SU991030A1 - Cast-lift valve - Google Patents

Description

(54) GASLIFT VALVE

one

. . The invention relates to the oil industry and can be used to achieve oil using a gas-lift method.

Known gas-lift valve, comprising a housing with channels, a fitting placed therein, seats, a locking element in bushings, a rod and springs II.

A disadvantage of the known device is the inability of the unregulated regulation of the gas supply.

Closest to the invention in terms of its technical essence and achievable results is a gas-lift valve, comprising a housing with radial holes, a rod with an axial channel, a bellows filled with compressed 1st, gas, seals and a shut-off unit {2.

The disadvantages of this device are the low accuracy of maintaining a given mode of selection of production of a well.

The aim of the invention is to improve the accuracy of maintaining a given mode of production selection of a well.

To achieve this goal, a gas-lift valve comprising a housing with radial holes, a stem with an axial channel, billet filled with compressed gas, reinforcements, and a shut-off unit, a shut-off unit in the form of a piston with a channel for communicating the axial shaft channel with the radial holes in the housing .

The drawing shows a gas lift valve.

The gas-lift valve includes a housing 1, a valve 2 installed therein for charging the bellows chamber 3. Inside the bellows chamber 3 is a rod with an axial channel 4 for the passage of gas, the upper end of which is connected with the bellows 5 and the piston 6 is radial With the bore 7. At this point, the piston has a channel 8, which can communicate with the radial bore 7 in the housing 1. The piston 6 has a seal 9 to prevent the passage of gas. A filter 10 is installed below the piston to prevent MexnpHMecdi from entering the piston.

The gas lift valve works as follows. .

Before the valve is lowered into the well, the bellows chamber is filled with compressed gas under the design pressure.

After the valve is lowered into the well, the hydrostatic pressure in the lift string acts under the piston 6 and moves it up, as the piston 6 communicates from below with the lift pipes, and the channel 8 of the piston 6 is aligned with the hole 7 and the valve opens. The injected gas from the annular space flows through the bellows neck 5, channel 4 of the stem, passes through channel 8 of the piston 6, holes 7 in the housing 1 and enters the lift pipes, airing the liquid in them), after which the well begins to work.

The balance of forces acting on the piston, has the form

RSNL-MSS RFC RT P

4-5 CMA 4

where is the pressure in the bellows chamber;

snl

-the area of the base of the bellows

Sil of its average diameter

- outer diameter of axial shaft stockpile, m;

- the area of the cross section of the piston channel,

- pressure in lift pipes. opposite the valve;

- working gas pressure in the annulus;

. nominal space and piston area.

If the pressure of the injected gas rises in the system (when the well group stops for repairs), the gas flow acts on the surface of the channel 8 of the piston 6 and moves it down. The piston 6 covers the opening 7 in the housing 1, i.e., reduces its flow area, thereby reducing the amount of gas passing through this opening 7. Thus, a constant pressure in the elevator pipes at the valve is maintained and the gas flow is maintained.

The balance of forces acting on the piston 6, has the form

RSML SML RR P RT P; RR - RR-Rid /

where R. is gas overpressure, I act

Its

a piston when a group of wells is stopped for repairs. When drilling downhole pressure leads to a decrease in well production (for example, during the deposition of paraffin and salts 8 lifting pipes and flow lines),

The overpressure in the lift pipes acts on the piston 6 from bottom to top and the piston rises and the opening 7 opens slightly to a greater extent than before the pressure in the lift pipes rises. This leads to an increase in the gas flow rate and a decrease (in combination with the specific gravity of the fluid being injected, and, consequently, to a decrease in the bottomhole pressure, to ensure the set flow rate of the fluid.

The balance of forces acting on the piston 6 has the form

   V -n

MN

S

, R.- - overpressure in lift

Where

pipes at the valve.

Thus, when the well is operated, the piston 6 acts from below on the hydrodynamic pressure of the aerated liquid, which forces to completely open the opening 7, and on the top the closing pressure created by compressed nitrogen in the bellows chamber 3, and the pressure of the flow of the pressurized gas acting on the surface of the channel 4. The resulting forces keep the piston at such a distance that the amount of gas required for the established operation of the well passes through the resulting area of the aperture 7, this allows aeration of the fluid in pipes to such an extent that creates a dynamic pressure gradient corresponding to the minimum flow rate of the working agent. The piston 6, in the course of well operation, responds to changes in pipe and annular pressure — oscillating movements, thereby adjusting the degree of opening of the opening 7 and the flow rate of the injected gas.

The gas-lift valve allows the setting of the flow rate of the working agent during changes in pressure in the gas supply system, as well as stabilizing the mode of operation of the well with changes in the bottomhole pressure.

Claims (2)

1. USSR author's certificate No. 578444, E 21 B 34/06, 1974. cl. 2. US patent GR 3888273, cl. 137-155 1975 (prototype).