Method and device for reclaiming drill stems in accidental wells

Abstract

The invention discloses a method and a device for reclaiming drill stems in accidental wells. The device mainly comprises an upper shell, seal rings, a mandrel, a spring, a lower shell and a pressure holding ball. The upper shell and the lower shell are in threaded connection and connected with an upper drill stem and a lower drilling tool respectively. The mandrel is in splined connection with the upper shell and the lower shell, the spring is arranged between the mandrel and the lower shell, and the seal rings are arranged between the outer wall of the upper end of the mandrel and the inner wall of the upper shell and between the outer wall of the lower end of the mandrel and the inner wall of the lower shell respectively. When the drill stem in the well cannot be taken out, the pressure holding is put into the drill stem from the ground and moves annularly along the drill stem to an inverted conical flow passage on the mandrel, a slush pump is started to enable the pressure holding ball to hold the pressure for pushing the mandrel to move downwards, a spline of the mandrel is separated from an upper key groove, a box of the upper shell and a pin of the lower shell are in left-hand thread connection, the upper shell and the lower shell are separated when the drill stem is rotated rightwards, and the upper shell and drill stem can be lift out of a drill hole consequently.

Description

technical field [0001] The invention relates to a device and a method for recovering a drill string in an accident well, and belongs to the technical field of drilling such as oil and gas exploitation. Background technique [0002] Drilling is a necessary process for oil and gas production. It is characterized by the high-speed rotation of the drill string system driven by the ground rotary table, and the drill string acts on the rock through its own weight to continuously extend the wellbore. For the drill string, it has a large length-to-diameter ratio. During the drilling of deep wells, ultra-deep wells or hard formations, there are often cases of drill bit sticking. For example, in the development of some old wells, due to problems such as borehole bending and borehole diameter shrinkage, there is often a phenomenon that the drill string in the borehole cannot be taken out due to the sticking of the drill bit or the lower drilling tool. For the problem of drill bit or l...

AI Technical Summary

Problems solved by technology

These processes can solve most of the problems in the field related to bit or lower hole sticking, however, there are still situations where the sticking problem cannot be solved

In this case, rotating the drill string counterclockwise can remove some of the drill string, but one cannot control how much is removed

Under the action of this random factor, there is a possibility that a large number of drill strings will be scrapped together with the wellbore

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