Downhole string leak point locating method and device

Abstract

The application provides a downhole string leak point locating method and device. The method comprises: acquiring an acoustical signal from an oil-gas well annulus, subjecting the acoustical signal to autocorrelation analysis, and acquiring an autocorrelation function of the acoustical signal; using time corresponding to a first negative peak point of a time positive axis of the autocorrelation function as first feature time, and using time corresponding to a first positive peak point of the time positive axis of the autocorrelation function as second feature time; acquiring parameter information of an oil-gas well, and calculating along-travel speed of the acoustical signal in the annulus of the oil-gas well to be detected according to the parameter information; locating a downhole string leak point according to the first feature time, the second feature time and the along-travel speed. By using the downhole string leak point locating method and device according to the embodiments of the application, it is possible to quickly and accurately locate a downhole string leak point; economic loss due to well shutoff and production halt is avoided, the cost is low, the precision is high, and the method and device are well applicable to oil-gas wells.

Description

technical field [0001] The application belongs to the technical field of downhole leakage detection of oil and gas wells, and in particular relates to a method and device for locating a leakage point of a downhole pipe string. Background technique [0002] The leakage of the downhole pipe string during the production process of oil and gas wells will cause high-pressure natural gas or formation gas to leak into the annular space, and the annular space will be under pressure, which will bring major safety hazards to the production of oil and gas wells. It is of great significance to realize the location of leakage of downhole pipe string through related methods, which is of great significance for the safety assessment of well killing in annulus zone, the reasonable formulation of repair plan and the improvement of oil and gas well production safety assurance level. [0003] In the prior art, the method for locating the leakage point of the downhole pipe string mainly uses the...

AI Technical Summary

Problems solved by technology

Since oil and gas wells need to be shut down for detection, corresponding economic losses will inevitably be brought about. Therefore, the cost of locating the leakage point of downhole pipe strings in oil and gas wells in the prior art is relatively high, and this method requires a relatively long locating period and complicated operations. , the risk is relatively high

Images