Gel isolation well control method

Abstract

The invention provides a gel isolation well control method. The method includes the steps that heavy sizing caps are injected into annular space between a drilling tool and a sleeve pipe from a well mouth, filling and pulling out are carried out, when a drill bit reaches a safe well section, the drilling tool injects gel into a mineshaft to form a gel section plug, throttling circulation exhausting is conducted on the part, above the gel section plug, of the mineshaft so as to discharge slurry polluted by gas out of the part, above the gel section plug, of the mineshaft, the complexity of downhole conditions is reduced, therefore, the probability of well kick, well blowout and well leakage accidents occurring in the high-temperature and high-pressure gas field well drilling process is reduced, and the purpose of reducing the well control risk is achieved.

Description

technical field [0001] The invention relates to well control technology, in particular to a gel isolation well control method. Background technique [0002] Well control technology refers to the technology of maintaining the pressure balance in the well and avoiding accidents such as well kick, blowout and well leakage by adopting certain methods. Among them, well kick means that when the pressure of the fluid layer in the well is greater than the static pressure of the drilling fluid or well washing fluid column, the fluid or gas in the fluid-containing layer will invade the wellbore, accumulate to a certain amount, and then circulate to the wellhead with the liquid in the wellbore. It forms a boiling shape; blowout refers to the phenomenon that the fluid in the formation is ejected from the ground or flows into other formations in the well; lost circulation refers to the leakage of drilling fluid or other media (cementing slurry, etc.) in the wellbore into the formation po...

AI Technical Summary

Problems solved by technology

[0004] During the drilling process, especially in the drilling process of high-pressure, high-sulfur gas wells, when tripping or other downhole operations where the drilling fluid does not circulate, the safe density window is very narrow. When the density of the drilling fluid is slightly higher, the drilling When the drilling fluid penetrates into the formation, it leads to lost circulation; when the density of the drilling fluid is low, the gas enters the wellbore and accumulates, resulting in complex downhole conditions. When the gas volume reaches a certain level, major safety accidents such as well kick and blowout are caused

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