A method for early monitoring of air intrusion

Abstract

The invention belongs to the technical field of monitoring methods, and relates to an early monitoring method for gas intrusion, which is implemented by using an early gas intrusion monitoring device, and a lower pressure measuring device and an upper pressure measuring device are installed on a downhole drill pipe according to a set interval to measure the positions respectively The annular fluid pressure and the annular fluid density are calculated. The installation distance between the lower pressure measuring device and the upper pressure measuring device can be adjusted, which solves the problem that the annular fluid pressure between two close points cannot be measured due to the low density of the downhole fluid. Do not rely on logging while drilling equipment, reduce production costs, increase applicability, use conventional MWD, EMWD or ATWD in the process of oil and gas drilling to monitor the occurrence of downhole gas invasion, realize early detection, timely response, and avoid property and personnel The purpose of loss; the technological process is simple, the principle is scientific and reasonable, the operation is convenient, the practicability is good, the use environment is friendly, the versatility is strong, safe and reliable, and it is easy to popularize and use.

Description

Technical field: [0001] The invention belongs to the technical field of monitoring methods, and relates to an early monitoring method for gas intrusion, which monitors the occurrence of downhole gas intrusion during oil and natural gas drilling, realizes early detection, responds in time, and avoids property and personnel losses. Background technique: [0002] Gas invasion is a phenomenon in which the effective pressure at the bottom of the well decreases during the drilling process, causing the gas in the formation to invade the wellbore; When reaching large fractures or cave gas reservoirs, a large amount of displacement gas may suddenly invade the drilling fluid, and the gas in the gas layer will continuously diffuse into the well through the drilling fluid. When the bottom hole pressure is lower than the formation pressure, the downhole is in a larger In the underbalanced state, the gas flows into or invades the drilling fluid in a large amount from the gas layer in the ...

AI Technical Summary

Problems solved by technology

At present, the gas invasion monitoring methods are generally divided into two categories: one is the gas invasion monitoring method of the drilling fluid pool liquid level, the drilling fluid return flowmeter gas invasion monitoring method and the acoustic wave gas invasion monitoring method. The measurement equipment is installed at the position, and the monitoring of gas intrusion is realized by monitoring the relevant parameters on the surface or near the surface; the other is the gas intrusion monitoring method based on formation resistivity, which realizes the gas intrusion by directly placing equipment in the downhole and detecting the relevant parameters in the downhole. Judgment; these methods have their own characteristics, but they have relatively large limitations when used; the first type of method belongs to the indirect judgment method, and the time lag in discovering gas intrusion is not conducive to the rapid judgment and control of gas intrusion, and does not belong to early monitoring; the second type This type of method belongs to early monitoring, but requires the use of expensive and highly dependent logging-while-drilling equipment; under normal circumstances, the time interval from the discovery of gas invasion to blowout is extremely short, and some are even less than 5 minutes. Early monitoring and identification is an important guarantee to avoid and prevent blowout accidents and realize safe drilling

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