EP0798443A2 - Directional drilling method - Google Patents

Abstract

The boring machine bores via a remote controlled boring head (4). This is driven by concentric pipes with jointed sections (1). The rotation of the boring head is controlled to generate either straight line boring or curves. The latter are generated by varying the rotational speed. The boring head has water sprays and an eccentric cutting head. The bore obtained is smooth sided and has smooth curves. For straight line boring a constant drive speed is used.

Description

The invention relates to a method for directional drilling with the aid of a mechanically and / or hydraulically degrading drilling device, which makes it possible to work either straight or along a curved path.

Such drilling devices consist of a rotating and / or impact driven drill string with a drill head of very different designs. The drill pipe is usually mounted on a rail-guided slide connected to a linear drive and has a rotary or rotary impact drive with which the pipe can be set in rotation and, if necessary, also driven into the ground.

In order to enable directional drilling, such devices have an eccentricity which causes cornering but can be overcome when drilling straight ahead. This is done in such a way that the part having the eccentricity rotates at a constant angular velocity while drilling straight ahead, the effect of the eccentricity being lost. At the transition to curve drilling, the part that has the eccentricity or the drill head becomes one Angular position stopped for a certain time and remains in this angular position until the cam track is completed or as long as the specified cam track is maintained. If the drilling head leaves the intended trajectory, the angular position must be corrected until the trajectory is reached again and the drilling head must be adjusted to the trajectory again. In this way, the drill head generally has to be positioned several times with respect to its angular position in the course of a (longer) curve. Therefore, several angular steps of the linkage, which is otherwise not rotating during cornering, are always required. In this way, a zigzag or corkscrew-shaped earth hole is created, but no exact curved path.

The respective angular position of the eccentricity depends on the direction of curvature of the borehole to be drilled, but the eccentricity is always on the inside of the cam track, where it unfolds the effect of a pivot point, while the opposite side when mechanically advancing the rod or the drill head by pushing and / or hitting - without rotation - as a shoulder or gliding shoe that acts in the ground like sliding along a guardrail. The soil in front of the drill head is laterally displaced by the drill head during rotation-free curve drilling and / or more or less broken down with the help of a sharp jet of liquid. However, this is only possible with floors that are not too firm and free of obstacles, which can also be displaced.

The type of drill pipe, the eccentricity and the drill head are very different in individual cases. For example, US Pat. No. 3,878,903 describes a device with a linkage composed of a rotatable outer tube and a driven inner linkage which is connected to a removal tool. The drill pipe is angled in the vicinity of the drill head and consequently permits curve drilling, in which both the curve radius and the direction of curvature can be changed by adjusting the angle of the drill pipe. With continuously rotating booms, straight drilling is possible with a considerably enlarged diameter of the earth channel. This diameter corresponds to the enveloping circle diameter of the drill head tip and is larger the more the front rod section is angled.

Furthermore, the European laid-open specification 0 247 767 describes a drill head connected to a rotating / pushing rod with an inclined surface, which allows drilling straight ahead as long as the drill head rotates uniformly and, without rotation, curves drilling by displacing the soil located in front of the drill head.

A similarly operating device is described in European Patent 0 195 559, the angled drill head of which, however, is provided with a concentric nozzle, from which a high-pressure jet emerges for loosening and removing the soil in front of the drill head.

In order to be able to locate the position of the drill head in the ground, a transmitter, for example powered by batteries, can be arranged in the drill head, which is provided with measuring devices that make it possible to determine the depth at which the drill head and where it is located in the ground. like the inclination and roll of the drill head with respect to its axis, ie is the angular position of the inclined surface with respect to the longitudinal axis. In addition, the temperature of the drill head can also be determined.

The measured data is transmitted from the transmitter located in the drill head to a receiver on the surface of the earth and displayed there. From there, the data is sent wirelessly to the operator at a turning and feed unit and is also displayed there. A steering maneuver can be triggered on the basis of this data.

The known methods and devices for directional drilling are all based on the principle that the drill pipe rotates while drilling straight ahead and accordingly the drill head describes an enveloping circle with a diameter that is larger, usually substantially larger than the drill pipe or drill head diameter while the drill pipe is moving does not turn during cornering and the drilling is done solely by thrust and / or impact.

During the transition from straight-ahead to curve drilling, an abrupt interruption of the rotational movement in a certain angular position of the drill head, which is predetermined by the direction of curvature, is required. Associated with it is an equally abrupt or sharp change in the direction of advance. This in turn is determined solely by the type and degree of eccentricity, for example the inclination of an inclined or steering surface on the drill head with respect to the main axis of the rod. Since the eccentricity or inclination is predetermined by design, corrective changes in direction during cornering are only possible in such a way that the angular position of the drill head or the eccentricity is changed by rotating the rod by a certain angle. Since several corrective changes in direction are usually required during cornering, the resulting earth channel runs more or less in a zigzag shape or - depending on the nature of the drill head - like a corkscrew. This has an extremely disadvantageous effect when the pilot bore is expanded later with the aid of an expansion head and / or when a pipeline is pulled into the pilot bore, because the earth bore runs irregularly in the particularly critical curve area and has an uneven wall that the expansion head and / or Pull-in tube opposes a high sliding resistance. This requires increased technical effort when expanding and pulling in. In addition, there is the instability of such an earth channel wall, which is associated with the risk of break-ins, increases the difficulties in expanding and pulling in pipes and, in particular, entails the risk of pipe damage when pulling in.

The invention is therefore based on the object to provide a method which is gentle and the linkage as well as the direction change that is gentle on the drill head and also results in a largely smooth-walled earth channel with a uniform curvature even in the curve area.

The solution to this problem is based on the idea of dissolving the steering step per curved track or section of track that is conventional in the conventional methods - without stopping the rotating drill pipe - into a large number of individual steering steps with minimal steering action, in order to achieve continuously controlled propulsion in this way.

In particular, the invention consists in a method for directional drilling with the aid of a drilling device with a rod and a mounted tool which moves on a circular path and which rotates when drilling straight ahead at a substantially constant angular speed, while during corner drilling the angular speed changes periodically temporarily with respect to a reference speed, ie is increased or decreased. The method according to the invention therefore works with a pulsating angular velocity during cornering.

The reference speed here is to be understood as the angular speed which would ensure straight-ahead drilling when drilling with a non-pulsating or constant angular speed and, in contrast, the change in angular speed according to the invention takes place. The changed angular speed represents the steering speed, which is only effective during a certain angular range.

A cornering can be done in such a way that the angular velocity is changed once per revolution. The change can be abrupt or continuous and / or take place after several revolutions. The more frequent the changes, the smoother and smoother the change of direction.

In the method according to the invention, the radius of curvature of cornering depends on the relationship between the reference speed and the steering speed, which determines the intensity of the soil mining and displacement on the two sections of the enveloping circle corresponding to the reference speed on the one hand and the steering speed on the other hand, which is determined during a rotation of the tool results.

If the change in the angular velocity in the method according to the invention is represented graphically over a time axis, then depending on the rate of change - with an abrupt change - a meandering curve and - with a constant change - a sinusoidal curve if the degree of the change in speed is the same in each case. However, this need not be the case; because it is also possible to work in phases with different changes in the angular velocity. However, the change in the angular velocity preferably takes place at the same time intervals as long as the cornering continues.

The steering effect can be further supported in the method according to the invention in that an acceleration impact or thrust is preferably exerted on the drill pipe and / or the drill head while rotating at the reference speed.

How the drill pipe, the drill head and the excavation tool are made is of no importance in the method according to the invention; the only decisive factor is that the drill head or the removal tool located on the drill head describes an enveloping circle during the drill rotation, and consequently there is an eccentricity or asymmetry.

Under this condition, several tools are possible for the method according to the invention, which are accordingly grouped eccentrically. Depending on the nature of the ground, a nozzle which delivers a cutting jet and is arranged on the axis of rotation can also serve as the removal tool.

However, a device with a driven drill pipe consisting of a curved guide or outer tube and a driven tool mounted in the guide tube is particularly suitable for the method according to the invention. The guide tube can be angled in a part adjacent to the drill head and / or can be provided with a steering surface. For the linkage and the drilling tool or the drilling head, a conventional drive is suitable, as is described, for example, in German patent specification 35 03 893 and is intended to be part of this description. As an alternative, however, it is advisable to include the drill head or the removal tool To drive hydraulically with the aid of a so-called Mud motor, to which a liquid medium, for example a bentonite / water suspension, which is also used as cooling liquid and / or transport medium for the mined soil, is supplied as the drive medium.

Mud motors can only be used to a limited extent, however, because their performance depends on the pressure or the amount of drive fluid supplied to them. Large torques and degradation capacities therefore require correspondingly large amounts of liquid, which pose considerable problems. If it is a - often thixotropic - bentonite / water suspension, then there are high costs for the bentonite consumption. In addition, the transport of the suspension through the drill pipe leads to heavy wear. Furthermore, the large amounts of suspension or water can lead to undesirable flushing out or, in the case of high hydrostatic pressure, to damage to the earth's surface, for example to roadways, if they remain in the ground, or they have to be returned, which means a corresponding pipe cross section in the drill pipe or a corresponding one Annulus between drill pipe and the surrounding soil and preparation for the reuse of the bentonite required. Finally, large amounts of liquid require a correspondingly large pump output, which is associated with high costs.

An external drive of the drilling tool or the drilling tools via a linkage, via which large torques can be transmitted, is therefore more advantageous. in the In the simplest case, the drill string consists of a preferably hollow string with an eccentrically arranged dismantling tool, which moves on an enveloping circle when the drill string is rotated. This can be done with the help of a slightly curved rod or with an arrangement of the drilling tool outside the axis of the rod or rotation.

The drill pipe can also consist of two concentric pipes, each with its own rotary drive. The inner tube is connected to the drill head or a removal tool, while the outer tube can be equipped with tools or can be provided with a drill bit.

In order to improve the soil mining and the removal of the loosened soil, the mining tool, the drilling head and / or the guide tube can be provided with nozzles for a liquid which is preferably supplied through the inner tube. The liquid can be used for cooling, for removing the loosened earth or in the form of a sharp jet for breaking down the earth.

The axis of rotation of the drill head or of the removal tool can be arranged eccentrically with respect to the rod axis in order to generate a tool movement on the aforementioned enveloping circle when the rod is rotated.

The loosened soil can be removed via an annular gap between the guide tube and the soil if the diameter of the excavation tool is larger than the diameter of the guide tube. Cheaper is, however, a discharge through the guide tube, for which there must be clearing openings in the drill head and / or in the guide tube. The internal discharge through the guide tube can be improved with the aid of a screw conveyor arranged there and / or by means of nozzles for a liquid.

On the other hand, there is also the possibility of swiveling the front part of the drill pipe so that it can work with different angles of inclination.

Fig. 1

eine für die Durchführung des erfindungsgemäßen Verfahrens geeignete Bohrvorrichtung in Aktion,

Fig. 2

ein Bohrgestänge mit abgewinkeltem vorderen Teil und einem Mudmotor,

Fig. 3

einem Ein-Rohr-Gestänge mit exzentrisch angeordnetem Mudmotor,

Fig. 4

ein Doppel-Rohr-Gestänge mit von einem Innenrohr angetriebenem exzentrisch angeordnetem Werkzeug,

Fig. 5

ein ähnliches Bohrgestänge, das sich für ein Innenabfördern des gelösten Erdreichs eignet,

Fig. 6

ein Doppel-Rohr-Gestänge mit abgewinkeltem vorderem Abschnitt und

Fig. 7

ein ähnlich beschaffenes Bohrgestänge, dessen vorderer Teil jedoch verschwenkbar ausgebildet ist.

The invention is explained below with reference to exemplary embodiments shown in the drawing. The drawing shows:

Fig. 1

a drilling device in action suitable for carrying out the method according to the invention,

Fig. 2

a drill pipe with an angled front part and a mud motor,

Fig. 3

a one-pipe linkage with an eccentrically arranged mud motor,

Fig. 4

a double-pipe linkage with an eccentrically arranged tool driven by an inner pipe,

Fig. 5

a similar drill pipe that is suitable for internal removal of the loosened soil,

Fig. 6

a double-pipe linkage with an angled front section and

Fig. 7

a similarly constructed drill pipe, the front part of which is pivotable.

In the method according to the invention, an earth hole 1 is made in the soil 2 by means of an elastic drill pipe 3 consisting of individual pipes. At the end of the drill pipe 3 there is a drill head 4 with a steering surface or bevel 5, which is connected to the drill pipe 3 in a rotationally fixed manner. The front edge of the bevel acts as a removal tool and describes an enveloping circle around the axis of the boom when the boom is turned. In the drill head 4, a transmitter 6 is arranged, which wirelessly transmits data to a receiver 7, which is based on the depth of the drill head 4 below the earth's surface, the location of the drill head 4 in the ground, its inclination, the angular position of the steering surface 5 with respect to the longitudinal axis of the Obtain the drill head 4 and, if necessary, the temperature at the drill head 4. A radio link between the transmitter 6 and a receiver 7 is indicated by the dashed line 8.

Another radio link 9 transmits the above-mentioned data from the receiver 7 to a display device 10 in the vicinity of a striking rotary and feed unit 12 arranged at the start 11. This rotary and feed unit 12 has a rotary drive 13 for the drill pipe 3, which acts on the drill pipe 3 Impact mechanism 14 and a feed drive 15.

The drill pipe 3 is coupled to the rotary and feed unit via a drill pipe connection 16.

A cable connection leads from the display device 10 to a switch box 17 with an operating panel, by means of which it is possible via a cable connection 18 in each case to control the rotary drive 13, the striking mechanism 14 and the feed drive 15.

The device shown in Fig. 1 can be operated in two different ways. If the drill pipe 3 is driven through the soil 2 in a rotating and pushing manner, a straight bore is created. The deflection of the eccentrically acting drill head 4, which is possible due to the steering surface 5 on the drill head, is thereby neutralized by the uniform rotation of the drill rod 3.

1 is initiated in that the rotary movement (angular velocity) of the drill head 4, for example in the region of the illustrated control position or angular position of the inclined surface 5 with respect to the drill string 3, briefly slows down to a certain steering speed during each rotation or is accelerated for a short time in the angular position offset from this position by 180 °. In this way, there is a curved curve downward as long as this periodic change in speed takes place.

The same effect can be achieved if the drill pipe consists of two concentric strands and on one of the strands where the steering surface 5 in one Tip or cutting edge ends, there is at least one tool that can be driven and moves on an envelope around the rod axis when the strand with which the tool is connected rotates. This is possible, for example, with a linkage consisting of two concentric tubes, in which the inner tube is provided with an eccentrically arranged tool or the outer tube is designed as a drill bit in a limited section of its end face.

In the exemplary embodiment shown in FIG. 2, the drill string consists of a bent drilling lance 19 with a bore 20, 21, which leads to a mud motor 22, which is supplied with drive fluid via the bore 20, 21. The mud motor drives a centrally arranged excavation tool 23 with nozzles 24, through which the drive fluid exits, in order to support the excavation of soil and / or to improve the removal of the loosened soil via the annular space 25 between the drilling lance 19 and the soil 2.

The drilling lance 19 contains a measuring and transmitting unit 26 for receiving and forwarding the measurement data required for steering.

Another one-pipe linkage 27 is shown in FIG. 3 and contains a mud motor 28 which is supplied with drive fluid via a hose line 29, which exits the mud motor via nozzles 30 of an eccentrically arranged removal tool 31. The front end of the drill pipe 27 is equipped with tools 32 and has a steering bevel 33, which is at a Cornering on the adjacent wall of the earth channel created by the tool 31. The cornering takes place when the drill pipe 27 is briefly rotated in the area of the angular position shown in FIG. 5 at a speed that differs positively or negatively from the reference speed.

The removal tool 31 can be driven as shown in FIG. 4 in a double-pipe linkage with an outer tube 34 also via a tubular inner linkage which consists of a plurality of sections 36, 37, 38 which are connected to one another by universal joints 35. The cardan joints can be omitted if the inner linkage is sufficiently flexible.

In order to improve the removal of the soil loosened by the removal tool 31 in cooperation with the liquid jets emerging from the nozzles 30, in the exemplary embodiment in FIG. 5 the outer tube 39 of the double-tube rod assembly 39, 40 has a spoil opening 41 and that is it Inner pipe 40 is fitted with blades 58 which convey the soil entering the outer pipe 39 through the excavation opening 41 in the direction of the drill pipe drive.

In the exemplary embodiment in FIG. 6, the guide or outer tube 42 of the drill pipe is angled, while the inner tube consists of a tubular string 43 which is connected via a universal joint 44 to an inner tube section 45 which is connected in a rotationally fixed manner to a removal tool 46. The diameter of the removal tool 46 is larger than the diameter of the guide tube 42 and therefore creates an annular space 47, via which the loosened soil and mixed with the liquid emerging via nozzles 47 of the mining tool 46 is conveyed away peripherally.

7, consisting of a guide tube 48 and a tube section 50 connected thereto via a joint 49, the removal tool 51 is driven via an inner linkage 52 which is connected via a coupling 53, for example in the form of a splined shaft, and a cardan joint 54 to the drive shaft 55 of the removal tool 51 is connected. A collar 56 of the inner linkage 52 is connected to the pipe section 50 via a push rod 57 and, when the inner linkage 52 is displaced longitudinally, allows the pipe section 50 to be pivoted. In this way, the bend angle of the pipe section 50 and thus the diameter of the straight section of an earth hole and the Infinitely adjustable radius of curvature when cornering.

All of the exemplary embodiments have one thing in common that a substantially uniform movement of the dismantling tool, which is arranged eccentrically with respect to the axis of rotation of the linkage, results in a straight drilling section on an enveloping circle around the axis of rotation and, when rotating with a preferably pulsating angular velocity, results in a curve, the radius of curvature of which depends on the geometry of the drill pipe and / or the drilling tool and the speed deviation in relation to the reference speed.

Claims (18)

Method for directional drilling using a drilling device with - a linkage and - A mining tool moving on a circular path, in which - Moving the tool when drilling straight ahead with a substantially constant angular velocity and - The angular velocity is changed periodically when drilling bends. A method according to claim 1, characterized in that the angular velocity per revolution of the Tool is changed once in a certain angular range. Method according to Claim 1 or 2, characterized in that the angular velocity is changed at the same time intervals during cornering. Method according to one of claims 1 to 3, characterized in that an acceleration stroke or thrust is exerted on the linkage at a time offset from the change in speed. Method according to claim 4, characterized in that the acceleration shock or thrust falls in the phase of the higher angular velocity. Device in particular for carrying out the method according to one of claims 1 to 5 with a driven drill pipe (3, 19, 27; 34; 39.40; 42.43; 48.50) and at least one tool (4; 23) arranged eccentrically to the drill axis ; 31; 46; 51). Apparatus according to claim 6, characterized by a drill pipe consisting of an angled or curved guide tube (19, 42) and a driven tool (23, 46) mounted in the guide tube. Device according to one of claims 6 or 7, characterized in that the drill pipe (3) consists of two concentric tubes (39, 40; 42, 43). Device according to claim 8, characterized in that the inner tube (36,37,38; 40; 52) is driven and connected to a removal tool (31,46,51). Device according to one of claims 6 to 9, characterized in that the tool (23, 31, 46) is provided with nozzles (24, 30, 47) for a liquid supplied through the inner tube (36, 37, 38; 40; 52) is. Device according to one of claims 6 and 8 to 10, characterized in that the tool (23, 31) is driven by a mud motor (22, 28) and the drive fluid is supplied through the linkage (19, 27). Device according to one of claims 6 to 11, characterized in that the linkage (19; 42, 43) is angled in the front part. Device according to one of claims 6 to 11, characterized in that the axis of rotation of the removal tool (31) is arranged eccentrically. Device according to one of claims 6 to 13, characterized in that the linkage (27, 34) or tool (4) is provided with a steering surface (5, 33). Device according to one of claims 8 to 12, characterized in that the front end of the Outer tube (27,34,39) with tools (32) is occupied. Device according to one of claims 6 to 15, characterized in that the linkage (39) is provided with at least one overburden opening (41). Apparatus according to claim 16, characterized in that a screw conveyor (40, 58) and / or nozzles for a liquid for removing the soil are arranged in the linkage (39). Device according to one of claims 8 and 15 to 17, characterized in that the outer tube (48) is connected in an articulated manner to a tube section (50) adjacent to the removal tool (51).

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