Drill float valve with automatic protection

Abstract

The invention discloses a drilling tool float valve with an automatic protection function. The drilling tool float valve comprises a valve body, a valve sleeve, a valve seat, a protective cylinder anda mushroom-head valve element, wherein a limiting sleeve is arranged below the mushroom-head valve element, on one hand, it is guaranteed that a mud channel is smooth, and on the other hand, a springis protected against fatigue failure; the protective cylinder is of a floating structure, the protective cylinder can be lowered to form a protective cavity after the mud channel is opened so as to effectively protect a sealing ring, direct impact of mud is prevented, and the service life of the sealing ring can be prolonged; and when the sealing ring is compressed to a set amount, a lower conical limiting surface at the lower end of the valve seat is attached to an upper conical surface of the mushroom-head valve element together to enable the sealing ring to be protected, too large pressureis prevented from damaging the sealing ring, and the service life of the sealing ring and the service life of the spring are prolonged.

Description

Technical field [0001] The invention relates to the technical field of internal blowout prevention tools for oil industry drilling, in particular to a drilling tool float valve with automatic protection. Background technique [0002] In oil, natural gas and other drilling and workover operations, in order to prevent the mud in the annulus from returning to the drill string and spraying onto the drill floor when connecting a single root or tripping, at the same time, to prevent the underlying fluid from being under formation pressure Under the action of the drilling tool, overflow, gush or blowout occurs when entering the drilling tool, and a drilling tool float valve is connected at the bottom of the drill string. [0003] Commonly used drilling tool float valves include arrow type drilling tool float valve and plate type drilling tool float valve. When the pump is turned on, the mud pressure pushes the arrow valve core to move down or the valve plate flips to open the mud channel....

AI Technical Summary

Problems solved by technology

[0004] At present, most of the commonly used floating valves for drilling tools have unreasonable structures. The mud directly erodes the seals and the springs have no limit protection. During the maintenance process, the assembly is difficult and the efficiency is low. During the use, the seal often fails, the spring is prone to fatigue, the failure rate is high, the reliability is low, and the service life is short, which greatly pushes up the drilling cost. When drilling operations, reverse circulation, well kick or blowout occur in the well, the spring fails, and the arrow valve core is not closed tightly, which loses the function of preventing drilling fluid from flowing back and preventing sediment from entering the drill string, and cannot achieve the purpose of preventing plugging and blowout , there is a great potential safety hazard, which puts the drilling operation at great risk, seriously threatens the safety of relevant personnel and facilities, and cannot meet the increasingly harsh downhole working conditions.

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