Method for evaluating cement bond quality of two interfaces of cased well

Abstract

The invention relates to a method for evaluating cement bond quality of two interfaces of a cased well. In one embodiment, the method includes the steps that an ultrasonic transmitting device and an ultrasonic receiving device are arranged circumferentially in a spaced mode in the horizontal direction and placed in the cased well; the ultrasonic transmitting device transmits ultrasonic waves to the inner wall of the cased well at the incidence angle theta i, the ultrasonic waves are stimulated in the cased well to form a circumferential mode, various layers of media in the cased well reflect the ultrasonic waves to form reflected waves, and the incidence angle theta i is the included angle between the central axis and the normal at the intersection point of the central axis of the radiant surface of the ultrasonic transmitting device and the inner wall of the cased well; the ultrasonic receiving device receives echo signals, the echo signals are compared with echo signals received in a free casing pipe mode, and the cement bond quality corresponding to the forming position of the echo signals in the cased well is obtained. The directional ultrasonic waves are transmitted, the ultrasonic waves are stimulated in the cased well to form the circumferential mode, echo information is processed, and therefore bond states of different interfaces of well cementation cement can be detected.

Description

technical field [0001] The invention relates to an acoustic logging technology, in particular to a method for evaluating the cement bonding quality of two interfaces (cement and formation interface) of a cased well. Background technique [0002] The detection and evaluation of cement bonding quality in cased wells is of great significance to oil well engineering and oilfield development, mainly including the evaluation of the bonding status of the first interface (casing and cement interface) and the second interface. The earliest CBL / VDL cement bond logging is a commonly used detection method in cementing quality detection. Among them, CBL can be used to quantitatively judge the cement bond quality of the first interface; VDL can be used to qualitatively judge the cement bond quality of the second interface. However, both techniques only measure the average cementation quality within a certain longitudinal distance in the circumferential direction of the cement sheath, whi...

AI Technical Summary

Problems solved by technology

However, due to the influence of various factors on the acquisition signal, there is no application of this technology in the evaluation of the cement bond quality of the two interfaces in the field application examples at home and abroad.

[0004] Most of the cementing quality detection methods and technologies currently used are only suitable for evaluating the cementation quality of the first interface, and there are still some difficulties in the detection of the cementing quality of the second interface

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