SU805228A1 - Device for well electro-logging - Google Patents

Description

(54) DEVICE FOR WELLS OF NOY ELECTRICAL EXPLORATION.

I

The invention relates to well logging and can be used to study the amplitude and phase characteristics of magnetic fields.

A device for measuring complex magnetic field components transverse to the well axis is known, comprising a housing for a downhole tool, a signal generator, a frame for receiving a variable electro magnetic floor, an eccentric weight associated with the frame for spatially positioning the frame and an active and reactive meter. received frame signal 1.

 in a device for measuring a transverse magnetic field, by alternately measuring two orthogonal (vertical On) and horizontal Hp) spatial KOMnoHeHf with a frame oriented in space by an eccentric weight, with the subsequent recalculation of the measured values into the module value and the angle of inclination of the transverse vector magnetic field In order to ensure free rotation of the frame between the inner wall of the casing of the downhole tool and the frame, it is necessary to have a guaranteed gap, which does not allow to fully use the internal volume of the housing to accommodate the frame. This leads to a decrease in the sensitivity of the device. 5 In addition, the casing of the borehole rib must have sufficient wall thickness to prevent their deformation under the influence of hydrostatic pressure from the water supply or drilling fluid that fills the wells. The possibilities of increasing the sensitivity of the body of the receiving frame by increasing the longitudinal dimensions are also limited by the required accuracy of self-weighting and the maximum allowable weight of frames. With a small diameter of € zhvazhv my device and a small deviation of sv | izhny from

The vertical rotation of the Mayvit eccentric weight in the known device is not sufficient to rotate the framework. For this reason, jamming of the rotating frame often occurs, which reduces the quality of the frame.

accuracy of measurements.

In order to ensure a small moment of friction, the supports of the movable part should have a small area, due to which there can be failures in the operation when the instrument strikes the walls

wells during tripping. The signal from the rotating frame to the input of the meter in this device is transmitted through a collector current collector, which further reduces the reliability of the device and the accuracy of self-weighting.

It is also known a device for measuring a magnetic field transverse to the axis of a well during electrical prospecting, comprising a well and a surface part. The borehole part consists of a casing of the downhole tool, fixed in the casing of the receiving frames for receiving orthogonal magnetic field components and a sensor for the angle of rotation of the frames relative to the vertical plane of curvature of the borehole axis. The steering angle sensor contains an eccentric weight and a phase shifter consisting of a fixed part (stator) and a rotating part (rotor) rigidly connected to the eccentric weight. The ground equipment consists of active and reactive signal components; containing input signal converters and meters, generator and phase meter. The generator is connected to the input of the phase shifter and one of the inputs of the phase meter. The second input of the phase meter is connected to the output of the phase shifter 2 ..

This device allows the measurement of two arbitrarily oriented mutually orthogonal components on the 1st magnetic field and the angle of rotation of the downhole tool relative to the vertical plane of curvature of the axis of the well. This device cannot directly measure the components of the Nwi Hp transverse magnetic field and the modulus and angle of inclination of the transverse magnetic field vector to the vertical plane of curvature of the borehole axis in field conditions. Since the receiving frames, when the downhole tool moves along the well, have an arbitrary receiving direction at the time of measurement, it is necessary to make calculations using the measured values of the orithogonal components of the magnetic field and the angle of rotation of the frames relative to the vertical plane of curvature of the well axis, which reduces The availability of information and productivity.

The purpose of the invention is to increase productivity.

 This goal is achieved in that a device for borehole electrical prospecting, comprising a downhole tool, in the case of which two orthogonal receiving frames are fixed and a sensor for the angle of rotation of the frame plane relative to the vertical plane of curvature of the borehole axis is mounted, including input transducers connected to the receiving frames Signals,; 1 measuring instruments in a generator connected to the input of the angle and rotation sensor, between the input signal converters and measuring devices and a coordinate conversion circuit is included, the control inputs of which are connected respectively to the outputs of the generator and the angle sensor, the coordinate conversion circuit contains two modulators at the input, the signal outputs of which through filters are connected to the inputs of the signal adder, and the control input of one modulator directly connected to the output of the generator, and the other through an orthogonal phase shifter, the output of the adder is coupled with two parallel circuits, each of which will be connected in series a phase detector and a low pass filter, wherein the control inputs of phase detectors coupled to the output angle sensor such that one phase detector connected to the output date. The angle of rotation through the graduated phase shifter, and the other through the graduated and orthogonal phase shifters. The drawing shows a diagram of the proposed device. .

5 The device contains in the borehole part the housing 1 of the downhole tool, fixed in the case receiving frames 2 for receiving orthogonal components of the magnetic field, sensor 3 of the angle of rotation of the frames relative to the vertical plane of the borehole axis, containing an eccentric load 4 and a phase shifter consisting of a fixed part ( stator) 5 and rotating part (rotor) 6, rigidly connected with eccentric weight 4. The ground part consists of input transducers 7, coordinate conversion circuit 8 having two signal and two control inputs and two outputs containing modulators 9 signals, adder 10, filters 11, phase detectors 12, the outputs of which through 13 low-pass filters are connected to measuring instruments 14. Control inputs of modulators are connected to the output of generator 15, with one input connected directly, and the second through an orthogonal phase shifter 16. The balancing inputs of the phase detectors 12 are connected to the output of the rotation angle sensor 3,. moreover, one is connected via a graduated phase shifter 17, and the second through a graduated and orthogonal phase shifter 16.

Received arbitrarily oriented jibJMM receiving frame 2 orthogonal

Composite signals, proportional to the corresponding transverse magnetic field, are amplified and converted into direct current signals by input transducers 7. Their output signals are converted into non-temporal current signals by modulators 8. The control of the modulators is derived from the generator 15 signals, and the control signal for one of the modulators is shifted in phase by 90 ° by the orthogonal phase shifter 16. From the output signals of the modulators, filters 1 i separate the first MONICA heaps of signals and the post fall on the input of the adder 10. Since the difference between the input signals of the adder is 90 °, the signal at its output is proportional to the geometric sum of the input signals, i.e., the module of the transverse magnetic field. The signal received at the output of the adder is again decomposed into orthogonal components, but already in an oriented coordinate system. The output signals of the phase detectors 12 after suppressing the high-frequency components of the 13 LOWER frequency filters are measured with measuring devices 14. The control signal for the phase detectors is removed from the output of the phase rotation sensor of the angle of rotation 3, passes through the graduated phase shifter 17, and the control signal of one of the phase detectors passes through is shifted in phase by 90 ° by the orthogonal phase shifter 16. As the downhole tool rotates around the longitudinal axis, the rotation angle sensor rotor retains eccentric weight in a stationary position relative to the vertical plane of the borehole axis, the stator 5 of the phase rotator rotates together with the casing of the downhole tool 1. Due to the relative rotation of the rotor 6 and the stator 5 of the phase rotator, the phase increment of the signal changes at the sensor output angle of rotation relative to the phase of the input signal. Since at. the rotation of the downhole tool around the longitudinal axis at an angle. Dt at the same angle changes the phase of the output signal of the adder and phase of the control signals of the phase detectors: 12, the voltage at the outputs of the phase detectors are invariant with respect to the rotation of the downhole tool around the axis, i.e. the measurement of the orthogonal components of the transverse magnetic field by the meters 14 will be performed in the coordinate system fixed relative to the vertical plane, it is scrolled; well axis.

To measure the module and the angle of inclination of the transverse magnetic field vectors, the graduated phase shifter shifts the phase of the reference signal until the readings of one of the signals are equal to zero. measuring devices 14. The readings of the second measuring device 14 will be proportional to the module of the transverse magnetic field, and the angle of inclination of the vector to the vertical plane of curvature of the borehole axis is measured by the graduated phase sensor.

Direct measurement of two orthogonal components of the magnetic field or module transverse to the borehole axis and the angle of inclination of the transverse magnetic field vector to the vertical plane of curvature of the borehole axis eliminates the need for additional calculations, increases labor productivity and information accuracy. A device for measuring the transverse to the borehole axis magnetic field is included in the Lazurit electrical survey geophysical instrumentation kit, designed for measurements both in the boreholes and from the surface.

15

Claims (2)

Invention Formula A device for downhole electrical prospecting, containing a downhole tool, in the case of which two orthogonal receiving frames are rigidly fixed; a sensor for the angle of rotation of the plane of the frames relative to the vertical plane of curvature of the borehole axis is placed; The frames are input signal converters, measuring devices and a generator connected to the input of a rotation angle sensor, characterized in that. in order to increase labor productivity, a coordinate conversion circuit is included between the input transducers of the sigals and the measuring instruments, the control inputs of which are connected respectively to the output of the generator and the output of the angle-of-rotation sensor, 2. The device according to claim 1, characterized by By the fact that the coordinate transformation system contains two modulators at the input, the signal outputs of which are connected via filters to the inputs of the signal combiner, and the control input of one modulator connected to the generator output directly, and the other through the orthogonal phase shifter, the output of the adder is loaded with two parallel circuits, each of which contains a phase-connected phase detector and a lower filter frequencies, and the control inputs of the phase detectors are connected to the output of the angle sensor in such a way that one phase detector is connected to the output of the angle angle sensor through the variable phase shifter and the second through the graduated and orthogonal phase shifters. Sources of information taken into account in the examination 1.Sb. “Well and ore geophysics. L., “Nedra, 1971, p. 121 - 129. 2. USSR author's certificate According to the application number 2608028, class; G 01 V 3/08, 1978 (prototype).