SU1550455A1 - Electric prospecting station - Google Patents

Abstract

The invention relates to geophysics, namely, geoelectromagnetic, and is intended for use in the exploration of oil and gas fields by sounding methods by field formation and magnetotelluric sounding. The purpose of the invention is to increase the information content by expanding the frequency and dynamic ranges of measurement. The electrical survey station contains measurement channels connected to a series-connected channel switch, a pulse analog-to-digital converter, an arithmetic logic unit and a magnetic recorder, and also contains a memory device and a control system connected to the arithmetic logic unit. Each measuring channel contains in series a sensor of a magnetic or electric component, a field, an amplifier and a switch, to the second input of which a digital-to-analog converter is connected. The control inputs of the D / A converter, the switch, the channel switch, the pulse analog-digital converter and the magnetic recorder are connected to the control system. In addition, each measuring channel additionally contains a second digital-to-analog converter, a differential amplifier, and a second switch. The digital inputs of two digital-to-analog converters are connected to the auxiliary output of the arithmetic logic unit, the control inputs of the second switch and the second digital-to-analog converter are connected to the control system. The inputs of the differential amplifier are connected to the outputs of the first switch and the second digital-to-analog converter. The inputs of the second switch are connected to the outputs of the amplifier and the differential amplifier, and the output of the second switch is connected to the input of the channel switch. The second D / A converter allows the signal code at the station input to be converted into a second level compensation signal in each encoding interval. The second switch provides the amplified differential signal of the differential amplifier to the analog-to-digital converter. The compensation signal for each individual coding cycle is independent of the size of the compensation signal for the previous coding. 1 il.

Description

The invention relates to geo-Physics, and more specifically to geoelectroprospecting, and is intended for use in the exploration of oil and gas fields using field sounding and magnetotelluric sounding methods.

The invention is aimed at increasing the information content by expanding the frequency and dynamic ranges of measurement.

The drawing shows a block diagram of the proposed device. The device contains a number of measuring channels containing in series a sensor 1 of a magnetic or electric field and an amplifier 2, and also containing a first digital-to-analog converter (PAL) 3, a first switch 4, a second PAP 5, a differential amplifier 6, a second switch 7.

Measuring channels are connected to a switch of 8 channels, the output of which is connected to an analog-digital converter (A1Sh) 9 connected in series, an arithmetic logic unit (ALU) 10, a magnetic recorder 11.

The device also contains a storage device (memory) 12 and the control system 13, the measuring channels in the drawing are shown by a dotted line.

The device works as follows.

In each measuring channel, sensor 1 converts the field components into electrical signals, which are amplified by amplifier 2 and, after a series of conversions, arrive at the switch of 8 channels, which in turn feeds signals from the measuring channels to the ADC 9. Signal codes arrive at ALU 10 for preliminary processing and then do & a magnetic recorder 11 for recording onto a magnetic tape. The operation of the device is controlled by the control system 13.

The control system 13 consists of a crystal oscillator and a multi-phase clock distributor connected to it with n clock outputs. The control system is a well-known standard digital device, made, for example, on complementary integrated circuits.

0

five

0

five

0

five

0

five

At the clock outputs of the control system 13, there are sequences of clock pulses that determine the trigger points of the station nodes. At the output of the clock interval number, a parallel code of the clock interval number in the work cycle of the station is used, according to which the ALU 10 selects the work subprogram for the given interval. The overall measurement limit of the field is given by the transfer coefficients of sensor 1 and amplifier 2. The range of output signals of NAL 3 and 5 is equal to the range of input signals of the ASH 9, the number of binary bits of the AMC is equal to t, the number of binary bits of the AO is equal to n. Switches 4 and 7 are set to the position when signal A from the output of amplifier 2 is fed to differential amplifier 6 and switch 8. APC 9 finds the code N (A) of the signal AI and the ALU 10 from code M (A) extracts the code M (A) n senior bits The ALU 10 writes the code M (A) to the memory 12 and the auxiliary output supplies the code M (A) to the first PAP 3. The arithmetic logic unit of the ALU 10 is made in the form of a typical microprocessor device (Electronik-60 microcomputer, for example). All the ALU 1 O controllers, through which the ALU 10 exchanges data and commands with other nodes of the station, are identical and connected to the common bus ALU 1 0 and implement the standard interface. The second Sh. P 5 converts the code M (A) into the compensation signal B. Differential amplifier 6 subtracts the compensation signal VM from the signal A and amplifies the difference signal. Then the second switch 7 changes its state and the amplified difference signal C

  (A. - Wm), after which the ASH 9 finds the N (C) code of this signal and feeds it to the ALU 10, which calls from

The memory code AND (A) and using it as the address, calls from memory 12 the previously recorded code K (VM) of the compensation signal VM. Then the ALU I0 finds the code of the signal A in the form of K (A) K (BW) + N (C). From the ALU 10, the code K (A) enters a magnetic recorder 11 for recording on a magnetic tape. This completes the single encoding cycle. At the specified interval, the following coding will be performed.

In the intervals between coding of signal A, coding of compensation signals B is made and the K (VM) codes of these signals are written into memory 12.

The introduction of a second digital-to-analog converter 5 into the measuring channel of an electrical survey station allows the signal code at the station input to be converted into a second level compensation signal simultaneously with the first digital-analog converter 3 converting the input signal code into an auxiliary signal. This operation is performed at each interval. The introduction of the second switch 7 into the measurement channel of the station allows the amplified difference signal, which is formed when the deLoperational amplifier 6 is subtracted from the output signal of the amplifier 2 of the compensation signal, fed to the ADC 9. The compensation signal for each individual coding is independent of the compensation signal for the previous coding. At the same time, the differential nonlinearity of the amplitude characteristic of the measuring channel does not exceed the unit of the least significant bit ASCH 9.

Claims (1)

Invention Formula / An electrical survey station containing measuring channels connected to a series-connected channel switch, analog-to-digital converter, arithmetic logic unit, and magnetic recorder, containing a memory device and control system five 0 five 0 five 0 nor, connected to the arithmetic logic unit, with this k, ch ly The measuring channel contains a series-connected sensor of a magnetic or electrical component of the electromagnetic field, an amplifier and a switch with two inputs, to the second input of which the first electronic analog converter is connected, and the control inputs of the analog converter, switch, channel switch, analog-digital converter and magnetic recorder are connected to the clock control system outputs, characterized in that, in order to increase the information content by expanding the frequency and Measuring measuring ranges, each measuring channel additionally contains a second digital-to-analog converter, a differential amplifier and a second switch with two inputs, the digital inputs of the first and second pi-analog converters are connected to the output setting of the initial code of the arithmetic logic unit, the control inputs of the second switch and the second digital-analog converter are connected to the clock outputs of the control system, inputs,. the differential amplifier is connected to the output of the first switch and the output of the second D / A converter, the inputs of the second switch are connected to the output of the amplifier and the output of the differential amplifier, and the output of the second switch is connected to the input of the corresponding channel of the 1-channel switch.