RU2637683C1 - Device for release oil gas from annulus - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device comprises a tubing string, a pumping unit and a wellhead shut-off valve. There is also a discharge branch pipe. It is communicated with the tubing string. The device has an inlet and a check valve. This valve is provided with adjustable opening for providing required level of liquid in the annulus and communicated with the tubing string above the tubing string connection with the discharge branch pipe. Beyond the wellhead fittings said branch pipe is comprised of wellhead shut-off fittings upraised to a height not less than the inner diameter of discharge branch pipe. The oil gas release is provided through the tubing string with the use of appropriate stroke of sucker-rod pump plunger or stopping and subsequent starting of electric submersible pump.

EFFECT: simplification of the device and provision of possibility for using when operating with electric submersible pumps and submersible plunger-rod pumps.

2 cl, 3 dwg

Description

The invention relates to the oil and gas industry, in particular to pumping oil from wells with a high gas content.

Known deep-well pumping installation (patent PM RU No. 15209, IPC F04B 47/00, published in bulletin No. 27 of 09/27/2000), containing a submersible pump, an elevator string of tubing that goes into the flow line of the well, equipment for strapping of the mouth with valves for bleeding associated gas from the annulus to the flow line, while equipped with an additional gas valve placed on the elevator string under the equipment for strapping the mouth, with a spring-loaded plate.

The disadvantages of this installation are the narrow scope due to the inability to work in wells that open reservoirs with high reservoir pressure, since the valve will not be able to open to discharge gas into the lift string, and when placing the valve under the equipment for strapping, there is a high probability of flooding the valve from the annular space, which also eliminates the discharge of gas.

Known wellhead reinforcement (patent PM RU No. 60124, IPC EV 33/03, published in Bulletin No. 01 of January 10, 2007), including a pipe head with a flange and a lateral outlet, a pipe suspension with cylindrical channels for suspending tubing and establishing a locking body, while the flange of the pipe head is made with an internal thread for mounting the clamping ring, the cylindrical channel of the locking body has a narrowing in the form of a truncated cone, the conical narrowing has a bevel in the end part and is made with a lateral channel for communicating the annulus well bore with the internal cavity of the cylindrical channel of the suspension, while the shutoff body has cylindrical and conical parts, on the surface of which grooves are made for installing sealing rings, in addition, the squeeze spring of the shutoff body is placed in the cylindrical part of the channel, outside the zone of exposure to the well fluid.

The disadvantages of this valve are the narrow scope due to the inability to work in wells that open reservoirs with high reservoir pressure, because of the communication of the in-pipe space with the conical part of the shut-off element, and it will not be able to close, impairing the operation of pumping equipment, while the valves difficult to manufacture and maintain.

A device for discharging oil gas from the annulus (patent RU No. 2256779, IPC EV 43/00, publ. Bull. No. 20 dated 07/20/2005) containing a tubing string, an electric centrifugal pump installation, wellhead shutoff valves, an ejector device and a check valve, while the ejector device is located at the wellhead using a quick detachable connection (BRS) with the possibility of creating a region of reduced pressure in the receiving chamber compared to the pressure in the annulus of the well, and the check valve with It is holding a lock pin having a possibility of preventing clogging of the outlet check valve at high flow rates - feed gas, wherein the check valve seat is made detachable, with the audit during repairs.

The disadvantages of this device are the narrow scope due to work only with electric centrifugal pumps, the complexity of the manufacture and maintenance of individual for each well jet pumps.

The technical task of the invention is the creation of a simple and cheap to manufacture and maintain a device for discharging oil gas from the annulus with the ability to work with electric submersible pumps and submersible plunger pumps.

The technical problem is solved by a device for discharging oil gas from the annulus containing an elevator column, a pumping unit, wellhead shutoff valves, outlet products, a pipe connected to the elevator column, and a check valve.

What is new is that the check valve with adjustable opening to ensure the required level of fluid in the annulus is in communication with the elevator column above the connection of the elevator column with the outlet pipe, which, outside the wellhead, is made ascending from the wellhead shutoff valves to a height of not less than the inner diameter of the outlet pipe, moreover, the discharge of oil gas is provided through the lift column using the appropriate stroke of the plunger of the rod pump or stop and then start ska submersible pump.

It is also new that the outlet pipe is internally equipped with a gas outlet pipe ascending from the wellhead shutoff valve with a smaller angle than the outlet pipe, and connecting the upper zone of the outlet pipe near the wellhead shutoff valve with the lower zone of the outlet pipe after lifting.

In FIG. 1 shows a diagram of a device for discharging oil gas from an annulus.

In FIG. 2 shows a pipe in the ascending section from the well. In FIG. 3 shows a section AA, see FIG. one.

A device for discharging oil gas from the annulus 1 comprises an elevator column 2 (Fig. 1), a pumping unit (not shown in Fig. 1), equipped with a cable-rope 3 or rods 3, wellhead shut-off valves 4, outlet products 5 with an elevator column 2, and a non-return valve 6. A non-return valve 6 (of any known design: ball, poppet, cone, etc., the last two are not shown in Fig. 1) with adjustable opening to ensure the required level of fluid in the annulus 1 is communicated with elevator column d 2 above the connection of the elevator column 2 with the outlet pipe 5, which outside the wellhead 4 is made ascending at an angle α (Fig. 2) from the wellhead stop valves 4 (Fig. 1) to a height H (Fig. 2) of not less than the inner diameter D outlet pipe 5 (H≥D). The outlet pipe 5 (FIGS. 2 and 3) from the inside can be equipped with a gas outlet pipe 7, ascending from the wellhead shutoff valves 4 (FIG. 1) with a smaller angle β (FIG. 2) than the outlet pipe 5 (α> β), and connecting the upper zone 8 of the discharge pipe 5 near the wellhead shutoff valves 4 (Fig. 1) with the lower zone 9 (Fig. 2) of the discharge pipe 5 after lifting. Technological connections and seals that do not affect the principle of operation of the device, in FIG. 1-3 are not shown or shown, but not numbered.

A device for discharging oil gas from the annulus works as follows.

After hydrodynamic studies of the properties of the reservoir (not shown in Fig. 1), the closing force of the check valve 6 (Fig. 1) is adjusted (for example, by adjusting the valve preload by the spring 10) to ensure the fluid level in the annulus 1 (determined empirically). After the elevator string 2 with the valve 6 is lowered into the well and the pump unit with the cable 3 or rods 3 is installed, the mouth is sealed with wellhead fittings 4, ensuring the outlet pipe 5 communicates with the elevator column 2. The pump unit is put into operation, during which the formation products rise to the surface , and is selected at the outlet pipe 5.

When a sucker rod pump is used as a pump unit during the plunger stroke (not shown in FIG. 1) together with rods 3 down due to a non-instantaneous closing of the suction valve (not shown in FIG. 1), the liquid level in the lift column 2 slightly decreases creating there is a vacuum inside, and the oil gas accumulating in the annulus 1 creates an overpressure above, as a result, the check valve 6 opens and an excess amount of gas (due to the adjustable valve 6) from the annulus 1 enters elevator column 2. During the course of the rods 3 with the plunger upward, an excess pressure is created in the elevator column 2, displacing gas from the upper part of the elevator column 1 to the outlet pipe 5 together with the formation products rising along the elevator column 1 and further, mixing with the well production (three-phase mixture - oil, gas and water), enters the flow line (not shown in Fig. 1).

When using an electric submersible pump (for example, a screw or an electric centrifugal pump) as the pump installation, during its operation, an excess pressure is created inside the lift column 2, which shuts off the valve 6, and oil gas accumulates in the annulus 1. To discharge gas after a predetermined time (determined by hydrodynamic studies to prevent a decrease in the liquid level under the action of accumulated gas in the annulus 1 below the critical one), the electric cable is stopped through the cable-rope 3, stopping the pump. The liquid level in the elevator column will begin to decrease, since the protective valve (not shown in Fig. 1) of the pump does not close instantly, creating a vacuum inside, and the oil gas accumulating in the annulus 1 creates an overpressure above, as a result, the non-return valve 6 opens and the excess the amount of gas (due to the adjustable valve 6) from the annulus 1 enters the elevator column 2. When an electric current is supplied through the cable rope 3, the pump starts, an excess pressure is created which displaces the gas from rhney part of the production tubing 2 to a discharge pipe 5, together with the formation of products rising production tubing 2, and further, mixing with the well production (three-phase mixture - oil, gas and water) enters the flow line.

Due to the fact that the outlet pipe 5 outside the wellhead fittings 4 is made ascending at an angle α (Fig. 2) from the wellhead shutoff valves 4 (Fig. 1) to a height N (Fig. 2) of at least an inner diameter D of the outlet pipe 5 ( H D D), the gas is immediately diverted from the wellhead 4, since it is less in density than the density of the production of the formation, thereby eliminating gas leakage from the outlet 5 when the plunger with rods 3 moves down or when the electric submersible pump stops. Since the inlet of the outlet pipe 5 is constantly in the reservoir fluid (and the fluid is practically not compressible) due to the emergence of gas, the efficiency of gas extraction from the annulus 1 of the lift column 2 does not decrease.

When a large amount of gas is formed, this is especially true when using an electric submersible pump as a pumping unit, it is necessary to break the gas when pumping through the outlet pipe 5 into small bubbles in order to exclude the creation of a “water seal” when pumping formation products along the flow line. To do this, the outlet pipe 5 (Fig. 2 and 3) from the inside is additionally equipped with a gas outlet pipe 7, ascending from the wellhead shutoff valves 4 (Fig. 1) with a smaller angle β (Fig. 2) than the outlet pipe 5 (α> β), and connecting the upper zone 8 of the discharge pipe 5 near the wellhead shutoff valves 4 (Fig. 1) with the lower zone 9 (Fig. 2) of the discharge pipe 5 after lifting. Thus, gas from zone 8 enters zone 9 through a gas outlet pipe 7 due to the natural supply (Archimedes force) of gas under the formation production stream, which leads to the division of the gas stream into smaller bubbles when floating through the liquid (formation production).

Since the non-return valve 6 (Fig. 1) is located above the connection of the elevator column 2 with the outlet pipe 5, the interaction of the valve 6 with the production of the formation is excluded and, as a result, it will not clog and deposit paraffins and asphaltenes on it. The result is simplified maintenance of the device as a whole.

The absence of a large number of complex elements also simplifies the manufacture of the device and, as a result, reduces the cost of the whole.

The proposed device for discharging oil gas from the annulus is simple and cheap to manufacture and maintain, and is made with the ability to work with electric submersible pumps and submersible plunger pumps.

Claims (2)

1. A device for discharging oil gas from the annulus, comprising an elevator column, a pumping unit, wellhead shutoff valves, product outlet pipes connected to the elevator column, and a non-return valve, characterized in that the non-return valve with adjustable opening to provide the required liquid level in the annulus is in communication with the elevator column above the connection of the elevator column with the outlet pipe, which is made upstream of the wellhead valves from the wellhead valves height of at least the inner diameter of the transfer tube, wherein the discharge gas is provided through the tubing using an appropriate stroke of the plunger pump or sucker-rod stop and then start the submersible pump. 2. A device for discharging oil gas from the annulus according to claim 1, characterized in that the outlet pipe is internally provided with a gas outlet pipe ascending from the wellhead shutoff valve with a smaller angle than the outlet pipe and connecting the upper zone of the outlet pipe near the wellhead shutoff valve with the lower zone of the outlet pipe after lifting.

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