Method for obtaining casing and cement interface shear coupling stiffness from cased well acoustic logging

Abstract

The invention discloses a method for obtaining casing and cement interface shear coupling stiffness from cased well acoustic logging. A sliding interface boundary condition is adopted to describe a non-good contact interface between a casing and a stratum, and the boundary condition is introduced into the field of well cementation acoustic logging. A well cementation acoustic logging model characterized by a slip interface is adopted to effectively simulate various complex coupling conditions of the casing and the stratum. Compared with an existing classical theory, by using the method of theinvention, an acoustic logging response problem of the cement interface under a complex cementing condition from complete non-cementing to complete cementing and in a transition state can be described, and a new way is provided for solving practical application problems.

Description

technical field [0001] The invention belongs to the fields of geophysical well logging and oil and natural gas exploitation. Background technique [0002] Well cementing is an essential part of well completion engineering in the petroleum industry. The quality of cementing is related to the life of oil and gas wells, safe production and overall benefits. In order to accurately evaluate the quality of cementing, the development and application of various detection technologies has formed an industry. Acoustic logging is one of the most important evaluation techniques. It mainly uses the amplitude or attenuation of the acoustic wave propagating along the casing to evaluate the cementation between casing and cement (first interface) and between cement and formation (second interface). degree. In the classic elastic wave theory, the layered model is often used, and the casing, cement and formation are represented by a series of columnar layered bodies; when the first or secon...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for obtaining the shear coupling stiffness of casing and cement interface from cased well acoustic logging, so as to solve the problem of shear coupling stiffness between casing and cement or between cement and formation obtained through casing wave amplitude inversion. Cut the coupling stiffness, the technical problem of quantitatively evaluating the cementing quality of the cased well with the size of the coupling stiffness

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