JPS6374223A - Underground communication equipment - Google Patents

Abstract

PURPOSE:To improve the reception sensitivity on ground and the S/N by separating a conductor such as a drill pipe or the like whose part is connected to ground into two parts insulated electrically by an insulation layer and using the ground as a part of the electric circuit to constitute a closed circuit thereby sending a signal from the underground while using a change in the electric field as a medium. CONSTITUTION:A drill string is constituted by connecting lots of drill pipes 4. A drill pipe 40 at the tip accommodating a layer checking measuring instrument 80 and a transmission section 90 is separated by an insulation collar 6 while being insulated electrically into a bottom 41 and an upper part 42. Moreover, a lead is connected respectively to the bottom 41 and the upper part 42 of the drill pipe 40 at the tip from the transmission section 90 and the bottom 41 is grounded via a bit 5 digging the ground layer 2. Other other hand, an amplifier 11 constituting a reception section and a proper signal processor or the like constituting a reception section are provided to the ground side. One input terminal of the amplifier 11 is connected to the drill pipe 4 at the uppermost part and the other input terminal is connected to ground, that is, the ground layer 2, and its output is given to the signal processor.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to, for example, a measuring device for well logging, a taper for drilling oil or natural gas, etc., i.e., when drilling oil wells, gas wells, etc. , a device attached to the tip of a drill pipe to measure the properties of the bottom of a hole, or other various measurement devices buried underground, to the ground ring, or to transmit signals from the ground to those devices. relating to underground communication equipment.

[Prior art]

For example, conventionally, when drilling a vertical shaft such as an oil well for oil drilling, in order to obtain various information about the geology near the bottom of the pit or the drilling bit, the drill pipe was first raised above the ground and inspected, or well logging was performed. Either by lowering a measuring device into the shaft to take measurements, or by mud logging, which analyzes the state and components of the mud that circulates upward in the shaft from the top of the drill pipe through the tip of the bit during drilling. logging)
A method called ``is used.

However, each of the above-mentioned methods requires a relatively long time to measure;
Furthermore, it was difficult to measure the bottom of the hole in real time during excavation. Due to these circumstances, in recent years MWD
(Measurement While Drilli
A method called ng) has been developed. Simply put, this MWD is achieved by attaching a well logging measurement device equipped with a sensor to the tip of a drill pipe near the bottom, and transmitting the various data obtained to the ground via electromagnetic waves, etc. The purpose is to measure the properties of the bottom of the pit (including the state of the bit) in real time and obtain that data.

As an example, Figure 3 shows OGJ Report Feb.
21. In 1983 “5econd-Generation”
n MWOTool Pa5ses FieldTes
In the schematic diagram showing the configuration of the device announced under the title "t",
1 is a drilling rig, 2 is a geological layer, 3 is a vertical shaft being drilled, that is, an oil well, and 4 is a drill pipe that is rotated by a power source (not shown) and transmits the power to the bit 5. Accordingly, a large number of drill strings are connected together to form a drill string.

5 is a pin for drilling the stratum as described above, and 6 is an insulating collar that divides the drill pipe 40 directly above the bit 5 into a bottom portion 41 and an upper portion 42 and electrically insulates the two. It is.

Further, in the figure, a range 7 surrounded by a broken line indicates a dipole antenna formed by the bottom 41 and the top 42 of the most advanced drill pipe 40 and the drill pipe 4 and the insulating collar 6 at a position higher than that. . 8 is a containment vessel attached to the inner cavity of the bottom part 41 (11) of the most advanced drill pipe 40.

This containment vessel 8 houses a well logging measuring device 80 and a transmitting unit 90 of a communication device for transmitting data obtained by the well logging measuring device 80 to the ground ring.

The well logging measurement device 80 measures various properties, such as temperature, regarding the bottom of the oil well 3 and the bit 5 during drilling.

It consists of sensors that measure pressure, vibration per rotation torque, etc. In addition, the transmitter 90 of the communication device modulates and amplifies the data obtained by the logging measurement device 80 and transmits an electric signal from the above-mentioned dipole antenna 7 as shown by the dotted line.
It is composed of a transmitting circuit and the like for outputting as i-waves.

On the other hand, on the ground is an antenna 1 that constitutes a receiving section of a communication device.
0. Amplifier 11. A signal processing section 12 and the like are provided.

Specifically, a linear antenna 10 is extended approximately centered on the oil well 3, and electromagnetic waves received by this antenna 10 are output to an amplifier 11.

This amplifier 11 amplifies the signal given from the antenna 10 and outputs it to the signal processing section 12. The signal processing unit 12
The output signal of the amplifier 11 is demodulated to reproduce data on the bottom of the pit, that is, data measured by the well logging measurement device 80 housed in the containment vessel s.

FIG. 4 is an enlarged vertical cross-sectional view of the dipole antenna 7 described above.
Conductive wires C1 and C2 are connected to the bottom 41 and top 42, respectively, which are electrically insulated by the dipole antenna 7.
is configured.

Such conventional devices operate as follows.

Drill pipes 4, 4... to which many drilling rigs 1 are connected.
When the drill string consisting of the drill string is rotated, the bit 5 attached to the tip of the most advanced drill pipe 40 also rotates, so the bit 5 excavates the stratum 2 at the bottom of the oil well 3. At this time, the bottom 4 of the most advanced drill pipe 40
A measuring device 80 for well logging in a containment vessel 8 attached to a sensor 1 measures the properties of the stratum 2 at the bottom of the well or the state of the bit 5, and the data obtained as a result is modulated and transmitted by a transmitter 90. The signal is amplified and applied as an AC signal of 5 to 6011 z to a dipole antenna 7 which electrically insulates the drill pipe 4 with an insulating collar 6. As a result, electromagnetic waves are radiated from the dipole antenna 7 as shown by dotted lines in the figure.

Note that the frequency applied to the dipole antenna 7 is 60
In the case of 11z, it is 5000 km when converted to the wavelength in the air.
The wavelength becomes extremely long.

On the ground, on the other hand, the electromagnetic waves radiated from the dipole antenna 7 and propagated through the stratum 2 are received by the linear antenna 10, amplified by the amplifier 11, and then sent to the signal processing unit 12.
It is played back as data.

[Problem that the invention seeks to solve]

By the way, in the conventional communication device having the above-mentioned configuration, from the viewpoint of underground communication, an extremely long wavelength electric current M'6Jt is used as a data transmission medium, so a highly efficient A
It is difficult to obtain wavelength transmitting and receiving antennas, so the S/N of the received signal is extremely low, thus making it difficult to accurately transmit data.

Furthermore, if a geological formation with a high water content is present during the propagation of electromagnetic waves, the electromagnetic waves will be significantly attenuated, causing problems such as a further decrease in S/N. This is even more noticeable when muddy water is present around the drill string.

The present invention was made in view of these circumstances, and
By using electric fields instead of electromagnetic waves as the medium for data transmission, in other words, by constructing an electric circuit between the drill pipe and the ground and transmitting electric signals through this circuit, data can be transmitted with high S/N. The purpose is to provide underground communication equipment.

[Means for solving problems]

The underground communication device of the present invention consists of a conductor such as a drill pipe, a part of which is grounded to the earth, and two parts electrically insulated by an insulating layer, specifically, a part that is grounded to the earth, and the other. By separating the two parts and connecting the transmitter (or receiver) to these two parts, and connecting the receiver (or transmitter) to the ground of the conductor and the ungrounded part to the ground. An electric circuit is configured, and an electric signal is transmitted through this electric circuit.

[Effect]

The underground communication device of the present invention includes an electric circuit that includes the earth as a part, and a signal to be transmitted is propagated through this circuit using an electric field as a medium.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.

FIG. 1 is a schematic diagram showing the configuration of an underground communication device according to the present invention. Note that the same reference numerals are given to the same constituent members or corresponding members as in the explanatory diagram of the conventional example described above.

Numeral 4 in the figure is a drill pipe, and a large number of drill pipes are connected to form a drill string as in the prior art described above, and a bit 5 attached to the tip of the most advanced drill pipe 40 is used to drill vertically into the stratum 2. Oil well 3, which is a pit, is being drilled.

In the present invention, for example, the transmitter 90 and the logging measurement device 80 of the device of the present invention are attached to the drill pipe 40 directly above the bit 5, and an equivalent circuit as shown in FIG. 2 is formed. be done.

In the underground communication device of the present invention, as in the conventional device described above, the cutting-edge drill pipe 4o in which the logging measurement device 80 and the transmitter 90 of the device of the present invention are housed is connected to the bottom portion 41 and the upper portion by an insulating collar 6. It is electrically insulated and separated from 42.

In addition, the transmitter 90 is connected to the bottom 41 and top 42 of the most advanced drill pipe 40 with conductive wires, respectively.
Furthermore, it goes without saying that the bit 5 that excavates the stratum 2 is in contact with the stratum 2, that is, electrically coupled, more specifically, grounded.

On the ground side, on the other hand, there are provided an amplifier 11 and a suitable signal processing device, etc., which constitute the receiving section of the device of the present invention. Specifically, the amplifier 11 is provided with one input terminal connected to the drill pipe 4 at the uppermost end and the other input terminal connected to the ground, that is, to the stratum 2. The output is given to an appropriate signal processing device as in the conventional device described above.

Therefore, in the device of the present invention, the transmitter 9o is connected to the stratum 2 through the bottom 41 of the most advanced drill pipe 40, and the transmitter 9o is further connected to the uppermost part 42 of the most advanced drill pipe 4o from the uppermost drill pipe 4 via the amplifier 11. A closed circuit, that is, an electric circuit of an equivalent circuit as shown in FIG. 2 is formed through the main body 90.

In the device of the present invention, the signal representing the data obtained by the well logging measuring device 8o is transmitted as an electrical signal by the transmitter 9o.
In other words, it appears as a change in the electric field.

Now, the operation of the underground communication device of the present invention configured as described above is as follows.

For example, a measurement signal from a sensor (not shown) is converted into a digital quantity by the well logging measurement device 8o, and further converted into a binary numerical value string. Based on this numerical value sequence, the transmitter 9o of the device of the present invention uses its transmitter circuit to phase-modulate, for example, a sine wave, amplify it, and output it. This signal is transmitted to a plurality of drill pipes 4, 4, . . . from the uppermost drill pipe 4o.
One terminal is connected to the transmitting section 90 via the upper part 42 of the most advanced drill pipe 40 through a drill string composed of
Also, the formation 2 and the bottom 4 of the cutting edge drill vibe 40
The other terminal is applied to the amplifier 11 connected to the transmitting section 90 via the transmitter 1 .

Therefore, the electrical signal output from the transmitter 90 is propagated to the amplifier 42 as a change in the electric field and amplified there, so if the output of the amplifier 11 is processed appropriately, the well logging measuring device 80 This means that various data measured at the bottom of the oil well 3, ie, underground, are transmitted to the ground.

In the above embodiments, an example of equipment for excavating vertical shafts for drilling oil wells, gas wells, etc. was shown. It can also be used as equipment for transmitting data from buried seismometers, etc.

Further, in the above embodiment, an example is explained in which a signal is transmitted from the underground side to the ground side, but it goes without saying that signal transmission from the ground side to the underground side or in both directions is also possible.

〔effect〕

As described above, according to the present invention, a closed circuit is constructed using the earth as part of the electric circuit, and signals are transmitted from underground using changes in the electric field as a medium through this circuit. Compared to conventional devices that use radio waves generated by an antenna with an insulating collar as a medium, the receiving sensitivity on the ground is higher and the S/N ratio is also improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an underground communication device of the present invention, FIG. 2 is an equivalent circuit diagram thereof, and FIGS. 3 and 4 are explanatory diagrams of prior art. 2...Geological formation 3...Oil well 4...Drill pipe 5...Bit 6...Color line color 11.
...Amplifier 40...The most advanced drill pipe 41.
... Bottom of the most advanced drill pipe 42 ... Upper part of the most advanced drill pipe Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] 1. An underground communication device for transmitting a signal from one end of a conductor to the other end of a conductor located in an underground cavity, a part of which is grounded within the cavity, The conductor is electrically separated into a first part including a grounding part and a second part by an insulating layer, and a transmitter (or receiver) is separated between the first part and the second part. connect the receiver (or transmitter) to the second
An underground communication device characterized by being connected to the ground and the ground. 2. The underground communication device according to claim 1, wherein the conductor is a drill pipe for excavating the earth.