JPH0544517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control method for a mud pulse generator, and more specifically, to a method for controlling a mud pulse generator, and more particularly, a method for transmitting information about a well or a stratum to the ground from the bottom of a well being drilled in oil drilling or the like. The present invention relates to a control method for a mud pulse generator in a continuous bottom-bottom data thermetring system used as a means for transmitting data.

[Prior art]

Continuous bottomhole data telmetering system
This technology, also known as Measuring While Drilling (hereinafter abbreviated as MWD), has been in the spotlight in recent years, and has been in practical use in the field of oil exploration in the United States for several years. It transmits various information on the well or geological formation to the ground, such as the direction and angle of inclination of the tip of the drill pipe during excavation work, and the temperature and pressure at the bottom of the well.

The mainstream of MWD technology development is the mated pulse method, which has already entered the stage of practical use by several companies.The pulse-up method and pulse-down method are typical examples of this method. This is compared to the conventional method in which the above-mentioned information is obtained by suspending the detector from the tip of a wire and lowering it to the bottom of the well after all the drill pipes etc. are pulled up from the well while drilling an oil well. It will be increasingly put into practical use in the future as a measurement means that can reduce the work required to pull up drill pipes, etc., and improve the efficiency of excavation work.

Therefore, of the above two methods, the pulse-down method has a smaller valve in the pressure signal generator than the pulse-up method, requiring less driving force, and has a higher repetition rate of valve opening and closing, resulting in a lower data transmission rate. It has the advantage of being expensive.

Next, the principle of the pulse down type pulse generator of the conventional MWD will be explained with reference to FIG. A drill pile 2 is attached to the lower end of the casing 4 inserted inside.
An instrument section 5 is provided which has a built-in sensor to obtain information such as the direction of the inclination, the inclination angle, and the temperature and pressure of the bottom of the hole, and the information obtained by the instrument section 5 is transmitted to the ground as a pulse signal. , is calculated by a computer.

Therefore, in this pulse-down type pulse generator, a part of the high-pressure muddy water Mh pumped from the ground is pumped to the inner periphery of the bedrock 1 and the drill pile in order to assist the drilling by the bit 3 and to transport the drilling debris to the ground. 2
A mud water bypass passage 7 is provided that bypasses the mud water Ml in the gap between By opening and closing the muddy water bypass passage, the pressure of the high-pressure muddy water Mh drops rapidly, and the pressure difference generated at this time becomes pulse-down pressure and functions as a signal that is transmitted upward.

Figure 10 shows the relationship between the pressure of the muddy water Mh and time at that time, and the generated pulses are indicated by P, and the signal is modulated by changing the pulse interval.

The conventional pulse down method explained above
In the MWD pulse generator, solenoid 8
muddy water bypass passage 7 by the piston valve 9 and
Since the piston valve 9 is opened and closed, the piston valve 9 is controlled by turning on and off the current to the solenoid 8, and the force applied to the drive unit due to the pressure difference between the wedge-shaped opening and closing is reduced. is large,
There is a problem that driving power becomes large.

The characteristics that this type of pulse generator should have are a small driving force for pulse generation, a large amount of information to be transmitted, and excellent reliability. Conventional pulse generators do not completely satisfy these characteristics, and improvements in these characteristics are desired.

For this reason, the present inventors proposed that the bypass passage 7
Previously, we proposed a method in which a rotating stopper is installed inside and the rotating stopper is driven by a DC servo motor.

[Purpose of the invention]

In view of the above problems, the present invention provides a mud pulse generator of a type that generates pulses by opening and closing a rotary stopper, which has the advantages of requiring only a small driving force for pulse generation and having excellent reliability. To provide a control method for a mud pulse generator that can be extremely easily controlled and that can dramatically increase the amount of information transmitted by controlling the opening and closing of the rotary stopper quickly and accurately. The purpose is to

[Summary of the invention]

The control method for the mud pulse generator of the present invention is such that a drill pipe equipped with a cutter bit for drilling houses an instrument section for detecting the state of the cutter bit and the condition of the bottom of the pit excavated by the cutter bit. In a mud pulse generating device, the mud pulse generating device is provided with a casing and a bypass passage that allows a part of the muddy water that is pumped toward the cutter bit to escape to the outside of the drill pipe between the casing and the drill pipe. A rotary stopper for opening and closing, a motor for driving the rotary stopper, a sensor for detecting the open/closed state of the rotary stopper, and a switch switching circuit for generating an ON-OFF signal in response to a detection signal from the sensor. , a signal generator that generates a data signal according to data detected by the instrument section, and a signal converter that generates an ON-OFF signal by comparing the data signal with a predetermined reference value;
ON-OFF output from the switch switching circuit
Signal and ON-OFF output from the signal converter
and a switch for inputting an ON-OFF signal of the signal converter or a stop signal based on the reference value to a controller that controls the rotation of the motor. It is.

〔Example〕

An embodiment of a control method for a mud pulse generator according to the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 is a sectional view of a main part of a mud pulse generator employing a control system according to the present invention, and the same reference numerals as in FIG. 9 indicate the same names. A part of the high-pressure muddy water Mh in the drill pile 2 of the mine 6 is transferred to the low-pressure muddy water Ml.
Rotary plug 10 of muddy water bypass passage 7 bypassing to
This rotary stopper 10 is connected to a DC servo motor 11.
It is designed to rotate. This rotary plug 10 is provided with a T-shaped communication hole 12 as shown in Figures 2-A, 2-B, and 2-C, and the muddy water bypass passage 7 is connected to the
By repeating the open state shown in Figure A and the closed state shown in Figure 3-B, a down pulse pressure is generated in the high pressure muddy water Mh.

A rotating body 14 to which a magnet (to be described later) is attached is attached to a shaft 13 that connects the DC servo motor 11 and the rotary plug 10, and a box 15 in which a Hall element, a controller, etc. are housed is attached to the casing 4. .

To be more specific, as shown in the conceptual diagrams of FIGS. 4a, b, and c, the rotating body 14 has two magnets 16, 1
Hall elements 18 and 19 are provided in the casing 4 so that the angle between them is 90° at the center of the rotating body 14, and they are spaced apart from each other in the vertical direction. interval
It is installed with l′. That is, the rotating body 14
As the magnets rotate, the magnet 16 and the Hall element 18, and the magnet 17 and the Hall element 19, are installed so as to approach each other in the horizontal direction, thereby forming a detector for detecting the angle of rotation.

Figure 5 a, b, and c show the magnet 1 on the rotating body 14.
6 and 17 are arranged at 90° intervals only in the horizontal direction, while Hall elements 18 and 17 are also arranged inside the casing 4.
This is another example in which 19 is spaced at 90°. Inside the box body 15 is a signal converter 2 as shown in FIG.
0, analog switch 21, controller 2
2. In addition to the analog switch switching circuit 23, a power source (not shown) is provided. 24 in this figure
is a device that processes data from the meter section 5 shown in FIG. 1 to control the opening and closing of a rotary tap.

Assume now that the signal converter 20 is set to operate in the range of 0 to 5V. In other words, the command voltage
At 0V, the motor 11 rotates at maximum speed in the left direction, at a command voltage of 2.5V, the motor 11 stops, and at a command voltage of 5V.
The motor 11 is set so that the rotation speed is maximum in the right direction.

In such a state, the data signal detected by the meter section 5 is input to the signal generator 24,
In response to this data signal, a command signal of αV (2.5<α≦5) is sent from the signal generator 24 to the signal converter 20.
When the voltage is input to , it is converted into a 5V command signal, and this 5V command signal is input to the analog switch 21 . This signal is adjusted by the controller 22, and a voltage proportional to the command signal from the signal generator 24 is applied to the motor 11 to operate it in the right direction at the maximum rotation speed. When the rotary tap 10 shifts from the closed state to the open state and the output of the Hall element 19 reaches a certain voltage level, the analog switch switching circuit 23
Then, the analog switch 21 is switched from a to b, a stop signal of 2.5V is sent to the controller 22, the motor 11 is stopped, and the rotary tap 10 is opened.

On the other hand, the opening/closing control signal generator 24 for the rotary stopper 10
When a command signal of βV (0≦β≦2.5) enters the signal converter 20, it is converted into a command signal of 0V. This 0V command signal then flows to the analog switch switching circuit 23, and the signal from the Hall element 19 is transmitted to the analog switch switching circuit 23.
Confirm that it is ON and turn the analog switch 21
Switch from b to a. and controller 22
A command signal of 0V is applied to the motor 11, and a voltage proportional to the command signal from the opening/closing control signal generator 24 of the rotary tap 10 is applied to the motor 11, and the motor 11 is operated at the maximum rotation speed in the left direction, changing the rotary tap 10 from the open state to the closed state. When the output of the Hall element 18 reaches a certain voltage level, the analog switch switching circuit 23 switches the analog switch 21 from a to b to stop the motor 11 and close the rotary tap 10.

The signal from the signal converter 20 is called Signal R, the signal from the Hall element 18 is called Signal A, and the signal from the Hall element 19 is called Signal B. As shown in the figure, time T is plotted on the horizontal axis, and the input signals and the operating states of the motor 11 and the rotary stopper 10 are shown in FIG.

〔Effect of the invention〕

As explained above, according to the control method of the mud pulse generator of the present invention, the rotary plug for opening and closing the bypass passage is driven by a motor, and the state of the cutter bit detected by the instrument part and the bottom of the mine are controlled. Since the rotation of the motor is controlled by feeding back the opening/closing status of the rotary stopper based on data such as the status of In addition to being able to control the opening and closing of the rotary tap extremely easily while taking advantage of the have

[Brief explanation of drawings]

1 to 8 show an embodiment of a control system for a mud pulse generator according to the present invention, in which FIG. Figure A is a sectional view of the rotary stopper, Figure 2-B is a front view thereof, Figure 2-C is a plan view, Figures 3-A and 3-B are explanatory diagrams of the open and closed states of the rotary stopper, Figure 4 a, b, c and Figure 5 a, b,
c is a conceptual diagram of the rotating body, Fig. 6 is a control system diagram, and Fig. 7 is a conceptual diagram of the rotating body.
The figure is a diagram of the operational relationship between the rotary stopper and the analog switch, FIG. 8 is an explanatory diagram of the operating state of the input signal, motor, and rotary stopper, FIG. 9 is an explanatory diagram of a conventional mud pulse generator, and FIG. is an explanatory diagram of the relationship between the pressure of the muddy water Mh and time. DESCRIPTION OF SYMBOLS 1...Bedrock, 2...Drill pipe, 3...Bit, 4...Casing, 5...Instrument section, 6...Inside mine, 7...Muddy water bypass passage, 8...Solenoid, 9...Piston valve, 10...Rotating stopper, 1
1...DC servo motor, 12...Communication hole, 13
...Axis, 14...Rotating body, 15...Box, 16,
17... Magnet, 18, 19... Hall element, 20... Signal converter, 21... Analog switch, 22... Controller, 23... Analog switch switching circuit.

Claims (1)

[Claims] 1. A drill pipe equipped with a cutter bit for drilling is provided with a casing housing an instrument section for detecting the state of the cutter bit and the condition of the bottom of the pit excavated by the cutter bit, and the casing and the drill pipe are A mud pulse generator is provided with a bypass passage that allows a part of the muddy water pumped toward the cutter bit to escape to the outside of the drill pipe, and a rotary stopper that opens and closes the bypass passage; A driving motor, a sensor that detects the open/closed state of this rotary stopper, and a switch switching circuit that generates an ON-OFF signal according to the detection signal of this sensor are provided, and the data detected by the instrument section is provided. a signal generator that generates a data signal in accordance with the data signal; a signal converter that generates an ON-OFF signal by comparing the data signal with a predetermined reference value;
ON-OFF output from the switch switching circuit
Signal and ON-OFF output from the signal converter
and a switch for inputting an ON-OFF signal of the signal converter or a stop signal based on the reference value to a controller that controls the rotation of the motor. control method for the generator.