(51) Int.Cl.2: E 21 C, 9/00

July 28, 1977

The copy of the document

shall not be amended.

Patent Claims

1.) Stabilizer, which is intended for deep hole drilling in underground and open pit mining operations and which automatically maintain the predetermined drilling direction, said stabilizer consisting of an inner tube, bearing the drilling tool, and an outer tube, which is mounted in a rotatable manner on said inner tube and which is provided with guide bars and contact elements, characterized in that the stabilizer consists of the internal drill pipe (1, 3) and the direction measuring pipe (5), which is mounted in a floating manner on the machine side of said drill pipe and which is provided with guide bars (8, 9) and leaf springs (10) on the periphery, as well as consists of the control housing (6), which is mounted on the tool side between the two pipes, and in which a plurality of control valves (12) - which are distributed uniformly over the periphery and which are always supported with their pistons on the direction measuring pipe (5) - and the working pistons (13), which are in hydraulic contact with said control valves, are arranged in such a manner that in the event of a deviation from the drilling direction, the control valves (12), located in the direction of the deviation, are opened by the direction measuring pipe (5); and, as a result, the pressure of the circulation fluid over the assigned working pistons (13) causes a restoring force to be exerted on the direction measuring pipe (5).

2.) Stabilizer for deep hole drilling, as claimed in claim 1, characterized in that the control valves (12) lie with their pistons without play in the internal borehole of the direction measuring pipe (5) when the borehole runs in a straight line, but as soon as the direction of the drilling tool changes,

the control valves are lifted off, thus releasing the path of the pressurized circulation fluid to the working pistons (13), the latter generating, subject to the action of the pressurized circulation fluid, a radial displacement force and in this way restoring the initial direction; and upon reaching the initial direction, the control valves (12) close again subject to the pressure of the circulation fluid.

3.) Stabilizer for deep hole drilling, as claimed in claim 1, characterized in that there is a force locking, radially moveable, dirt impermeable connection between the direction measuring pipe (5) and the control housing (6).

4.) Stabilizer for deep hole drilling, as claimed in claim 1 and 3, characterized in that in the case of full hole drilling the first drill pipe, bearing the drilling direction stabilizer, is equipped with a circulation fluid baffle plate (17).

5.) Stabilizer for deep hole drilling, as claimed in claim 1, 3 and 4, characterized in that in the case of core drilling, instead of the baffle plate (17), a smooth walled inner tube (18) is installed, so that there remains in the direction of the drill pipe (1) a ring groove (26) for the engagement of the axial securing of the wireline core pipe.

6.) Stabilizer for deep hole drilling, as claimed in claim 1, 3, 4, and 5, characterized in that in the case of full hole and core drilling, the following drill pipes are retained; in the case of full hole drilling they are equipped with dirt sieves (22); and in the case of core drilling, they are equipped with a smooth walled inner tube (24), instead of the dirt sieves (22).

Stabilizer for Deep Hole Drilling

The invention relates to a device, which guarantees that a predetermined direction of the borehole shall be maintained automatically during deep hole drilling, using not only the full hole but also the core drilling method, in open pit and underground mining operations in all existing soil formations. In particular, in underground mining, where frequently the exact location of the starting and exiting point of a borehole is carefully determined, it is extremely crucial that the borehole maintains the predetermined direction. Such drilling is generally called directional drilling. But even in the case of exploratory drilling, the purpose of which is to find unknown deposits, a straight line course of the borehole is very important. Exploratory drilling is carried out according to both the full hole and the core drilling method.

The present invention can be used for both methods.

To date one has tried to achieve the straight line course of a borehole by installing so-called directional drill rods. These directional drill rods are drill pipes with mounted guide bars; the outside diameter of the drill pipes matches the drilling diameter. Since these drill pipes follow the advancing drilling tool, they are supposed to guide it in a concentric manner. Directional drill rods exist in a variety of designs, such as the rigid design, where the guide bars are connected rigidly to the drill pipe and rotate together with the drill pipe in the drill hole. Or there are also designs, where the guide bars are mounted on a separate outer pipe, in which the actual

drill pipe is mounted in a rotatable manner. For vertical drilling there already exist directional drill pipes with a built-in automatic vertical control unit with simultaneous exploitation of the gravitational force and use of the pressure of the circulation fluid.

The useful directional drill rods, as they are still used today for all boreholes - be it during full hole or core drilling - that deviate from the vertical direction, are totally unsatisfactory, since they still allow an unacceptably high deviation of the borehole from the desired direction. The undesired deviations occur especially in the transition zones from hard to softer layers, especially in the event of an acute angle of impact. In this case the drilling tool advances with greater ease in the soft layers; similarly the downstream directional drill rods, which are equipped with guide bars. The deviation, which has been initiated as a result of the advancing drilling tool, becomes larger so as to form a parabola owing to the deflection of the following drill pipes, which are under compressive strain and which transfer the necessary feed pressure, generated by the external drilling machine, to the drilling tool.

In summary, it must be pointed out that with the current available means one is still not able, according to either the full hole or core drilling method, to bore a straight line horizontal borehole up to approximately 100 m without carrying out in the meantime directional measurements and to direct the drilling as a function of the determined deviation. These working steps are, of course, extremely time consuming and expensive, especially in the case of boreholes with a depth of 1,000 meters or more.

Another drawback lies in having to use two totally different drill pipe accessories and, thus, machine accessories for full hole and core drilling, according to the wireline core drilling method.

The object of the present invention is to remedy the aforementioned drawbacks and to propose a stabilizer, which is intended for deep hole drilling and which in the event of a deviation from the predetermined direction of the drill hole automatically corrects the direction of the drilling tool. In this case the same type of drill pipe can be used for both full hole and core drilling, according to the wireline drilling method. The solution to the problem consists of the fact that the stabilizer consists of the internal drill pipe 1, 3 and the direction measuring pipe 5, which is mounted in a floating manner on the machine side of said drill pipe and which is provided with guide bars 8, 9 and leaf springs 10 on the periphery. Moreover, the stabilizer consists of the control housing 6, which is mounted on the tool side between the two pipes. In this housing a plurality of control valves 12 - which are distributed uniformly over the periphery and which are always supported with their pistons on the direction measuring pipe 5 - and the working pistons 13, which are in hydraulic contact with said control valves, are arranged in such a manner that in the event of a deviation from the drilling direction, the control valves 12, located in the direction of the deviation, are opened by the direction measuring pipe 5. As a result, the pressure of the circulation fluid over the assigned working pistons 13 causes a restoring force to be exerted on the direction measuring pipe 5.

One embodiment of the invention is shown as a schematic drawing in the attached figures; and the function is explained below.

Figure I is a longitudinal view of the inventive stabilizer for deep hole drilling with a control unit and radially arranged working pistons. The upper half of the drawing shows a core drill bit with an inserted smooth inner tube for drilling according to the wireline core drilling method; the lower half shows the construction for a full hole drilling tool.

Figure II shows the related extension drill pipe, again in the upper half for drilling according to the wireline core drilling method and in the lower half for the full hole drilling.

In Figure 1 the machine side of the drill pipe 1 exhibits a connecting thread 2 for the connection with the drill pipes 3 (depicted in Figure II), which are to be reset; and the drilling tool side of the drill pipe exhibits the receiving thread 4 for the drilling tools. The latter - that is, the drilling tools - may be faced with diamond or hard metal, as a function naturally of the hardness of the rock to be drilled, for both core and full hole drilling and/or are constructed as roller bits.

The direction measuring pipe 5 with the control housing 6 is mounted in a rotatable manner on the drill pipe 1. The direction measuring pipe 5 is mounted in a free standing manner on one side of a pendulum bearing 7 and bears on the outer periphery in the front and the back at least 4 guide bars 8 and 9 at a time. The outside diameter of the guide bars 8 and 9 matches that of the respective drilling tool. Furthermore, the guide bars are constructed in such a way that the drill cuttings can be removed from the drilling tool and sluiced between the individual guide bars by means of the anticipated circulation fluid.

Moreover, the direction measuring pipe 5 is equipped externally with at least 2 leaf springs 10 or the like. Said leaf springs are supported in a springy manner on the wall of the drill hole

and, thus, prevent the co-rotation of the direction measuring pipe 5. An elastic ring 11 is embedded in the direction measuring pipe 5, which is mounted in a floating manner. The elastic ring is supported in the front on the control housing 6 and, thus, protects the control mechanism from becoming dirty and simultaneously does not allow the co-rotation of the control housing 6.

In the front section the direction measuring pipe 5 is supported additionally on at least four - preferably 8 or more - control valves 12, which are arranged radially in the control housing 6. Said control valves in turn are in hydraulic contact with at least 4 - preferably 8 - working pistons 13, which are arranged radially in the control housing 6.

The pressurized circulation fluid is conveyed through the drill pipes to the drilling tool 14 or 14' and over the borehole 15 - sealed with the rotating seals 16 - to all of the valves, which are disposed on the periphery and have control pistons 12.

In the event that a full hole drilling tool is used, there is a baffle plate 17 with a suitably constricted passage cross section, so that the circulation fluid is pressed through the borehole 15 at the necessary pressure.

When drilling according to the wireline core drilling method, there is, instead of the baffle plate 17, a smooth walled inner tube 18 with a retaining collar 19 and a transverse borehole 20. In this case the smooth walled inner tube 18 is kept shorter than the drill pipe 1, so that after screwing together with the following drill pipe 3, the result is a ring groove 26 for the engagement of the holding mechanism of the wireline core fittings. At the same time a cross sectional constriction at the head

of the introduced wireline core barrel, which is universally known (not illustrated here), provides the static pressure that is necessary for forcing the circulation fluid through the borehole 20.

In the case of full hole drilling, the drill pipes 3 in Figure II that belong to the inventive idea are equipped on the drilling tool side with sieves 22 and on the machine side with a nonreturn ball 23. In the case of core drilling, there is, instead of the sieve 22 and the nonreturn ball 23, a smooth walled inner tube 24 with a retaining collar 25.

Operating Principle:

The inventive stabilizer for deep hole drilling is drilled in as a function of the desired drilling direction during the universally conventional drilling operation and drilled deeper by successively resetting the individual drill pipes 3. In so doing, the direction measuring pipe 5 with its guide bars 8 and 9 are centered in the borehole. In this case the leaf springs 10, which are supported on the wall of the drill hole, prevent the direction measuring pipe 5 and its connected control housing 6 from rotating concomitantly. In the case of a straight line run of the borehole, the control valves 12, which are under the pressure of the circulation fluid, are all supported without play in a corresponding recess of the direction measuring pipe 5.

As soon as the drilling tool 14 or 14' with the drill pipe 1 departs from the predetermined drilling direction, the control housing 6, which is not rotating concomitantly, is simultaneously displaced in the radial direction. During this radial displacement the piston - control valves 12 are lifted off on the corresponding side, so that the pressurized circulation fluid can drive the respective

working pistons 13. The latter - that is, the working pistons - are supported in the direction measuring pipe 5, so that the drilling tool is returned into the initial direction. As soon the initial direction is reached again, the control valves 12 are pushed by the pressure of the circulation fluid onto their valve seat and, thus, block any additional feed of circulation fluid to the respective working pistons 13. The control valves 12 are guided loosely in the passage borehole, so that there is a small amount of leakage that is sufficient to relieve again the working pistons 13, which had been driven. The discharged circulation fluid can escape through the borehole 27, which is protected against penetrating dirt by means of a nonreturn ball. It stands to reason that the leakage is dimensioned so small that when the control valves 12 are open, an adequately large cross section is exposed; and the pistons 13 are driven correspondingly.

In the case of full hole drilling or drilling according to the wireline core method, the operating principle of the drilling direction stabilizer of the invention remains unchanged. Only the internal equipment of the drill pipes has to be selected as a function of the applied drilled method. In the case of wireline core drilling the smooth inner tube 18 is inserted into the drill pipe 1 for the purpose of receiving the wireline core fittings (not illustrated). The inner tube 18 is locked into position with the retaining collar 19 axially by screwing in the drilling tool 14'.

The transverse borehole 20 serves for the passage of the circulation fluid to the control mechanism. The length of the smooth walled inner tube is dimensioned in such a way that in the direction of the drill pipe 1 and the subsequently screwed-on drill pipe 3, a ring groove 26 for the engagement of the wireline core fittings remains free, according to the method known in the prior art.

In the case of the drill pipes 3 in Figure II, the smooth inner tube 24 for wireline core drilling matches the full effective length of the drill pipes, so that when screwed together the result is a transition-free inner borehole. The inserted smooth walled inner tube 24 prevents advantageously the entrainment of existing pollutants, such as scaling internal rust or the like from the drill pipes 3, by the circulation fluid. This is very important, since no protective sieves 22 can be installed during wireline core drilling.

During full hole drilling the smooth walled inner tube 24 is removed from the drill pipes 3 and replaced with the sieve 22 and the universally conventional nonreturn ball 23. During upwards directed full hole drilling the nonreturn ball 23 has the task of preventing the backflow of the circulation fluid from the drill pipes, when said pipes are extended in succession. At the same time the sieve 22 prevents the circulation fluid from flowing through the nonreturn ball 23 during the drilling operation.

The expensive equipment - like drilling machine and drill pipes - will remain, according to the invention, the same in any event for both drilling methods.

It stands to reason that the invention can be implemented not only according to the illustrated solutions, but also according to a plurality of additional design solutions.