A method and device for detecting the depth of casing leaks in oil production wells

Abstract

The invention discloses a casing leakage point depth detecting method and device for an oil extraction well. According to the method, after fluid in a wellbore of the oil extraction well reaches a quiescent state, tagged particles are added into the wellbore, and the moment t when the tagged particles are added is recorded; then a decompression valve is opened to enable the annular pressure at a casing leakage point of the oil extraction well to be lower than the wellbore pressure of the oil extraction well, the purpose that the tagged particles can be sprayed out through the leakage point in a casing along with the fluid in the wellbore at a fast speed and impact the inner wall of an intermediate casing and the outer wall of an oil-string casing is ensured, and then impact signals on the casing walls are collected; the impact signals are compared and analyzed in real time through a computer, and the moment t1 in the impacting signals including the signals of impacting of the tagged particles on the casing walls is recorded and judged; and then the distance from a well mouth of the oil extraction well to the leakage point of the casing is calculated according to the formula (please see the specifications for the formula), so that quick and effective depth detecting of the casing leakage point is achieved, complexity and high cost of casing leakage point depth detecting are lowered, and assistance is provided for safe production of the oil extraction well.

Description

Technical field [0001] The embodiment of the present invention relates to the technical field of oil and gas development, in particular to the technical field of casing leakage detection technology, and in particular to a casing leakage detection method and device for oil production wells. Background technique [0002] With the continuation of the oilfield development time, due to external forces, chemical damage, etc., the oil production casing may have problems such as misalignment, perforation, corrosion, rupture, etc., which will have a greater impact on the increase and stability of the oilfield, and even cause the oil well to stop or scrap. Bring high economic losses. Therefore, when the casing is damaged, finding and determining the depth of the leak in time is of great significance to the remediation and maintenance of oil and gas wells. [0003] At present, there are many theories and methods for detecting leaks in oil production casing, including electromagnetic method, ...

AI Technical Summary

Problems solved by technology

These detection methods have their own advantages and disadvantages. For example, the electromagnetic method can analyze and calculate the change of the casing material, corrosion, cracks and other information based on the change of the induced electromotive force, and determine the damage of the casing. However, the detection cost is high and the true shape of the pipeline cannot be simulated. ; The mechanical caliper method can measure many independent caliper information, but it cannot realize fast detection; the ultrasonic method can visually display the detection results in the form of images, but the measurement requires high imaging resolution of the instrument, and the detection efficiency is slow; the optical method The bottom hole camera logging system can accurately, intuitively and clearly display the image of any position in the well, but the measurement is not suitable for oil wells with a large oil-water mixing ratio and relatively high suspended matter content

Images