Method for joint inversion of longitudinal wave impedance and transverse wave impedance by using prestack data of PP and PS waves

Abstract

The invention discloses a method for joint inversion of longitudinal wave impedance and transverse wave impedance by using the prestack data of PP and PS waves. The method comprises the following steps of: acquiring time windows, trace windows and line windows, on a PP-wave section plane and a PS-wave section plane which are actually measured, of a reservoir to obtain PP-wave seismic records and PS-wave seismic records of all common depth point (CDP) ranges and all offset distances of the reservoir; processing each sampling time in the time windows [tpp1, tpp2] and [tps1, tps2] of a common middle point (CMP) gather or a common reflection point (CRP) gather of a PP-wave and a common conversion point (CCP) gather of a PS-wave of the CDP; obtaining a PP-wave seismic record of an approximate zero offset distance and an SS-wave seismic record of a zero offset distance in the time window at the CDP; and performing inversion on the PP-wave seismic record of the approximate zero offset distance and the SS-wave seismic record of the zero offset distance to obtain the longitudinal wave impedance Ip and the transverse wave impedance Is. By the method, the longitudinal wave impedance and the transverse wave impedance of the reservoir are inverted conveniently and rapidly; elastic parameters of the reservoir per se can be acquired stably; and the accuracy of the lithological and physical descriptions of the reservoir is improved.

Description

technical field [0001] The invention relates to a method for joint inversion of longitudinal and shear wave impedance by using PP and PS wave prestack data, and belongs to the field of geological exploration or seismic exploration. Background technique [0002] In the prior art, there is a strong multi-solution between the elastic parameters of the reservoir obtained only by PP wave inversion and the lithology and physical properties of the reservoir. With the acquisition of PS wave data, the elastic parameters of the reservoir obtained by PS wave inversion can be interpreted together with the elastic parameters of the reservoir obtained by PP wave inversion due to the fact that S wave does not propagate in the fluid, which provides a basis for weakening the reservoir. The possibility of multiple solutions between elastic parameters and reservoir lithology and physical properties improves the accuracy of reservoir interpretation. However, previous studies have shown that th...

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Problems solved by technology

However, these parameters involve the combination of the elastic parameters of the overburden layer or the underlying layer of the reservoir and the reservoir itself, which makes the interpretation of these parameters more complicated, the description of the reservoir is not intuitive, and it is not easy to be widely used

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