SU972435A1 - Seismic signal recording method - Google Patents

Description

(54) METHOD OF RECORDING SEISMIC SIGNALS

one

The invention relates to seismic exploration and is intended to visualize seismic signals.

A known method of recording seismic signals, according to which, along with recording, the methods of variable deviations, density, width, and a combination of density with a deviation, realize combinational recordings of variable width with density and variable width with deviation. In this method, an image is formed by highlighting in the form of dots or strokes, depending on the type of image of seismic signals, areas of horizontal movement of the light beam (recording element) along the recording medium. The recording process is controlled by two channels 1.

The disadvantage of this method is that the image is discrete, i.e. consisting of a set of dots. This is especially noticeable on the steep edges of the recorded signals, which negatively affects the quality of the recording and interpretation. In addition, there is an overhead on moving the recording element, since

its movement sawtooth signal, which causes a decrease in the speed of recording information. However, the use of a sawtooth signal ensures the uniformity of the speed of the recording element on the record carrier and the constancy of the exposure time.

The closest technical solution to the present invention is a method of recording seismic vibrations, according to which the recorded signal is divided into two

 in the first channel, the recorded seismic signal is converted into a voltage corresponding to one of the types of recording: the amplitude is variable, the width is variable. Then the voltage received

, 5 in the first channel, controls the movement of the recording element on the record carrier. In the second channel, depending on the type of recording, the original signal is either converted into square pulses or left unchanged. Second signals

The 20 channels control the intensity of the effect of the recording element as it moves along the carrier 2.

The disadvantage of this recording method is the change in the exposure on the photosensitive recording medium depending on the speed of movement of the recording element, i.e. the uneven speed of movement of the recording element over the recording medium. At the fronts, it is maximum, and at the vertices, it is minimal, as it controls the movement of the recording element by the electrical voltage corresponding to the shape of the recording signal or the type of image. In order to obtain a record in which the signal is fully recorded, it is necessary to choose the exposure time from the worst conditions, i.e. from the condition of recording the edges of the signals. This necessitates a reduction in the speed of recording information approximately 62.8 times. When used as a recording element of a beam of light emitted by a CRT, this leads to the fact that at the places corresponding to signal vertices the phosphor operates in a more severe mode, This causes the phosphor to rapidly deteriorate and reduces its light output. Ultimately, this leads to a decrease in the quality of the recorded information and a reduction in the lifetime of a CRT. In addition, in the recording areas of the vertices and fronts of the signals, the recording line width is not the same, since the brightness in the fifth is distributed according to the law of probability distribution or Gauss. Therefore, the longer the exposure time to the recording medium, the greater the width of the recording line. This reduces the resolution and degrades the quality of the recorded information. The aim of the invention is to improve the quality and shorten the recording time. The goal is achieved in accordance with the method of recording seismic signals of a controlled recording element on a carrier, which consists in dividing the seismic signal into two channels, in the first channel the voltage corresponding to one of the types of recording controls the movement of the recording element on the carrier, and in the second channel, the voltage controls the intensity of the impact of the recording element on the recording medium, the seismic signal is converted into a voltage corresponding to one of the types of recording division into two channels, and the exposure intensity control recording element is carried out in proportion to its movement speed by differentiating the voltage on the second channel and its subsequent half-cycle of two righting. The control of the intensity of the effect of the recording element on the recording medium by a signal, the magnitude of which is proportional to the speed of movement of the recording element, helps to level the exposure of all sections of the recording signals on the recording medium. This improves their resolution, reduces blackness and improves visual correlation of regular signals. The latter is achieved by the fact that as a result of an increase in the intensity of the effect of the recording element on the fronts of seismic vibration pulses, the correlated reflections are represented as lines with increased optical density resulting from the transition of the common-mode pulses to each other. Since the lines of these fronts are directed along the line of correlation of the in-phase reflections, their visual correlation is better expressed, and the width of the correlation line is thinner than in the time sections recorded according to the method in which the lines of vertices of the in-phase pulses perpendicular correlation lines. With this method, the seismic waveform is fully preserved, which increases the information content of seismic sections. In general, all this contributes to improving the quality of the recorded information. In addition, controlling the intensity of the electron beam effect on the CRT phosphor proportional to its speed on the CRT screen provides a more complete use of the phosphor's energy potential, which leads to an increase in light output and contributes to an increase in the recording speed without sacrificing the CRT durability and reliability. The method of recording seismic signals is as follows. The recorded seismic signal is converted into a voltage corresponding to one of the types of recording: the amplitude is variable, the width is variable, or a combination of them. Then, the resulting voltage corresponding to one of the recording types is divided into two channels. On the first channel, the movement of the recording element on the recording medium is controlled by the voltage corresponding to one of the recording types, in the second channel the voltage corresponding to one of the recording types is differentiated. The alternating voltage obtained after differentiation is transformed into a unipolar one by a full-wave rectification, the resulting unipolar voltage controls the intensity of the effect of the recording element directly proportional to the speed of its movement along the carrier. FIG. 1 shows a device implementing a recording method; in fig. 2 - graphics, showing the operation of the device. The device contains a write type shaper 1, a deflection amplifier 2, a differentiating amplifier 3, a full-wave rectifier 4, a deflection element of a light beam, for example, an electron-beam tube (CRT) 5, a lens 6 and a photosensitive recording medium 7 mounted on a drum.

A seismic analog signal 8 from a signal source, for example, from a magnetic tape or a digital-to-analog converter, is fed to the input of the imager 1 of the recording type, which converts it into a voltage corresponding to one of the recording types. The voltage from the output of the recorder of the type on the first channel through the amplifier 2 deviations control the movement of the recording element, for example, the beam of light emitted by the CRT phosphor. At the same time, from the output of the writer of the second-channel recording type, the voltage is fed to the input of differentiating amplifier 3. The differentiated signal 9 from the output of differentiating amplifier 3 is fed to the input of the full-wave rectifier 4, from which the unipolar voltage 10 goes to the CRT modulator and controls ray intensity is proportional to the speed of its movement.

The proposed method of imaging seismic signals in comparison with the known ones has a higher resolution of seismic signal recordings and their higher information content, better dynamic expressiveness of seismic signals.

cuts, increased write speed information.

Claims (1)

1. US patent No. 3349407, 346-110, published. 1967. 2 USSR Author's Certificate No. 428330, cl. G 01 V 1/28, 1974 (prototype).