Three-component digital seismic exploration wave detector

Abstract

The three-component digital seismic exploration geophone is characterized by that three MEMS acceleration sensors are arranged according to the direction in which X-axis, Y-axis and Z-axis are mutually perpendicular, their signal outputs are connected with three 24-bits A / D covnerters, then passed through the chip microprocessor with CAN bus so as to can directly output the digitized seismic signal with good low-frequency resposivity and high vector fidelity.

Description

Technical field: [0001] The invention relates to a device for detecting reflected waves of artificially excited seismic signals in seismic exploration and converting them into electrical signals, belonging to the field of seismic exploration. Background technique: [0002] Geophones are widely used sensors in oil and gas seismic exploration, and their purpose is to detect artificially induced seismic signals in seismic exploration. [0003] Seismic prospecting is still the main method for oil and gas exploration on land and sea. The basic method is to bury thousands or even tens of thousands of seismic wave sensors (ie, geophones) on the ground of the exploration target area, and to drag and drop several 1-2 km long offshore floating cables ( Floating cables wrap a seismometer every tens of meters), and then use explosives (on land) or high-pressure air guns (on sea) to stimulate artificial earthquakes. Seismic waves propagate deep underground, and they will be reflected w...

AI Technical Summary

Problems solved by technology

Although after 50 years of continuous improvement and development, the moving coil electromechanical induction sensor has been greatly improved in terms of size, robustness, sensitivity, distortion and other technical performances, but the inherent shortcomings of this old-fashioned traditional geophone have not been able to To overcome, for example, it is powerless to detect deep low-frequency seismic signals below 10HZ (10HZ is the resonance frequency of the mechanical geophone); the dynamic range is small (less than 60dB, while the digital seismic instrument has a dynamic range of 120dB); in three-component seismic exploration (using Three moving-coil geophones receive seismic signals in X, Y, and Z dimensions at the same time) There are fatal shortcomings such as large signal crosstalk between each axis (that is, low vector fidelity) and large sensitivity errors

As the first process of seismic exploration, the fact that traditional geophones cannot obtain ideal original signals has directly affected the quality of seismic data acquisition, limiting the ability of geophysical methods to solve complex geological targets, and has become a constraint for petroleum geophysical prospecting. Major bottlenecks for continued technology development

[0005] At present, in the petroleum industry, although it has long been known theoretically that the use of shear wave component (S wave) data in seismic waves can analyze and study reservoir characteristics such as lithology, porosity and oil saturation of underground structures, but this use The exploration of shear wave information has not made much progress

Reservoir characterization for enhanced recovery is still dominated by traditional seismic methods based on compressional waves (P waves), mainly because of the quality of shear wave data obtained in 3-component seismic surveys with conventional geophones. far from ideal

In particular, it is difficult for traditional geophones to meet the required inter-axis anti-interference performance index (i.e., vector fidelity index), coupled with factors such as the inclination angle and azimuth error of the geophone during field construction, and the sensitivity error between each axis, etc. The P wave and S wave signals in the received data are mixed with each other, so that the quality of the original data is too poor, and the later data processing methods cannot play a role at all.

[0006] With the requirements of high resolution, high fidelity and high precision in seismic exploration, many companies and research institutions at home and abroad have been exploring and looking for new sensor technologies for seismic signal detection for many years, and have carried out many experiments. Some experimental products using the principles of piezoelectric ceramics, eddy current, and laser have been launched, but there has been no major breakthrough in key performances such as poor low-frequency response performance, small dynamic range, and poor vector fidelity mentioned above.

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