RU2426862C1 - Drill circulating valve - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: circulating valve consists of coaxial case and piston inter-engaged by means of pins and slots. The first system consists of a case, of a closer with channels communicating an internal cavity of the system with annular space of a well, of a packing, of an upper and lower arresters of piston travel; while the piston system consists of the piston with a throughput channel and a packing, of a valve switch with radial channels and of a compression spring. The throughput channel of the piston converges at an inlet section and diverges at an outlet section. At a section of maximal convergence a bypass channel is made in the piston; the channel hydraulically communicates the throughput channel with a behind-the piston cavity. ^ EFFECT: reliability of valve, reduced output of hydraulic power for drilling and hole conditioning. ^ 4 cl, 9 dwg

Description

The invention relates to devices for drilling deep wells, namely to submersible surface-controlled valves.

Known drill overflow valves (see, for example, RF patent No. 2204688), with which the filling and emptying of the drill string during tripping during the construction of the well are provided.

With a small supply (flow) of drilling fluid, these valves can operate in the wellbore flushing mode without pumping the fluid through the downhole motor. However, at low flow rates, it is not possible to completely flush the well. Therefore, for flushing the well with a high flow rate, a circulation valve is used.

A known circulation valve (US patent No. 4.298.077 from 11/03/1981). A relatively large pressure and hydraulic power are expended on the operation of this circulation valve. In addition, at low liquid flow rates, the differential pressure across the valve piston is not enough to create the necessary effort to switch it.

A known circulation valve operating in a wide range of fluid flow rates (US patent No. 6.095.249 from 01.08.2000 - prototype). This valve includes coaxial, interlocked by means of spikes and guide grooves of the housing and piston systems, the first of which contains a pipe with channels communicating its internal cavity with the annulus of the well, a contactor, upper and lower piston stroke limiters, and the second contains a piston with a flow channel and a seal, a valve switch with radial channels, a compression spring located in the piston space between the ledge of the piston and the lower limiter of its stroke. The necessary pressure difference across the valve piston is created by installing additional hydraulic resistance in the flow channel of the piston, which requires appropriate valve readjustment. However, the problem of additional losses of hydraulic power is also not solved.

In addition, the movement of the piston (emptying and filling the piston cavity) in the prototype is carried out with hydraulic connection of the piston cavity with the annular space of the well, which causes clogging of the spring and, as a result of this, loss of performance.

The present invention seeks to remedy the noted drawbacks. This is achieved by the fact that in the known circulation valve, including coaxial, being engaged with each other by means of spikes and guide grooves of the housing and piston systems, the first of which contains the housing in the form of a nozzle, a contactor with channels communicating its internal cavity with the annular space of the well and the seal, the upper and lower piston stroke limiters, and the second contains a piston with a flow channel tapering at the inlet and a seal, a valve switch with radial channels, a compression spring located in the piston cavity between the piston ledge and the lower stroke limiter, the piston flow channel is made with a variable cross section from tapering in the inlet section to smoothly expanding in the output section, while in the piston maximum narrowing section there is a bypass channel hydraulically communicating the flow channel with the piston cavity . Thanks to this technical solution, it is possible to create a zone of low static pressure in the piston cavity and, accordingly, to realize an increased pressure drop to move the piston.

In addition, in the valve, the piston cavity is hydraulically disconnected from the annular space of the well by installing a seal between the contactor and the piston.

In the proposed technical solution of the circulation valve, the spikes are installed in the housing system, and the guide grooves are made outside the piston in a closed circuit with an open exit to the piston ledge.

In addition, the flow channel of the piston at the outlet is made with a slope of 3 ... 5 °, and a thrust bearing is installed between the piston step and the spring or between the spring and the piston stroke limiter.

Figure 1 shows a circulation valve (longitudinal section) operating in the overflow valve mode (upper position of the piston).

Figure 2 shows the design of the circulation valve, in which the casing consists of two parts - casing and intermediate sleeves.

On figa shows the circulation valve in the closed state (lower position of the piston, the drilling process).

On figb shows a circulation valve operating in the flushing mode of the well (middle position of the piston).

Figure 4 shows an embodiment of the guide grooves of the piston with the movement of the spike in the guide grooves when changing the positions of the piston in a closed loop.

Figure 5 shows an embodiment of the guide grooves with the movement of the spike in the guide grooves along a continuous comb.

6 and 7 show cross sections of the valve along the spike and along the radial channels of the housing.

Figures 8 and 9 show valve designs with a thrust ball bearing mounted in the piston space between the piston stop and the piston stroke limiter above the spring (Fig. 8) and under the spring (Fig. 9).

The circulation valve (Fig. 1) includes a housing 1 made in the form of a pipe with connecting threads 3, 4, a closure 16 with channels 2 communicating the internal cavity 8 with the annular space 14 of the well, and seals 11 and 24, the upper 17 and lower 18 limiters the piston stroke, the piston 5 with the flow channel 19 and the seal 10, the switch 20 with the radial channels 21, the spring 9 located in the piston space 15 between the ledge of the piston 22 and the lower limiter 18 of the piston stroke.

The flow channel of the piston 19 is made tapering at the inlet portion and gradually expanding at the outlet. In the section 12 of the narrowing of the flow channel 19, a bypass channel 13 is made, which communicates the flow channel 19 with a piston cavity 15.

Thanks to the installation of the seal 11 between the contactor 20 and the switch 16, the piston cavity 15 is disconnected from the annular space 14 of the well.

In the embodiment of the valve shown in figure 1, the spikes 7 are installed in the housing 1, and the guide grooves 6 are made outside the piston 5. The guide grooves (figure 4) have a closed circuit with an open exit to the ledge 22 (figure 1) of the piston 5 and the guide grooves shown in FIG. 5 have a continuous comb configuration.

The flow channel 19 at the outlet section 23 is made with a slope of 3 ... 5 °. To improve the circumferential movement of the piston 5 relative to the housing 1 between the spring 9 and the shoulder 22 of the piston or the piston stroke limiter 18 (Fig. 1), a thrust bearing 26 (Fig. 8, 9) is installed.

Alternatively, to improve manufacturability, the housing can be made integral and include two parts: an intermediate sleeve 25 (Fig. 2) with a closure 16, channels 2, seals 11 and 24, a lower stopper 18 of the piston stroke, spikes 7, and a housing sleeve 27 with threads 3 , 4 and channels 28 for communicating channels 2 with the annulus 14.

The circulating drilling valve operates as follows.

The valve is installed above the hydraulic downhole motor (not shown).

During tripping operations, the piston 5 of the valve (FIG. 1) occupies an upper position relative to the housing 1, which ensures free flow of the drilling fluid during descent from the annular space 14 of the well into the internal cavity 8 and further into the flow channel 19, and during lifting, from the flow channel 19 into the annular space 14. In this way, the drill string is filled and emptied.

When the drilling fluid is supplied from the surface through the drill pipes, the piston 5 is affected by the force determined by the pressure difference at the inlet and the piston cavity 15. By performing the bypass channel 13 at the narrowing point 12 of the flow channel 19, low pressure is provided in the piston space 15 and, accordingly, a large force under which the piston 5 moves downward (in the direction of the drilling fluid), overcoming the elastic resistance force of the spring 9. In this case, the piston 5 can take two positions relative to the housing 1 Eden.

As shown in figure 2, the piston 5 has moved to its lowest position. In this case, the flow channel 19 was disconnected from the cavity 8 and the annular space 14 and the entire drilling fluid is directed to the downhole motor for the implementation of the drilling process.

After stopping the flow of drilling fluid, the piston 5 under the action of the elastic force of the compressed spring 9 returns to its upper position. When re-supplying the solution, the piston 5 will move down to its middle position (Fig.3b), in which a message is established between the flow channel 19, the cavity 8 and the annular space 14 of the well. The supplied drilling fluid only flushes the wellbore.

Switching the valve from flushing to drilling mode is due to the interaction of the spikes 7 with the guide grooves 6 (4, 5). The positions 7a and 7c of the stud relative to the guide grooves correspond to the upper position of the piston 5, the position 7b of the stud corresponds to the lower position of the piston and the position 7d of the stud to the middle position of the piston.

Reducing the cost of hydraulic power in the valve is achieved by the fact that at the output smoothly expanding section 23 of the flow channel 19 with the declared slope, almost complete restoration of static pressure occurs.

The execution of the bypass channel 13 with a small cross-section allows you to connect to its main function also the additional function of a hydraulic damper, softening the contact of the piston 5 with its travel stops 17, 18, as well as the contact of the cleat 7 in position 7d (Figs. 4, 5) with the guide grooves 6 .

Thanks to the installation of the seal 11 in the closure 16 at any position of the piston 5, the piston cavity 15 is protected against penetration into it during drilling of the drilling fluid with drilled rock particles from the annular space 14.

The present invention improves the reliability of the circulation valve, reduces the cost of hydraulic power for drilling and flushing the wellbore.

Claims (4)

1. The circulation drilling valve, including coaxial, meshed with each other by means of spikes and guide grooves of the body and piston systems, the first of which contains the body in the form of a pipe, a closure with channels communicating its internal cavity with the annulus of the well, and a seal, upper and lower piston stroke limiters, and the piston system comprises a piston with a flow channel narrowing at the inlet portion and a seal, a valve switch with radial channels, a compression spring located in the borehole of the cavity between the ledge of the piston and the lower limiter of its stroke, characterized in that the flow channel is made with a variable cross-section from tapering in the inlet section to smoothly expanding in the outlet section, while in the section of its maximum narrowing in the piston there is a bypass channel hydraulically communicating the flow channel with a piston cavity. 2. The valve according to claim 1, characterized in that the piston cavity is hydraulically disconnected from the annulus of the well by means of a seal installed in the upper part of the contactor above its channels. 3. The valve according to claim 1, characterized in that the smoothly expanding portion of the flow channel of the piston is made with a slope of 3-5 °. 4. The valve according to claim 1, characterized in that between the ledge of the piston and the piston stroke limiter above or below the spring mounted thrust bearing.

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