DE1904913A1 - Elbow part for directional drill rods - Google Patents

Description

ΪΑΤΒ N τα: "WALT DIPL. ΙΪΤΟ. E. I. RO Λ OGS: ϊϋί'.Ο »ΗΟΧΙΡΡΙΝΒ-ΛνΕΧ, ΕΕη- STIUlSSK ΐ, χνοκ. MfMS

R. 732

Augsburg, January 30, 1969

Rolls-Royce Limited, Moor Lane, Derby, England

Elbow part for directional drill rods

The invention relates to elbow parts for directional drill rods which are provided with an inclined end face which determines the directional angle.

In directional drilling, it is important to use the directional section of the drill pipe in the azimuth direction To keep reference to a drill head, which is driven by a drive motor located in the borehole, for example is driven by a drilling turbine.

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copy

In turbine drilling, the lower end of the drill pipe consists of a number of hollow pipe sleeves, which are each attached to one another with their end faces within the borehole and through their interior the Drilling fluid is pumped in from the surface of the earth. The drilling fluid passes through the drive turbine of the Drilling turbine assembly through and drives the drill head in this way. The drilling fluid then sweeps over one ^ usually in cross-section annular flow path to

Earth's surface back, which is formed between the outer walls of the rod sockets and the inner wall of the borehole is.

In directional drilling, is inserted into the drill string immediately above the drilling turbine an elbow part which has the shape of a drill sleeve, the drilling fluid is pumped through the interior thereof and W is mounted on one end of a direction angle determining oblique end face, whereby the drill within the azimuth plane of the the drill head containing rod section is deflected to one side.

The end of the elbow portion of the drill string provided with the beveled face is commonly referred to as

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"Knee". The other end of the knee section remote from this knee has a certain surface area on the inner wall of the borehole. This area is generally referred to as the "knee support surface". The knee piece So suffers a reaction force on the inner wall of the borehole and has on the knee contact surface on the inner wall of the borehole a fulcrum. As a result, a bending moment is applied to the drill in the azimuth plane of this rod section exerted, which acts on the drill head in the form of a force acting laterally in the drill head direction.

When drilling holes with a small diameter, for example when drilling holes with a clear Width of about 23 cm, the elbow section and the drilling turbine are usually not very much smaller than in diameter the drill head; for example, these parts therein have a diameter of about 20 em. "However, the borehole diameter larger, the difference in diameter between the diameter of the drill head and the diameter of the drilling turbine also becomes on the one hand and the diameter of the elbow part on the other hand correspondingly larger.

When drilling boreholes with a clear width of, for example, 30 cm, the drilling turbine and that Elbow part has a much smaller diameter than that

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Drill head; for example, this smaller diameter can be about 20 cm. With such dimensions, this is the elbow part angle about 1 ° to 3 * so the elbow part rolls when the azimuth direction by corresponding rotation of the upper Strand of the drill string is changed, with the substantially cylindrical knee contact surface on the inner wall of the borehole. Since the drill head cannot move sideways and the drill rotates freely with its shaft can, has this rolling of the knee contact surface of the knee part on the inner wall of the borehole with the result that the drill is laterally within the desired azimuth plane is deflected, but on the same side the drill head will tend to deviate in the opposite direction. It will If the drilling torque is changed, the elbow part will again have the tendency to the extent to which the drill string is twisted or twisted in the opposite direction to roll on the inner wall of the borehole. This will the control of the desired azimuth direction of the drill head path is uncertain.

The object is to be achieved by the invention, using elbow parts of the general type set out at the beginning Design a better compliance with the azimuth direction when To enable directional drilling.

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This object is achieved according to the invention in that the elbow part body is curved in the transverse plane running, at least part of the knee contact surface of the Elbow part forming surface area and also resting on the inner surface of the borehole, on both sides of the plane containing the angle of direction of the elbow part located, also in the transverse plane arcuate guide surface areas that also the largest The width of the elbow part in the direction perpendicular to the plane containing the direction angle is essentially the same, however, is smaller than the diameter of the drill head with which the elbow part is used, and that the elbow part is provided with means for connecting a drill at one of its front ends, which cause the drill center in of the plane containing the direction angle, but with reference to the center line of mass of the elbow part in this way Is offset towards the knee contact surface that the minimum distance between the drill center and this knee contact surface is equal to the drill radius.

An elbow part constructed in this way according to the invention will endeavor due to the system its guide surface areas on the inner edge of the borehole to slide rotatingly within the borehole and this effect is further improved in that in

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Further development of the invention, these curved guide surface areas of the knee part together with the likewise curved knee area of the _; Elbow part form a curved surface, the Querprdfil forms a continuous arch. · '

The knee piece according to the invention "is made as large as possible in the transverse plane, but without the annular channel serving to return the drilling fluid inadmissibly strong is throttled. This also ensures that all possibly occurring above the elbow part Lateral vibrations of the drill string before they are transmitted to the drill itself, at least partially be dampened. ·

One end of the elbow portion of the present invention, preferably the upper end, in use, may be cylindrical and have in comparison to the knee contact surface area smaller radius, whereby the catching of the elbow part and lies W drill is facilitated in the borehole. This end part, which is smaller in diameter with respect to the main body of the elbow part, is preferably eccentric with respect to the main body of the elbow part, while the central bore of the elbow part is arranged concentrically to this end part.

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The elbow part according to the invention can be made of rod material of only slightly larger diameter than the bore diameter, in which case the side facing away from the knee contact surface of the elbow part of the elbow part is made smaller in terms of dimensions, so that a flow path remains free for the backflow of the drilling fluid.

In a modification of this, the elbow part according to the invention can be made of rod material, which is much smaller in diameter than the inside diameter of the Borehole is so that from the start a backflow 3 for the drilling fluid remains free. In this case, it must be ensured that the knee part is in the area of the knee has a larger radius of curvature,

^V be formed According to another variant of the invention may guide surface areas of the invention to G-estängemuffen which are attached to a hole formed in a conventional manner elbow part of the Richtbohrgestänges.

The invention will now be described with reference to the accompanying Drawings in their details, for example

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described. The drawings show: -

Fig. 1.-.- '. a schematic elevation of one

"- -. Elbow part according to the invention for Richtbohrgestängej

FIG. 2 is a plan view of that shown in FIG Elbow part together with an associated drill hole .. : cross-section,

Fig. 3 is a schematic plan view of a

- Modified embodiment of a

Elbow parts according to the invention

Fig. 4 is a schematic plan view of a

further modified embodiment of a knee piece according to the invention "-teilesj

Fig. 5 'is a schematic elevation of a

An even further modified embodiment of a knee piece according to the invention and

Fig. 6 is a schematic plan view of the

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in Fig. 5 shown elbow part according to the invention.

, In Figs. 1 and 2, an elbow part is shown, which is suitable for use when drilling a borehole a clear width of about 31 cm using a boring machine with a diameter of 20 cm. The knee part body 1 has essentially cylindrical in shape and has an inclined end face 2 at one end. With this one The embodiment to be described is the elbow part made of solid material originally 90 cm long and approximately 26 cm in diameter. The center line of the original raw part is indicated at A. One area 3 the surface of the elbow part body 1 from an un- ' has a length of 30 cm with reference to the center line A. a radius of curvature of 13 cm. An end part 4 of the elbow part, The length of the hole required to catch it is approximately two feet and one with respect to the center line A smaller radius of curvature of 10 cm. Also has the elbow part is centered on the center line A and penetrates the elbow part over its entire length Hole 5 with an inner diameter of about 8 cm. In the knee contact surface is formed in an area 6 of the knee piece that is remote from the inclined end face. This area is machined round with reference to a center line B with a radius of curvature of approximately 14 cm

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consequently corresponds essentially with regard to its surface curvature, but the radius of curvature of the borehole 7 ' is smaller with reference to this. The center line B is. offset with respect to the center line A in the direction of the beveled end face so that the circles forming the profile of the surface 6 and the profile of the end part 4 on the knee system f smile side of the knee part at point C have a common tangent. The center line of mass of the larger part of the elbow part body 1 is therefore eccentric with respect to its central bore and with respect to the part 4 serving to catch the elbow part and consequently allows a greater deviation of the drill tip. This in turn makes it possible to make the directional angle of the elbow part larger, and this in turn makes it more reliable to control the directional deviation desired in each case.

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It goes without saying that means must be provided by means of which the elbow part according to the invention can be connected on the one hand to the rod sleeves and on the other hand to the drilling turbine. Have these resources usually in the form of screw threads 8.

If, when using the elbow part according to the invention, the azimuth direction, ie the direction of the deviation of _:

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Bohrers, changed, the knee part also tries to roll along the inner wall of the borehole. This rolling is prevented by the fact that the surface areas 7 of the surface of the knee piece body 1 already bear against the inner wall of the borehole and consequently the knee piece will tend to slide with respect to the borehole instead of rotating within unroll the same. Hitting provision that these surface areas are a natural continuation of the curvature profile of the knee abutment surface, so this Gleitbestreben is further increased, and also '.lCese £ Gleitbestreben will be the greater, the more the maximum width of the elbow part _s d "h" is the distance between the two flat areas 7 on a line perpendicular to the plane of the deviation direction, the diameter of the borehole or that of the drill head approximates.

The elbow part according to the invention described above has a number of advantages:

1), characterized in that the _s; The curvature of the knee contact surface is as close as possible to the curvature of the B.ohrlochinnenwanäung 5. the Xniestüokteil- has the tendency to slide along the inner wall of the borehole when the azimuth direction is changed. So the drill xfird

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always in the plane of. Azimuth direction deflected and curved, which improves control of the drilling direction,

2) Since the knee contact surface of the knee part according to the invention . is larger than that of the hitherto known elbow parts, occurs in spite of the invention The desired sliding effect does not show any major local wear of the knee section in the area of the knee contact surface. Changes in azimuth direction can therefore be performed gently without a There is a risk that you will see the elbow part on bumps the inner wall of the borehole jammed.

3) Because the elbow part according to the invention has a large eccentric mass, vibrations emanating from the rod string located above the elbow part are suppressed to a large extent and the inventive sliding of the elbow part results in the area of its knee contact surface within the borehole a friction damping with respect to the top of the drill. ' [-

4) The process of withdrawing the drill from the. Borehole

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bending moment exerted on this is reduced, because in the inventive design of the elbow part a limited lateral space within the bending plane for movements within this bending plane is available.

5) The elbow part according to the invention can despite its large in size and easily caught despite its physical eccentricity.

6) The elbow part according to the invention is opposite hitherto customary elbow parts not more expensive, because hardly any additional machining operations are necessary in its manufacture.

The means for connecting the drill and the drill string have to the knee part according to the invention in the usual way the shape of screw threads, each on the end End faces of the elbow part are attached. As a modification of this, the end parts of the elbow part can also be used protruding pins with external threads provided.

In the case of the arrangement of screw threads, these expediently colinear with the axis of the ■ inner bore of the elbow part arranged, which in turn around a

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Drilling radius is removed from the knee support surface, so that the housing of the drill at the transition point has a common tangent with the knee contact surface of the elbow part.

3 and 4 'show modified possibilities the knee piece according to the invention in conjunction with the Production of holes with a clear width of 31 cm · to be able to use. . ''

The borehole is indicated in FIG. 3 by line 5.

The elbow part body 1 is in this embodiment ■ an elbow part according to the invention made of round material with a diameter of 29 cm. The knee contact surface 10 of the lower part of the knee piece part according to the invention has a radius of curvature of 14 cm with reference on the center line A of the round body. The opposite face of the lower part of the invention Elbow part has a radius of curvature of 14 cm with reference to a center line B, which with reference to the Center line A by 2 cm towards the knee support surface is offset. In this way, there is a return flow channel for the drilling fluid return along the borehole 5 upwards.

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COPY

The centers of rotation of the cylindrical upper part 12 of the elbow part according to the invention, which has a diameter of 20 cm, and the inner bore 13 with a clear width of 8 cm coincide with the axis B. At at both ends of the elbow part its bore 13 widens into an internal thread not shown in the drawing .

Fig. 4 shows a further possibility of producing an elbow part according to the invention from a solid material originally 29 cm in diameter. In di - = *; = ™ rail has the in the lower part of the elbow part according to the invention formed knee contact surface 20 has a radius of curvature of 14 cm with reference to the central axis A of the round material. However, the opposite surface is provided with two flats 21, which in turn leave a through-flow cross-section 22 for the return flow of the drilling fluid upwards.

The upper part 23 of the elbow part according to the invention is turned to 20 cm with reference to a center line 2, this center line B being offset by 2 cm in relation to the center line A in the direction of the knee contact surface and the bore 24 of the elbow part also with Bezu ·; on this center line B is drilled.

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COPY BAD ORIGINAL

The embodiment of an elbow part according to the invention shown in FIG. 5 can be carried out in the simplest possible manner. be produced in that an already existing elbow part with an outer diameter of 20 cm is used and very few machining operations are carried out at a very low cost.

According to this embodiment of an inventive Elbow part are two rod sleeves 31 with about Attached to the elbow part over a central angle of 120 ° extending flats. These two rod sleeves represent that part of the elbow part body which has the guide surface areas which are described with reference to FIG the plane of direction of the elbow part according to the invention lie symmetrically. The greatest width of the inventive Elbow part along a perpendicular to this plane ver-_ The running line consequently corresponds to the line A-A indicated in FIG. 6 and this width should be approximately one centimeter be less than the clear width of the borehole.

The drill itself is made using the usual internal thread the drilling fluid bore to the axis at right angles to the knee section extending end face 32 attached, so that the Center of the drill with respect to the center of mass of the whole Elbow part, in the direction of the knee contact surface 33

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is offset and thereby the drill tip is deflected.

The rod sleeves 31 can either be welded to the elbow part body or, for example, by means of Screws can be detachably attached to the same, so that they can be adapted to different drill head diameters or can be exchanged for different borehole clearances.

In general, it is advantageous to place the drill on the end face of the knee part, which runs at right angles to the knee part axis, since the contact then taking place between the knee support surface of the knee part and the inner wall of the borehole takes place at the top of the knee part, while the lower part of the knee part and consequently the drill tip from the Borehole inner wall are pushed away, so that there is no risk of the drill being damaged. If the drill is placed on the inclined end face of the knee section according to the invention, the drill must not protrude beyond the profile curve that defines the knee contact surface.

In the embodiment of an elbow part according to the invention shown in FIG. 5, the two guide surface areas likewise protrude close to those of the knee contact surface

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■ "." "Ί904913

opposite borehole inner wall and consequently vibrations which occur along a plane extending to the line AA are effectively damped.

909137/02

Claims (8)

* t t «t claims 1. Elbow part for directional drill rods, with a inclined end face that determines the direction angle, characterized in that the elbow part body (1) a curved in the transverse plane, at least part of the knee support surface (C) of the knee section forming surface area and also on the inner surface of the borehole (7) on both sides the plane containing the angle of direction of the elbow part, which is also arcuate in the transverse plane Pührungs surface areas (6.) has that also the greatest width of the knee part in the direction perpendicular to the plane containing the direction angle im is essentially the same, but smaller than the diameter of the drill head with which the elbow part is used is, and that the elbow part with means for connection a drill is provided at one of its front ends, which cause the drill center to be in the plane containing the direction angle, but in such a way with respect to the center of gravity of the knee part in the direction of The knee contact surface is offset so that the minimum distance the middle of the drill from this knee contact surface is equal to the Drill radius is. - 19 - -, .-. ^ 909837/0242 2. Elbow part according to claim I _9, characterized / that its means for connecting a drill hold it at the front end of the elbow part which is opposite to the sloping end face (2) of the knee part. 3. Elbow part according to claim 1 or 2, characterized in that its means for connecting a drill Have the form of a screw thread. - ■ - · "'. "4. Elbow part according to claim 3» characterized in that the screw thread has the form of an internal thread arranged at the relevant end of the elbow part. 5. Elbow part according to claim 3 or 4 - characterized in that the screw thread central axis (A or B) is located at a distance of the drill radius from the knee contact surface (C). ' 6. Elbow part according to one of claims 1 to 5, characterized in that the two guide surface areas (7) are formed on separate parts (31) which can be separated from the elbow part body (1) (FIGS. 5 and 6). - 20 -. 909837/0242 fc * «ι * kk ..- ,. 7. Elbow part according to one of Claims 1 to β, characterized in that the profile is arch-shaped running surface area (C) and that of the two guide surface areas (6) together form a continuous Form arches (Fig. 1 to 3). 8. Elbow part according to claim 7, characterized in that said continuous arc is that of a cylinder profile (Figs. 1 to 3). - 21. - 909837 / 02A2