SU947408A1 - Azimuth converter - Google Patents

Description

The invention relates to geophysical studies of wells and can be used to determine the magnetic azimuth of boreholes using a single conductor wire.

Known inclinometer containing a generator, frequency doubler, cable length sensor, RC phase shifter, selective amplifier, two Schmitt triggers, phase-time converter, interval, counter, logging cable, orthogonal flux probes, two switches, two amplifiers, frequency divider and sinus cosine transformer TS.

A disadvantage of the known device is a small amount of information per each information channel. For example, two information channels (two cable cores) are required to transmit information from each inclinometer sensor.

The closest to the present invention is a fluxgate azimuth sensor containing a cable length sensor, a phase shifter, two identical conversion channels consisting of a generator, a selective amplifier, a phase detector, a frequency doubler, a modulator, and a reference voltage generator two Ymitt triggers, phase-time interval converter, counter, logging cable, two orthogonal ferrosonde.

The disadvantages of the described device are the presence of a two-wire information kangsh connection between

10 downhole tool and surface control, which requires the use of a three-core logging cable and a magnification. The cost of work on the study of drilling wells, as well as a significant 15 for the error arising from the non-identical parameters of the conversion channels and inaccurate phase adjustment of the doublers by the phase shifter according to the cable length sensor signals. Besides

20 addition, the ground control of the known device has a complex structure.

The purpose of the invention is to improve the measurement accuracy by eliminating the influence of logging cable parameters.

25 to the final measurement result and simplify the design of the electronic part.

This goal is achieved by the fact that a device comprising a generator, a frequency doubler, a selective

30 silicon, phase detector, two modulators, RC phase shifter, two three Schmitt heras, phase-to-time converter, meter, carot cable, two orthogonal ferrods, two switches and memory sticks, and one switch is inserted between orthogonal ferrosonde and cable and the other is connected to the generator and the memory unit, which is connected between the output of the phase detector and the inputs of the modulators. The drawing shows a functional diagram of the azimuth converter. The azimuth converter contains a generator 1, a frequency doubler 2 connected to a generator 1, a selective amplifier 3, a phase detector 4 connected to a frequency double 2 often and a selective amplifier 3, a memory block 5, a switch b connected to generator 1 and memory block 5, two modulators 7 and 8, connected by inputs to generator 1 and memory block 5, and outputs to a HC-phase shifter 9, Schmitt triggers 10 and 11 are connected by inputs to generator 1 and PC-. phase shifter 9, and outputs - to convert Tieliu 12 and phase-timeslot, the output of which is connected to a counter 13, a wireline 14, a switch 15 connected between the cable 14 and ferroprobes 16 and 17. The converter operates as follows azimuth. The generator 1 produces a sinusoidal voltage that is fed through the cable 14 to the downhole tool. The amplitude of the output voltage of the generator 1 varies at time intervals set by the switch 6. The switch 15, located in the well device, is controlled by the voltage supplied from the generator 1, and alternately connects the flux probes 16 and 17 to the cable 14, i.e. alternately applies the excitation voltage to the flux-gates. Thus, the voltage of the generator 1 serves to excite the flux-probes 16 and 17 and simultaneously controls the switch 15. Due to the fact that the flux-probes are arranged orthogonally, in their windings when the excitation voltage is applied and under the influence of the horizontal component of the Earth’s magnetic field, ts emf of the second harmonic (with respect to the frequency of the generator 1), proportional in amplitude to the sine and the coarseness of su azimuth. The information EMF of the second harmonic is supplied via cable 14 to the input of the selective amplifier 3 tuned to the appropriate frequency of the information EMF. Phase detector 4, the reference voltage for which is taken from frequency doubler 2, conducts a phase-sensitive rectification of the output signal of the selective amplifier 3. The constant voltage from the output of phase detector 4 is fed to the input of memory block 5, which captures the instantaneous value of the output voltage phase detector 4 for a certain time on the gate pulses coming from the switch 6, and the gate pulses have a delay relative to the pulses that drive the generator 1 for the time required End of cable transients. Thus, the memory unit fixes the DC voltages, the amplitudes of which are proportional to the sine and cosine of the azimuth, and the continuous supply of these voltages to the inputs of the modulators 7 and 8, the latter transform the DC voltages into variables. From the outputs of voltage modulators 7 and 8, proportional in amplitude to the sine and cosine of the azimuth, are applied to a KS phase shifter 9 tuned to the frequency of the oscillator 1. The phase of the output voltage of the RC phase shifter 9 is proportional to the azimuth. The voltages from the generator 1 and the RC phase shifter are fed to the inputs of the Imitt trigger 10 and 11, which form a series of square pulses, the phase shift between which is proportional to the azimuth. The transducer 12 phase-time interval forms a sequence of pulses with a duration proportional to the azimuth. The output signal of the converter 12 is fed to a counter 13, from which information in a digital form is taken about the azimuth of the well. The proposed azimuth converter differs from the known devices in that it allows the measurement of azimuth using a single core wire, due to the fact that the flux probes are alternately connected to the cable using a switch 15 controlled by the generator voltage amplitude .1. The device has great accuracy, because, due to the alternate connection of the flux-probes fed by the voltage of one frequency, the parameters of the latter do not affect the final measurement result, which makes it possible to exclude the cable length sensor and phase shifter from the circuit. In addition, there is no systematic error in the conversion of information signals of flux-probes, since the signal flux of each flux-probes is performed by the same elements: a selective ycv file and a phase detector. PreobraoDDte scheme

Claims (1)

Claim An azimuth converter containing a generator, a frequency doubler, a selective amplifier, a phase detector, two modulators, a PC phase shifter connected to the modulator outputs, two Schmitt triggers connected in series with the phase-time interval converter and with a counter, two orthogonal flux gates, a wireline cable, characterized in that, 5 in order to improve the measurement accuracy by reducing the influence of the parameters of the logging cable, it is equipped with two switches and a memory unit, while one of the switches is connected between orthogonal flux gates and connected via a cable to a selective amplifier, and the other switch is connected to a generator and to a memory block , the input of which 15 is connected to a phase detector, and the output of the memory unit is connected to the modulator.