RU2672290C1 - Overflow valve of drill column - Google Patents

Abstract

FIELD: drilling of soil or rock.SUBSTANCE: invention relates to the field of well drilling and repair, in particular to devices for communicating the internal cavity of a process pipe string with annular space when carrying out tripping operations to fill the column with borehole fluid and emptying, namely to the overflow valves of the drill string. Device includes hollow body 1 consisting of upper 2 and lower 3 half-shell. Hollow piston 4 is installed in the upper half-shell with the possibility of opening drain radial 5 holes and is made differential – at the top of a smaller diameter, at the bottom of a larger diameter. Seals 6 and 7 on cylindrical surfaces 8 and 9 mating with the upper half-body are provided with an interference tightening that ensures the retention of the hollow piston in the upper half-shell. In distributor 10, pressed in the lower half-body, there are radial inlet ports 11 connecting inner cavity 12 of the distributor with space 13, as well as longitudinal bypass channels 14 connecting cavity 15 of the upper half-shell with space 16 under the distributor. Seat 17 to which conical core 18 with seal 19 and spring 20 interacts, is mounted in cap 21 connected to the distributor.EFFECT: reliability and durability of valve operation in the drill string is increased.1 cl, 3 dwg

Description

The invention relates to the field of drilling and well repair, in particular, to devices for communicating an internal cavity of a pipe string with an annulus during hoisting operations to fill the string with well fluid and emptying, namely, overflow valves of the drill string.

The closest device of the same purpose to the claimed invention is an overflow valve of the drill string, including a vertical hollow body with radial holes, a valve pair with a saddle and a hollow piston (RF Patent No. 2204688, CL ЕВВ 21/10, 2001).

A disadvantage of the known valve is that it is prone to sludge (clogging by particles of the solid phase of the process fluids) of the radial holes that impede the emptying of the pipe string from the fluid when lifting from the well, which affects the reliability of the device.

The technical result of the invention is to increase the reliability of the overflow valve.

This result is achieved by the fact that in the overflow valve of the drill string, including a vertical hollow body with radial holes, a valve pair with a seat and a hollow piston, the body is made up of upper and lower half bodies, the hollow piston is made differential - from above with a smaller diameter, and below with a large and installed in the upper half-housing with the possibility of overlapping radial holes in the wall of the upper half-housing, the device is also equipped with a flow distributor, pressed inside the lower half-housing and equipped with radial inlet openings with the possibility of combining them with radial holes in the wall of the lower half-housing for connecting the inner cavity of the distributor with the housing space, as well as longitudinal bypass channels connecting the cavity of the upper half-housing with the space under the distributor, and the valve pair is equipped with a distribution cap and a spring-loaded conical core, mating with a saddle.

Improving the reliability of the valve is achieved by dividing the radial holes into inlet openings located in the lower half-housing and drain holes made in the upper half-housing. The latter, protected by a differential hollow piston, are not clogged with dirt neither during the descent of the valve, nor during its operation in the well and provide reliable emptying of the process pipes.

The invention is illustrated by drawings.

In FIG. 1 shows a General view of the overflow valve of the drill string during transportation (descent) into the well;

in FIG. 2 is a transverse section aa of the lower valve half-housing;

in FIG. 3 is a view of a valve with open drain holes when lifting from a well.

The overflow valve of the drill string (Fig. 1) includes a hollow body 1, consisting of upper 2 and lower 3 half-shells. The hollow piston 4 is installed in the upper half-housing with the possibility of opening the drain radial 5 holes and is made differential - at the top of a smaller diameter, at the bottom of a larger diameter. Seals 6 and 7 on the mating cylindrical surfaces 8 and 9 mating with the upper half-housing are tightened to ensure that the hollow piston is held in the upper half-housing.

In the distributor 10, pressed into the lower half-housing, radial inlets 11 are made connecting the inner 12 cavity of the distributor with the housing 13, as well as longitudinal bypass channels 14 connecting the cavity 15 of the upper half-housing with the space 16 under the distributor. The saddle 17, with which the conical core 18 interacts with the seal 19 and the spring 20, is installed in the cap 21 connected to the distributor.

The overflow valve operates as follows.

The valve is lowered into the borehole on technological (drill or tubing) pipes connected by the hollow body 1. During the descent, during immersion in the borehole fluid (Fig. 1), fluid from the housing 13 flows through the radial inlets 11 into the inner 12 cavity of the distributor 10 of the lower half housing 3, repels the core 18 with the seal 19 from the seat 17 and compresses the spring 20, installed in the cap 21. The fluid flows through the gap between the seat and the core into the cavity 15 of the upper 2 half-housing, then through the hollow piston 4 it fills the process pipes. When the descent stops and the pressure of the borehole fluid is equalized between the housing space, the spring returns the core to its original position with emphasis on the saddle.

In the process of pumping the working fluid through the process pipes due to almost equal pressure above the piston 4 and below it, due to the larger area of the lower part of the piston with a cylindrical surface 9 than its upper part with a cylindrical surface 8, a greater pressure force acts from below from above. This force is greater than the hydrodynamic pressure of the fluid flow to the piston. Thus, the piston is pressed into a conical ledge in the upper 2 half-housing and is kept from falling down.

The liquid begins to flow through the longitudinal bypass channels 14 and the space 16 under the distributor 10 into the lower part of the arrangement of process pipes and equipment (not shown in the drawings).

After completing the flushing of the well at the wellhead, ball 22 (Fig. 3) is dropped into the column of process pipes, which sits on the conical groove of the hollow piston 4 and pushes the piston with seals 6 and 7 down under pressure of the working fluid pumped into the column, which lowers with the ball to the cap 21. The working fluid flows when the valve is lifted from the well through the radial drain 5 holes of the upper half-body 2 into the housing 13.

Using the proposed technical solution provides increased reliability and durability of the overflow valve of the drill string.

Claims (1)

Drill string overflow valve, comprising a vertical hollow body with radial holes, a valve pair with a seat and a hollow piston, characterized in that the body is made up of upper and lower half bodies, the hollow piston is made differential - from above with a smaller diameter, and below with a large one, and is installed in the upper half-housing with the possibility of overlapping radial holes in the wall of the upper half-housing, the device is also equipped with a flow distributor, pressed inside the lower half-housing and equipped with radial inlets openings with the possibility of combining them with radial holes in the wall of the lower half-housing for connecting the inner cavity of the distributor with the housing space, as well as longitudinal bypass channels connecting the cavity of the upper half-housing with the space under the distributor, and the valve pair is equipped with a distribution cap and a spring-loaded conical core mating with saddle.

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