Small Refraction Single Detector

Small Refraction

Principle: In fields such as oil and gas exploration, controlled seismic sources are used to generate artificial seismic waves on the ground. When artificial seismic waves propagate underground, if they encounter an interface between different media, and the seismic wave propagation velocity in the lower medium is greater than that in the upper medium, the seismic wave will be incident on the interface at a critical angle, generating a refracted wave that slides along the interface in the lower layer, causing disturbances in the upper medium. At the same time, the seismic wave that propagates directly from the controlled seismic source to the geophone is the direct wave. By analyzing the relevant information of the direct wave and the refracted wave, such as using the position parameters of the geophone and the controlled seismic source to draw a time-distance curve, the relevant seismic parameters of the refracted wave and the direct wave can be calculated, thereby studying the surface structure.

Application: Mainly used for near-surface structure detection, such as understanding the velocity distribution and depth information of different strata below the surface, which plays an important role in determining underground geological structures and stratigraphic layering in seismic exploration, providing basic data for subsequent oil and gas exploration.

Single Geophone

Working Principle: A geophone is a device that detects a certain type of useful information in a wave signal, used to identify the presence or change of waves, oscillations, or signals and extract the information they carry. Common effect geophones utilize the rectification effect of transistors or diodes to convert AC signals into DC signals. For example, when the forward bias voltage of a transistor or diode is greater than the threshold, it conducts, converting the positive half-cycle AC signal into a DC signal output, thereby separating the carrier frequency and information signal in the modulated signal. For a single geophone in seismic exploration, it senses ground vibrations and converts mechanical vibrations into electrical signals, recording the ground vibrations caused by the propagation of seismic waves to that point.

Characteristics and Applications: Compared with geophone arrays, single geophones have unique advantages in seismic exploration. In areas with irregular terrain, dense vegetation, or inconsistent ground coupling, using a single geophone for single-point reception can avoid poorly coupled areas and reduce the introduction of random noise. At the same time, single geophone reception allows the desired combination forms to be constructed in the data processing center, omitting a large number of test shots in the acquisition process, reducing field costs, and making the data more faithful to the acquisition.