Earthquake speed disturbance modeling method for well-free earthquake reversion

Abstract

The invention discloses an earthquake speed disturbance modeling method for well-free earthquake reversion. The method comprises the following steps: obtaining a longitudinal wave model vp of a deep-water well-free work area, and calculating a transverse wave model vs by taking a background mud stone vp / vs as a constant; according to experience information of the deep-water work area, selecting a constant from a scope of [1.90-2.10] for the vp / vs, selecting a starting point value starting from vp / vs=1.90, carrying out disturbance change according to a mode that a set step length is sequentially increased, forming a vp / vs model array taking the set step length as an interval, and accordingly, obtaining the transverse wave model vs of disturbance corresponding to each progressively increased number; and solving a density model den, a longitudinal wave impedance model zp and a transverse impedance model zs, and taking the multiple models as input of a reversion model for reversion. The method provided by the invention has the following advantages: the operation is simple, the modeling is convenient, the accuracy and the reliability are high, the practicality is high, the modeling is carried out by reliance on a disturbance method of a speed field, a stable reversion result is obtained, and the modeling is realized effectively and rapidly.

Description

technical field [0001] The invention relates to a modeling method, in particular to a seismic velocity disturbance modeling method for seismic inversion without a well, which belongs to the seismic inversion modeling technology of petroleum exploration. Background technique [0002] Seismic pre-stack synchronous inversion technology is often used to identify reservoirs and detect hydrocarbons. The so-called pre-stack synchronous inversion refers to the joint inversion of different offset gather data and P-wave, shear-wave, density and other logging data to obtain the It is a new technology for comprehensively judging reservoir physical properties and oil and gas properties based on a variety of elastic parameters related to gas-bearing properties. Currently, there are two mainstream pre-stack synchronous inversion methods: model-based pre-stack synchronous inversion and seismic trace-based pre-stack synchronous inversion. [0003] Before inversion, these two types of method...

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Problems solved by technology

[0005] The above-mentioned modeling method is generally used in areas with wells. However, for many new exploration areas, such as the deep water area of ​​the South China Sea, the water depth is about 2000ms, and the drilling cost is generally more than 100 million yuan. There is not a single well in the entire work area, which brings difficulties to the modeling. Modeling is crucial for the subsequent inversion

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