Scattered wave pre-stack imaging method for identifying small-fault throw breakpoints

Abstract

The invention relates to a scattered wave pre-stack imaging method for identifying small-fault throw breakpoints, which is applied to processing of seismic reflection information in seismic exploration and is of a seismic imaging method of a micro-small fault for identifying the underground geological structure. According to the method, scattered waves of the breakpoints of the fault are utilized for independent imaging of the breakpoints with the fault throw of less than 1 / 4 wavelength, which are difficult to identify by conventional reflected wave migration. According to the method, the existing seismic reflection information is utilized, and the independent imaging of the small breakpoints is realized by pressing the energy of transmitted waves in pre-stack migration calculation and utilizing the polarity inversion characteristic of the scattered waves of the breakpoints. Pre-stack time migration is taken as the basis, an angle gather is generated by migration of single-shot information, and a Fresnel zone corresponding to an inphase axis of reflected waves is excised so as to eliminate the transmitted waves. According to the method, the small fault and breakpoints of the underground structure can be indicated in a fine manner, migration and plugging of underground oil gas can be better known, and the method further has an important application value for exploration and development of oil gas resources. The ability to identify the underground deep fissures and fault of the seismic exploration method is significantly improved.

Description

technical field [0001] The invention belongs to the technical field of reflection seismic data processing in seismic exploration, relates to the category of pre-stack migration imaging technology in the process of seismic data processing, and is a migration imaging method that can identify microfaults in geological structures that are difficult to clearly distinguish by conventional migration methods . Background technique [0002] In oil and gas exploration, the accurate identification of small faults and small faults is an important link in understanding the oil and gas dredging system, and then identifying favorable reservoirs. Therefore, improving the resolution of migration imaging has always been an important goal in the processing of reflection seismic data in seismic exploration. [0003] The current migration imaging methods of seismic data are all based on the correct homing of the reflected waves of the underground interface to realize imaging. The interface ref...

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Problems solved by technology

However, in the case of complex geological structures, the characteristics of interface reflection waves become more complex, especially in the case of low signal-to-noise ratio of seismic data, it is almost a difficult task to accurately identify the reflection wave event and correctly eliminate it; in addition, Transformation methods such as Ladang transformation will also destroy the originally weak scattered wave

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