An Earthquake Receiving System

Abstract

The invention discloses a seismic receiving system. The system comprises a cable and n depth controllers; the sinking depth of the cable varies periodically according to a negative sinusoidal function; and the n depth controllers are hung on the cable and are used for controlling the sinking depth of the cable, wherein n is an integer greater than or equal to 2. According to the seismic receiving system provided by the embodiments of the invention, the cable of which the sinking depth varies periodically according to the negative sinusoidal function is adopted to acquire seismic data; since the sinking depth of the cable varies periodically according to the negative sinusoidal function, time for ghost waves to reach the receiving channel of the cable is different; and after the acquired seismic data are subjected to the superposition processing of a common middle point (CMP), a wave trapping effect can be suppressed, and therefore, the effective bandwidth of the acquired seismic data is wider, and the signal-noise ratio and imaging quality of the acquired seismic data are improved.

Description

technical field [0001] The invention relates to seismic exploration technology, especially to a seismic receiving system. Background technique [0002] In recent years, the development of most offshore oil and gas fields has achieved full coverage of 3D seismic data, and has entered the secondary exploration (or re-exploration) stage for complex structures, lithological traps, and preparation for fine reservoir description. Different from the initial exploration, the new A new round of oil and gas exploration requires seismic data to have a wider effective frequency bandwidth (sufficient data at the low-frequency end and high-frequency end), higher resolution and signal-to-noise ratio, and better imaging quality to reduce the multiplicity of the seismic data itself. Solution. Theoretical research shows that when the frequency bandwidth of seismic data is equal to or higher than twice the frequency range, the imaging accuracy and imaging effect can be guaranteed, that is, th...

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Problems solved by technology

[0003] There are two types of conventional marine seismic receiving systems, such as figure 1 As shown, in order to ensure the maximization of downward transmission energy and reduce the receiving environment noise and other factors, one of the seismic receiving systems includes: the cable is sunk below the sea level at the same depth, and the depth of the cable is equal to or slightly greater than that of the air gun (that is, the depth of the seismic source), the sea level is a strong reflection interface, and the notch point is generated due to the notch characteristic, so that the high-frequency information is often missing in the seismic data, thus narrowing the frequency bandwidth and reducing the resolution. It is difficult to obtain seismic data with a wide frequency band and rich information in the low-frequency and high-frequency bands by changing the source capacity and the depth of the cable.

[0004] Another seismic receiving system includes: cables with varying depths below sea level, which can be roughly divided into three types according to the shape of the cables: the first type of cable is a linear inclined cable or a variable depth cable, that is, a cable with a certain depth The slope of the cable is linearly inclined and placed below the sea level, and the depth of immersion increases successively (as shown in Figure 2(a)); Below sea level (as shown in Figure 2(b)); the third type of cable is a slide-type inclined cable, that is, the cable is divided into sections of different lengths in the form of a slide and placed at different depths, and the middle is connected by a linear inclined cable (as shown in Fig. 2(c)), the cables in this seismic receiving system have changed their depth to suppress the notch effect generated by the sea level, so as to obtain sufficient seismic data at both low and high frequencies, increasing the The frequency bandwidth of the seismic data, but the energy is reduced at the 1 / 2 notch frequency point and the ripple oscillation effect appears at the high frequency end

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