Variable-diameter blocking flow dividing device

Abstract

The invention discloses a variable-diameter blocking flow dividing device. The variable-diameter blocking flow dividing device comprises a flow dividing short joint, a sliding blocking short joint anda sliding pressure exerting short joint, when a spline sleeve is located on the upper supporting point relative to a spline shaft, a boss of the sliding blocking short joint is inserted into a flow dividing short joint groove A to divide a large annulus into an upper large annulus and a lower large annulus, well drilling media reversing out of the lower large annulus sequentially pass through a side channel B, a side channel A and a main channel B to enter a dual-wall drilling tool reversing-out channel, when the spline sleeve is located on the lower supporting point relative to the spline shaft, and the upper large annulus and the lower large annulus communicate through a groove A and a groove B. The variable-diameter blocking flow dividing device has the following advantages that the upper large annulus is blocked, and positive and negative alternative gas reverse circulation well drilling is achieved; and under the non-drilling condition, the upper large annulus and the lower largeannulus of a blocking device are in the communication state, the drilling tool jamming risk of the blocking flow dividing device can be reduced, and the condition is provided for solving complex problems by using positive circulation.

Description

technical field [0001] The invention relates to a plugging diverter, in particular to a variable-diameter downhole plugging diverter for reverse circulation drilling. Background technique [0002] During drilling, the method in which the circulating medium carries cuttings or core from the bottom of the well to the surface from the center of the drill pipe is called reverse circulation center sampling drilling. Single-layer, double-layer or triple-layer drill pipes are usually used, but double-walled drill pipes are the most common. The circulating medium is pressed in from the annular space between the double pipes, and the cuttings (core) are carried back from the center of the inner pipe, so this method is called double-pipe reverse circulation or double-wall drill pipe reverse circulation drilling. With the continuous innovation of reverse circulation drilling theory and drilling technology, reverse circulation drilling technology has been widely used in mineral explora...

AI Technical Summary

Problems solved by technology

During the use of conventional downhole plugging diverters, the large upper part cannot fall to the lower part of the plugging diverter, causing the risk of pipe sticking, and conventional pluggers are generally full-hole pluggers, when reverse circulation is used to deal with complex problems such as pipe sticking When there is difficulty and need to turn positive circulation, the drilling fluid cannot enter the upper annulus through the plugger, resulting in complex failure of treatment

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