teeth having a height H and carried by wheels, irrigation means adapted to deliver at least one irrigation fluid jet through a calibrated orifice, the centre of said jet at the outlet of the orifice being situated at a distance d from a plane perpendicular to the axis of the tool passing through the apex of the teeth viewed from the working face. According to the present invention, the magnitudes D, H and d are such that d 1.8 H and 0.125 D < d < 0.185 D. Application to drilling into grounds.

Description

The present invention relates to a drilling tool. More particularly, but without being limiting, the present invention relates to a drilling tool or drill bit which can be fixed to the lower end of a drilling column. The tool according to the invention is of a type comprising several rotating members provided with cutting elements, these members being able to be conical knobs rotating around bearings whose axes are inclined relative to the central axis of the tool.

In the past, the performance of such tools, used for drilling land, has been improved by the simultaneous action of jets of drilling fluid which strike the bottom of the hole, or cutting face, in each of the free spaces between the attacking bodies. At the level of the tool, this drilling fluid must have as essential functions to cool the tool, to clean this tool as well as the working face, and to quickly evacuate the cuttings towards the annular space included between the drill string and the wall of the drilled hole.

In a first type of tool according to the prior art, the fluid jets open out at a place located notably above the level of the rollers. As a result, before reaching the cutting face, the jets pass through the drilling fluid loaded with cuttings which fills the bottom of the drilled hole. As a result, the flow velocity of the jets at waistline level is significantly slowed down, reducing their effectiveness. In addition, the jets entrain part of the drilling fluid loaded with cuttings towards the cutting face where the cuttings are reground by the tool, the yield of which is thus reduced. In addition, the fluid jets create an overpressure on the cutting face which compresses the ground and it can be seen that the contact zone between the tool and the cutting face where the cuttings are produced is not sufficiently irrigated by the drilling fluid.

Various modifications have been proposed, in particular the tools of the type indicated above have been modified so that the jets of drilling fluid emerge as close as possible to the working face and, sometimes even, an axial jet has been added. However, these improvements were not entirely satisfactory: the regrinding of the cuttings could not be eliminated, any more than the overpressure at the level of the cutting face.

In a second type of tool according to the prior art, it has been proposed to use, in combination with the irrigation means constituted by jets of fluid, means for suctioning the fluid loaded with cuttings, these means comprising a jet directed in the opposite direction to that of tool progression.

Such tools are described in particular in French patents 2,378,938, 2,421,270 and 2,421,271.

The present invention provides a tool of the first type defined above, which, by its design, is simple and robust, while having considerably improved operating performance compared to tools of the same type and which approximate those of the second type, while they do not include suction jets.

• . un corps d'outil destiné à être entraîné en rotation par un porte-outil, une cavité étant ménagée dans ce corps pour recevoir à travers le porte-outil un fluide sous pression,
• . une pluralité d'organes tournants portés par le corps de l'outil et munis de dents d'attaque des terrains sur un front de taille, ces dents ayant une hauteur H, le diamètre dudit outil étant D,
• . des moyens d'irrigation adaptés à délivrer au moins un jet fluide d'irrigation dirigé vers le front de taille, ces moyens comportant au moins un premier orifice calibré implanté sur le corps de l'outil, communiquant avec la cavité du corps d'outils et débouchant dans un espace compris entre deux organes tournants adjacents, ledit orifice calibré étant adapté à produire un jet fluide dirigé vers l'un des deux organes tournants entre lesquels est défini ledit premier espace, le centre dudit jet à sa sortie dudit orifice étant situé à une distance d du plan P perpendiculaire à l'axe de l'outil passant par le sommet des dents considérées du côté du front de taille. Selon la présente invention les grandeurs D, H et d sont telles que

$$\text{d ≧ 1,8 H et}$$

$$\text{0,125 D < d < 0,185 D}$$

The tool for drilling land comprises, according to the present invention:

• . a tool body intended to be driven in rotation by a tool holder, a cavity being formed in this body to receive a pressurized fluid through the tool holder,
• . a plurality of rotating members carried by the body of the tool and provided with ground attack teeth on a face, these teeth having a height H, the diameter of said tool being D,
• . irrigation means adapted to deliver at least one fluid irrigation jet directed towards the cutting face, these means comprising at least one first calibrated orifice implanted on the body of the tool, communicating with the cavity of the tool body and opening into a space between two adjacent rotating members, said calibrated orifice being adapted to produce a fluid jet directed towards one of the two rotating members between which said first space is defined, the center of said jet at its outlet from said orifice being located at a distance d from the plane P perpendicular to the axis of the tool passing through the top of the teeth considered on the side of the cutting face. According to the present invention, the magnitudes D, H and d are such that

$$\text{d ≧ 1.8 H and}$$

$$\text{0.125 D <d <0.185 D}$$

The tool according to the invention comprises three rotating members defining three spaces comprised between two adjacent rotating members, and for which only two of the spaces are equipped with calibrated orifices, only one of these spaces being free of any fluid injection orifice. .

$$\text{0,1 D < t < 0,15 D}$$

When the tool according to the invention comprises irrigation means which comprise an extension carrying the calibrated orifice, the extension being at a minimum distance t from the plane P, then the magnitudes D, H and t can be such that: $$\text{t ≧ 1.5 H and}$$

$$\text{0.1 D <t <0.15 D}$$

The irrigation means may include at least two calibrated orifices adapted to produce fluid jets respectively directed towards the two rotating members between which the first space is defined.

The irrigation means may include at least one irrigation nozzle or nozzle having the calibrated orifice (s).

The jet of fluid produced by the orifice may have an orientation substantially tangential to the exterior surface of the rotating members.

The rotating members may have a substantially conical shape, and the orifice may be constituted by slots whose direction of elongation may be substantially parallel to a generator of a rotating member.

The axis of the jet produced by the orifice, when the latter is supported by a nozzle, may make an angle between 15 ° and 45 ° with the plane P and preferably an angle equal to 30 °.

When the injection orifice has a slit shape, two of the walls defining the internal shape of this slit may belong to two planes making an angle of 15 ° between them.

According to a variant, the tool may include two calibrated orifices located on either side of a plane substantially parallel to the axis of the tool, containing substantially the axis of rotation of a member. turning. These orifices can be adapted to each produce a jet oriented towards the rotating member and directed towards the cutting face. In addition, these orifices can be adapted to produce jets offset from one another.

The tool may include two other calibrated orifices each of said orifices being adapted to produce a jet directed towards the cutting face and towards one of said other rotating members respectively.

Each of the jets produced by the other orifices can be oriented substantially at 60 ° relative to the median axis defined by the two rotating members closest to said orifice.

One of the offset jets can make an angle close to 30 ° relative to the median axis defined by the two rotating members closest to this orifice.

où D correspond au diamètre de l'outil comme cela à déjà et e correspond à la distance séparant ledit orifice de la circonférence circonscrite à l'outil.The other offset jet can make an angle close to theta, theta being defined by: $$\text{tg (theta) =}\frac{\sqrt{\text{3}}}{\text{1-}\frac{\text{4th}}{\text{D}}}$$

where D corresponds to the diameter of the tool like that already and e corresponds to the distance separating said orifice from the circumference circumscribed with the tool.

The tool according to the present invention is particularly well suited for drilling soft and sticky terrains.

• la figure 1 représente, vu de dessous, l'outil selon l'invention;
• la figure 2 illustre schématiquement les grandeurs ayant une importance pour l'obtention de bonnes performances de l'outil;
• les figures 3 et 4 montrent l'outil vu en coupe, respectivement selon les lignes X′X et Y′Y de la figure 1,
• la figure 5 illustre schématiquement la configuration d'un orifice calibré avec son conduit amont,
• la figure 6 représente un mode de réalisation particulièrement efficace pour l'enlèvement des déblais, et
• les figures 7 à 11 montrent les différentes variantes de réalisation et de fixation des duses;

The invention can be well understood and all of its advantages will become clear on reading the description which follows, illustrated by the appended figures in which:

• Figure 1 shows, seen from below, the tool according to the invention;
• FIG. 2 schematically illustrates the quantities having an importance for obtaining good performance of the tool;
• FIGS. 3 and 4 show the tool seen in section, respectively along the lines X′X and Y′Y of FIG. 1,
• FIG. 5 schematically illustrates the configuration of a calibrated orifice with its upstream duct,
• FIG. 6 represents an embodiment which is particularly effective for removing the cuttings, and
• Figures 7 to 11 show the different embodiments and fixing of the nozzles;

The tool represented in the figures is composed of a body 1 provided with three arms 2, only two of which are represented in FIGS. 2 and 3. These arms carry bodies for attacking the terrains constituted, for example, by rollers or conical knobs 3, 4 and 5 rotating on bearings not shown and whose axes are inclined relative to the axis 6 of the tool which corresponds to the direction of advance of the tool. Each of these rotating members, which can be of any known type, has teeth, as shown in Figures 1 and 2, capable of attacking the terrain at the level of the cutting face. The height H, Figure 2, designates the height of the teeth.

The upper part 7 of the body 1 (fig. 3 and 4) is threaded to ensure the connection of the tool to a tool-carrying element which drives it in rotation.

This tool holder, designated by the reference 8 (cf. FIG. 4), can be constituted by the drilling column in the case of rotary drilling. When the tool is directly driven in rotation by a downhole motor, the tool holder will be constituted by the rotor of this motor.

In the body 1 of the tool is formed a cavity 9 which communicates directly with the inner pipe of the drill string.

The body of the tool is provided with nozzles 10a and 11a having calibrated orifices (10b, 10c, 11b and 11c) which communicate with the cavity 9 through the passages 15 and 16. The nozzles 10a and 11a are placed in two free spaces 10 and 11 between the rollers, preferably being located substantially in the bisector planes of these spaces. The pairs of orifices (10b, 10c; 11b, 11c) are placed so that, during the operation of the tool, the fluid which feeds the cavity 9 escapes through these orifices (10b, 10c; 11b, 11c ) by forming two pairs of irrigation jets which flow in two free spaces 10 and 11 included respectively between the rotary members 4 and 5, 3 and 5 and in a direction having a component directed in the direction of progression of the tool in operation.

The reference 12 designates the third free space between the rotary members 3 and 4 which is free of any injection orifice (cf. Figures 1 and 4).

This provides an area for clearing the mud loaded with cuttings which is quickly removed from the face.

The cuttings are thus removed from the working face as soon as they are formed and, under these conditions, the drilling tool remains clean at all times, which allows increased drilling speeds and increases the longevity of the tool members ( teeth, bearings, etc ...). This is symbolized by the arrows 17.

As shown in Figure 3, It may be advantageous that the supply of fluid to the calibrated orifices (10b, 10c; 11b, 11c), from the cavity 9 is through conduits designed so as to reduce the most possible pressure losses of the fluid in particular by a tangential connection to the wall of the cavity 9.

In the embodiment illustrated in the figures, the calibrated orifices (10b, 10c; 11b, 11c) are constituted by the orifices of the nozzles 10a and 11a respectively.

The different orifices can be oriented so that the jets of fluid which exit from these orifices reach the rotating members in the immediate vicinity of the cutting face. In other words, the axes of the jets leaving the calibrated orifices can be substantially tangent to the rotating members.

These calibrated orifices can be circular orifices, but preferably they will have a slit shape, as can be seen in FIG. 2.

Under these conditions, to obtain maximum efficiency of the irrigation jets, each of these slots is substantially parallel to the generator of the rotating member reached by the fluid jet, and arranged so that the jet acts over the greatest length. possible from this generator.

ou/et

Excellent results can be obtained if the following conditions are met:

or and

d :

distance qui sépare le centre 18 d'un orifice de sortie 10b du plan P perpendiculaire à l'axe de l'outil 6 et qui passe par le sommet 19 des dents les plus proches du front de taille;

H :

représente la hauteur des dents 20;

D :

représente le diamètre de l'outil. Sur la figure 2, on a représenté D/2 qui correspond au rayon de l'outil, et

t :

la distance minimum entre la base de la buse ou du prolongateur et le plan P.

The different letters in the above equations correspond to the definitions below which are illustrated in Figure 2.

d:

distance which separates the center 18 of an outlet orifice 10b from the plane P perpendicular to the axis of the tool 6 and which passes through the apex 19 of the teeth closest to the cutting face;

H:

represents the height of the teeth 20;

D:

represents the diameter of the tool. In FIG. 2, D / 2 is shown which corresponds to the radius of the tool, and

t:

the minimum distance between the base of the nozzle or extension and the plane P.

FIG. 5 represents the section of a calibrated orifice 10b. This orifice is connected to a conduit 21 having a central axis 22 opening at 18 at the level of the orifice 10.

The orifices 10b, 10c, 11b and 11c can have a slit shape, as shown in FIG. 2.

The planes 23 and 24 defining the walls of the duct 21 may make between them a low angle alpha (in Greek letter in FIG. 5), for example substantially close to 15 °.

The beta angle (in Greek letter in FIG. 5) formed by the axis 22 of the conduit 10b, this axis corresponding substantially to the axis of the jet, with the plane P may advantageously be between 15 ° and 45 ° and preferably equal to 30 °.

When a nozzle has two calibrated orifices, the central axes of these orifices can advantageously form an angle of 120 ° between them.

Of course, the nozzles are fixed interchangeably and they will be chosen by the user according to the flow rate and the pressure of the irrigation fluid.

Modifications may be made without departing from the scope of the present invention. For example, as shown in FIG. 3, the irrigation nozzles such as 10a could be carried by an extension 13 fixed to the body of the tool by any known means, such as a keying or a thread 14. This extension could be an integral part of the tool body.

Figure 6 shows an embodiment of the tool particularly favorable for the removal of cuttings. This figure corresponds to a view from above of the face.

The arrow 25 corresponds to the direction of rotation of the tool.

This embodiment is described on the basis of a tool comprising three rotating members which are cones 26, 27 and 28.

The axes of rotation of the cones on themselves are designated respectively by the references 29, 30 and 31.

References 32 and 33 designate two nozzles each having two oblong orifices, respectively 32b, 32c and 33b, 33c, placed on either side of the cone 26.

The jets 34, 35, 36 and 37 produced by the calibrated orifices 32b, 32c, 33b and 33c may be inclined at 60 ° (average value with respect to the axis of the tube supplying the fluid extender, which is parallel to tool axis). This corresponds to the gamma angle in Figure 5.

Preferably each jet can be tangent to the cone it sprinkles, in contact with the tool and the rock.

In the embodiment of FIG. 6, the orientation of the jets in a plane normal to the axis of the tool at the level of the cutting face is as follows: each nozzle 32, 33 has 2 orifices including one 32b, and 33b respectively, is oriented at approximately 60 ° with respect to the median axis 38, and 39 respectively, of the two cones 26, 28, and 26, 27 respectively, towards the inter-cone space 40 having no nozzles (space between cones 27 and 28 in Figure 6).

With regard to the other orifices 32c and 33c of each nozzle 32 and 33 respectively, for that 32c located between the cones between the cones 26 and 28, the orientation of the jet is about 30 °, so as to clean the teeth of the taper 26 located near the center of the tool. The angle of 30 ° is to be considered with respect to the median axis 38 of the cones 26 and 28.

de manière à nettoyer efficacement le diamètre extérieur du trou en cours de forage, ainsi que les dents ou lames, ou picots extrêmes du cône 1, e correspond à la distance qui sépare le centre de l'orifice calibré 33c de la circonférence de l'outil.For the orifice 33c located between the cones 26 and 27, the orientation of the jet is carried out according to a angle Theta defined by: $$\text{tg (Theta) =}\frac{\sqrt{\text{3}}}{\text{1 -}\frac{\text{4th}}{\text{D}}}$$

so as to effectively clean the outside diameter of the hole being drilled, as well as the teeth or blades, or extreme pins of the cone 1, e corresponds to the distance which separates the center of the calibrated orifice 33c from the circumference of the tool.

D is the diameter of the tool, as already indicated.

The angle Theta is to be considered with respect to the median axis 39 of the cones 26 and 27.

If the space 40 between the cones 27 and 28 (according to FIG. 1) has a nozzle, this will be blocked, or the location will be hollowed out and organized so as to favor a good return of the cuttings towards the ring finger.

The tool can be fitted with a central nozzle for good cleaning of the dome and the center of the tool.

The nozzles 47 (Figure 7) can be made of carbide. They can be placed inside the extension tubes 42, in order to provide protection against impacts.

The internal shape 43 is in the lower part, conical or paraboloid of revolution, so as to ensure perfect continuity of the flow between the tube and the nozzle.

FIG. 8 represents an embodiment of the nozzle 32 and FIG. 9 of the nozzle 33. In this embodiment the angle Theta is 72 °. Reference 44 designates a fixing mark.

The fixing of the nozzles in the extension tubes can be done either by brazing (non recoverable tubes), or mechanically (removable tubes).

FIG. 10 represents a removable nozzle 45. The sealing of this nozzle to the extension tube is ensured by a seal 46 "0 RING".

Two keys 47 and 48 (fig. 11) allow the nozzle to be fixed in the transerval position along the median axis. A locking screw 49 with stud can provide positioning security and avoids any vibration phenomenon.

This screw with nipple rests on a washer 50 in neoprene (or any other elastomer) in order to ensure the brake, unscrewing and creep functions of the elastomer after tightening, generates a setting of the nipple in the housing in the nozzle .

Claims (13)

1. A drilling tool comprising :

- a tool body (1) intended to be rotated by a tool-holder (8), in which a cavity (9) is formed in the body (1) for receiving a pressurised fluid through the tool-holder (8),

- a plurality of rotary members (3, 4, 5) carried by the tool body (1) and fitted with teeth for cutting ground at a cutting face, these teeth being of a height H, the diameter, of the tool being D,

- an irrigation means (10a, 11a) adapted-to produce at least one irrigation fluid jet directed to the cutting face, these means (10a, 11a) comprising at least one first calibrated orifice (10b, 10c, 11b, 11c) inside the tool body communicating with the cavity (9) of the tool body (1) and having an outlet into a space (10, 11) formed between two adjacent rotary members (4, 5; 5, 3), the calibrated orifice (10b, 10c, 11b, 11c) being adapted to produce a fluid jet directed to one of the two rotary members (4, 5; 5, 3) between which is formed the above-mentioned first space (10, 11), the centre of the jet at its outlet from the orifice (10b, 10c, 11b, 11c) being located at a'distance d from the plane perpendicular to the axis (6) of the tool passing through the apex of the teeth as seen from the cutting face side, the tool comprising three rotary members (3, 4, 5) delineating three spaces (10, 11, 12) formed between two adjacent rotary members (4, 5; 5, 3; 3, 4) characterised in that only two of these spaces (10, 11) have calibrated orifices (10b, 10c, 11b, 11c), only one space has no injection orifice and the measurements D, H and d are such that

$$\text{d ≧ 1.8 H and}$$

$$\text{0.125 D < d < 0.185 D}$$

2. Tool in accordance with claim 1, in which the irrigation means (10a, 11a) have an extension carrying the calibrated orifice (10b, 10c, 11b, 11c), the extension being at' a minimum distance of t from the plane, characterised in that the measurements D, H and t are such that : $$\text{t ≧ 1.5H and}$$

$$\text{0.1 D < t < 0.15 D}$$

3. Tool in accordance with one of claims 1 or 2, characterised in that the irrigation means comprise at least two calibrated orifices (10c, 10b; 11b, 11c) adapted so as to produce fluid jets directed respectively towards the two rotary members (4, 5; 5, 3) between which the first space (10; 11) is formed.

4. Tool in accordance with one of claims 1 to 3 in which the irrigation means comprises at least one irrigation nozzle (10a; 10b) feeding the calibrated orifice or orifices (10b, 10c; 11b, 11c).

5. Tool in accordance with one of the above claims, characterised in that the fluid jet produced by the orifice (10b; 10c; 11b; 11c) has an orientation substantially at a tangent to the exterior surface of the rotary members (4; 5; 5; 3).

6. Tool in accordance with one of the preceding claims, in which the rotary members are substantially of conical shape, characterised in that the orifice is formed by slits substantially parallel to a generatrix of a rotary member.

7. Tool in accordance with one of the preceding claims, in which the orifice is fed by a nozzle, characterised in that the axis of the jet produced by the orifice forms an angle of between 15° and 45° with the plane and by preference an angle equal to 30°.

8. Tool in accordance with claim 7, characterised in that the orifice has the form of a slit, in which two of the walls delineating the internal form of the slit belong to two planes forming between them an angle of substantially 15°.

9. Tool in accordance with one of the preceding claims, characterised in that it has two calibrated orifices located on either side of a plane substantially parallel to the axis of the tool containing substantially the axis of rotation of a rotary member, characterised in that the orifices are adapted in such a way that each produces a jet oriented towards the rotating member and directed towards the cutting face and in that the orifices are adapted to produce jets that are offset in relation to each other.

10. Tool in accordance with claim 9 comprising two other rotary members, characterised in that it comprises two other calibrated orifices, each of the orifices being adapted to produce a jet directed towards the cutting face and towards one of the other rotary members respectively.

11. Tool in accordance with claim 10, characterised in that each of the jets produced by the other orifices is oriented substantially at an angle of 60° in relation to the plane defined by the two rotary organs closest to the orifice.

12. Tool in accordance with one of claims 9 to 11, characterised in that one of the offset jets forms an angle close to 30° in relation to the plane defined by the two rotary members closest to the orifice.

13. Tool in accordance with claim 12, characterised in that the other offset jet forms an angle close to theta, theta being defined by : $$\text{tg (Theta) =}\frac{\sqrt{\text{3}}}{\text{1 -}\frac{\text{4e}}{\text{D}}}$$

where D corresponds to the diameter of the tool and e corresponds to the distance separating the orifice from the distance of the hole.

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