NL1025298C1 - Borehole measuring system for measuring drill head orientation, used for horizontal drilling, comprises strap down inertia measuring system - Google Patents

Abstract

The azimuth angle of the drill head relative to geographic North, the drill head angle of inclination and the drill head roll angle are continuously measured during drilling using a strap-down inertia measuring system. A borehole measuring system continuously measures the azimuth angle of the drill head relative to geographic North, the drill head angle of inclination and the drill head roll angle during drilling. This is achieved using a strap-down inertia measuring system.

Description

Title: Borehole inertia measurement system placed on rotating platform with a degree of freedom. BACKGROUND

Horizontally controlled drilling is a method used to construct an underground infrastructure, such as cables and pipes, without making slots from the surface. A borehole is drilled underground at precisely predetermined positions. After this borehole has been cleared, the cable or pipe cr is retracted. Slit-free horizontal steered drilling is used in urban areas or for laying an infrastructure under a river or railway line. 10 The underground infrastructure is becoming increasingly busy. This requires precise navigation during drilling to prevent collisions with existing infrastructure. Logging in of the underground infrastructure takes place in three steps. First drilling is done, then the drilled hole is cleared, so that finally a pipe or cable can be pulled through the cleared borehole. During the pre-borra, the drilling machine operator must drill precisely via the predetermined underground drilling path. The operator is assisted by the measuring system, which determines the position of the drill bit relative to the desired trajectory. The core of this measuring system is the measuring system behind the drill bit, which measures the spatial orientation. This orientation measuring system measures the azimuth, the angle of inclination and the log of the drill bit.

The invention relates to an inertia measuring system, which with a degree of freedom on a platform 20. is mounted so that the orientation of the drill bit can be measured continuously during drilling. Many methods for measuring the borehole after the withdrawal of the underground infrastructure already exist, these measurements are called surveys. The survey measurements differ from the measurements during the predrilling. The biggest difference is that during pre-drilling the drill rod rotates, as does the inertia measurement system. During the survey measurement, the measurement system is pulled through the laid underground pjjp or tube, without this measurement system rotating. Moreover, there are almost no vibrations as they do when measuring during pre-drilling.

Current measuring systems for measuring the position of the drill bit during the leg drilling are based on the use of the earth's magnetic field and the gravitational force field, as an orientation reference. The orientation is measured with respect to the earth's magnetic field, characterized by the local dip angle and the local field strength. Acceleration sensors are used to measure (the angle and angle of the drill bit, while the azimuthock is measured with respect to said local magnetic field vector. This method has the disadvantage that disturbances of the earth's magnetic field lead to erroneous values of the azimuth angle. the earth's magnetic field are caused by electrical cables, catodic protection of underground pipes, magnetic materials, etc. Some systems use an artificial magnetic field for which the position of the drill bit is measured. The greater magnetic field strength, which is determined by a current-conducting reference. wire is generated, this system makes it less susceptible to disturbances, but disturbances remain, and for the sake of this metiqg 1025298

I 2 I

I an electrically conductive wire is laid over the surface of the drilling path. At railway lines I

I or in urban areas this is often not possible. Still other measuring systems are based on an I

I beacon radio in the drill bit. At the surface, with a receiver, the angle and taper down to this I

I beacon measured. Both the latter system and the systems using an artificial I

The magnetic field has the disadvantage that it is difficult to use large bean pods in urban areas

I areas with densely built-up areas, by river crossing etc.: I

The invention uses an inertia measuring system, wherein the disadvantages mentioned and I

I disruptions do not occur. Such systems already exist for survey measurements, but use I

I make mechanical gyros. The disadvantage of these mechanical measuring systems is the I

I 10 sensitivity to shocks and vibrations. Practically no shocks occur in the survey application and I

I vibrations, but these are strongly present during pre-drilling. In addition, the I

Mechanical gyroscopes insufficient accuracy due to the so-called acceleration dependent I

I drift. The invention uses optical gyroccopcn, such as Fiber Option Gyracopcn and Ring laser I

I Gyroscopes, as part of the inertia measurement system, are not affected by the I

I 15 acceleration forces. I

SUMMARY OF THE INVENTION

I The angle of inclination, ridge angle and azine angle of the drill bit can be determined during drilling. I

I by using a strap-down gyroscopiscfa system with at least three axes around the I

I to determine angular velocities and at least two axes to determine the angle of inclination and the log. I

I The system usually consists of three angular cleanliness sensors mounted mutually perpendicularly and three I

I mutually perpendicularly mounted sensor sensors. I

Although the zero point shift of optical gyroscopes can become good I

I minimized with advanced techniques, the schaaHactor fbut cannot become sufficient

I 25 compensated. In general, the drill rod is constantly rotated around the I during drilling

I have the drill bit drilled. However, continuous rotation of the inertia measuring system, together with the drill bit, I

I leads to an ever increasing fbut in the longitudinal axis direction of the gyroscope due to the I

I scale vector fbut of the gyroscope. As an example, the rolling angle fbut increases by 2 degrees after 10 l

I turning the drill bit for a minute at a speed of 60 revolutions per minute in the case of a rear error I

I 30 of the gyroscope of 10 ppm (0.001%). In addition, a faulty alignment of the gyroscope would axes I

I of, for example, 10 micro radians lead to an angular velocity error of 0.0036 degrees per second at I

I relative to the perpendicularly placed gyroscope. The latter would make the North Search impossible. I

I during drilling, because the angular velocity of the earth relative to the North / South axis with an I

I accuracy of 2.8 exp-6 degrees per second must be measured to the desired I

I can obtain accuracy of the azimuth angle relative to the geographical North. This I

I explains why in the traditional so-called "measurement during drilling" ("MWD") applications do not I

I can be measured continuously during drilling. I

The invention relates to the mounting of the inertia measuring system on a platform with 1 degree (1 I

I DOF) of freedom. The platform can be rotated by a motor. The motor is set in angular position I

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3 controlled by the measurement with the inertia measurement system. The rotary axis of the hst platform is parallel to the rotary axis of the drill rod. In this way it is possible to uncouple the drill rod rotation from the rotation of the inertia measurement system. Thus, the inertia measurement system will not run continuously during drilling. Thus the gyroscopes do not measure a continuous rotation, but only the rolling angle, angle of inclination and the azimuth book of the drill bit. This method is not applied more eater and allows continuous use of the inertia measurement system during drilling. An additional advantage is the extensive self-testing capability by chuckling the rotating platform for testing the gyroscopes and acceleration sensoran, while these are mounted in the drill pipe.

10 BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the drawings in which:

Figure 1 shows a schematic overview of the drill chuck with the inertia measurement system, the bootpgp with the eczKhaadsvcrbindfag for ekldriacho feeding and bi-the-signal transfer, as well as the above-ground drilling machine, signal receiver and signal processing;

Figure 2 shows an overview of the inertia measuring system mounted on the motor-driven platform, as well as the micro-controller signal transmission.

DETAILED DESCRIPTION OF DB INVENTION 20 With reference to Figure 1, an earth surface 1 is shown. The drill hole is located under the surface and in the ground 2. The drilling machine 14 rotates the drill rod 12 during drilling and at the same time this drill rod is pushed forward by the drill. The drill rod consists of a number of steel or aluminum pipes, which are connected to each other with screw threads. Each pjjp has a length of 3 to 9 meters. The drill rod rotates at a speed between 0 and 80 tokens per minute. At the front of the boom hose is the drill icop 3, which cuts away the soil and flushes away. The drill rod can be a so-called jet-head or a drill motor. The drill rod is a pipe with a flushing force pressed through this pipe for flushing the soil away from the drill bit. Steering is done by stopping the rotation of the drill rod and placing the drill head under a certain toll booth. As a result of this determined rolling angle east a tangential steering screw at the push of the drill head through the drill machine. The steering force escapes due to the design of the drilling icop. As a result, the rolling angle determines the direction of the control force acting tangentially on the drill bit during the pushing drive through the drill.

The drilling machine operator is responsible for the bending process and controls the drill bit over the predetermined underground path. This is done by operating the drilling machine. The drilling machine operator needs information about the actual underground route. This information is constantly needed during drilling and steering. The trajectory calculation is done in the calculation unit 6. The information for this calculation unit is given by the inertia measurement system 11, which is placed directly behind the drill bit 1025298 I 4

The inertia measurement system 11 measures the azimuth angle with respect to the geographical North, I

I as well as the roller angle and the slope angle. The total stroke of the drill rod is measured on the I

I bean machine with a length measuring system 15, which is connected to the computing unit 4. Based on I

I calculates these parameters from the actual underground trqject Pc calculation unit I

I 5 compares the actual trajectory with the predetermined desired tnyect The difference between the I

The desired and actual route is calculated by the calculation unit and others

I shown on the display 6. The display information is used by the drilling machine operator to I

I to steer the booikop to the desired tnyect or to adjust the boat head to the desired trqject

I love. I

The controlled drilling described above takes place during pre-drilling. If it is drilled I

I is ready, the drill chuck and the inertia measuring system are removed and an I is applied to the I

drill rod mounted. This reamer is retracted with the drill rod with the te

I install underground pipe or cable. Survey measurements take place after the pre-drilling is finished, I

I either by stapling through the drill rod or by measuring through the final underground p $ p or I

In contrast to the inertia measuring system mentioned in this invention, the inertia rotates

I measuring system for the survey should not be measured. I

The parameters measured by the inertia measurement system, azimuth angle, angle of inclination, etc. roll angle, I

During drilling, I become continuous through the transmitter * via a one-wire veriadia clean through the boocpyp 12 I

I sent to the receiver 13. The underground inertia measuring system contains the inertia I

20 sensors 10, a microprocessor 9 and a batterq power supply 7. The better power supply takes the power supply I

I for the inertia measuring system from the above-ground feed 5, when the drill pipes are turned

I loegeefaroefü when fitting the following drill rods on the drill. I nutrition

I power supply 5 took battery® 7 done by the same single-wire vibration used for the I

I signal transmission between transmitters / receivers S and 13. I

Drawing 2 shows the invention in a schematic form. The gyroscopes and acceleration desires I

I form the inertia measurement system 16. The motion measurement system is placed on a 1 degree I platform

I of freedom, indicated by the alloy 23. The servo motor 17 can rotate the inertia measuring system I

I relative to the boocpyp. The sovo-regidaw 20 sends the power to the senKMnotor. Sensor 24 I

I measures the relative angular position of the inertia measuring system with respect to the drill pipe. This measurement I

I contactless and necessary to be able to measure the absolute rolling angle of the drill bit via the I

I tated measuring system. The feed to the inertia measurement system takes place via dragrtagcn 18. Dc I

I measurement signals are sent to or received from I via slip rings 19 of the inertia measurement system

I the micro-controller 21. The micro-controller 21 calculates the required rotational speed of the servo motor I

I time axis drilling. I

The azimuth angle measured by the micro-controller, the measured angle of inclination and the measured and I

I calculated roller angle, are continuously transmitted via the transmitter / receiver 22 via the one-wire connection to the I

I receiver / transmitter placed on the surface. The transmission is bi-directional, so that I

I can be sent from the surface test signals to the inertia measuring system. I

I I

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In addition to the aforementioned parameters azimuth angle, inclination angle and roll angle, status parameters, ab temperature, feed condition, vibration level etc. are also sent to the surface receiver.

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Claims (6)

1. Borehole measuring system for continuous measurement during drilling for measuring the azimuthock of the drill bit relative to the geographic North, and measuring the angle of inclination and rolling book of the drill bit by means of a strap-down inertia measurement system. 2. System as claimed in claim 1, further comprising a platform, with 1 degree of free-swinging rotary axis of the drill bit, for mounting the inertia B measuring system. 3. System as claimed in claim 2, wherein the platform is driven by a motor 10 and wherein the angular position of the inertia measuring system with respect to the drill bit is measured AwMnflnwtiiAaiiiMMiif 4. System as claimed in claim 3, wherein the motor is controlled by a microcontroller, which receives information for this control from the inertia measuring system, so that during drilling the iatertion measuring system does not rotate with respect to the earth. I 13 5. System tracking »claim 4, wherein the information from the intertk measurement system I is used in the mioo controller for stably controlling the motor for rotating the platform. The system of claim 1 for transmitting and receiving data, as well as electrically feeding the inertia measurement system through a one-wire electrical connection. I 1025298