RU2256779C1 - Device for oil gas discharge from hole annuity - Google Patents

Abstract

FIELD: oil production industry, particularly for oil recovery from wells with the use of electric centrifugal pumps and to elevate oil with high gas content.

SUBSTANCE: device comprises flow string, electric centrifugal pumping plant, shutoff valves for well head, ejector device and check valve. Ejector device is arranged at well head and connected thereto by quick-releasable connector to create low-pressure area in receiving chamber. Pressure in receiving chamber is less than that in hole annuity. Check valve has lock pin to prevent plugging of check valve outlet at high flow rates, namely during oil gas delivery. Check valve seat is removable to provide inspection thereof when performing maintenance.

EFFECT: provision of optimal well operation, increased efficiency of oil gas discharge due to continuous pumping-out thereof, simplified assemblage and maintenance.

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Description

The invention relates to the field of oil and gas industry, in particular to the field of oil production from wells by electric centrifugal pumps, and allows the lifting of oil with a high gas content. The device is designed to optimize the operation of wells equipped with electric centrifugal pumps.

The prerequisites for creating the invention is the following: during the operation of wells by electric centrifugal pumps (ESP), an accumulation of oil gas occurs in the annulus of the well. The existing gas transfer valves make it possible to reduce the pressure in the annulus at best to linear. In some wells, where the length of the pipelines reaches significant values, the working linear pressure can reach 40 atm. This leads to unjustified loads on the tubing string (tubing), on a deflated installation of ESP and stuffing box.

From practice, a method is known for discharging oil gas from an annulus into the atmosphere by periodically opening a valve at the wellhead as pressure builds up and pressure rises to a critical value. This method has the following disadvantages:

1. The creation of gas contamination of the atmosphere and the associated fire and environmental hazards.

2. The need to attract workers to control pressure and to discharge oil gas due to the lack of necessary technical means.

Known lift gas-liquid mixture containing a tubing string, check valve, submersible pump, the discharge pipe of which is connected to the active nozzle of the jet apparatus with a receiving chamber, a mixing chamber and a diffuser [1].

The disadvantages of this lift is that the check valve is located in the tubing string, which leads to a decrease in the strength of the string, and in case of malfunctions, a complete lift of the downhole pumping equipment is necessary.

The closest in technical essence to the claimed one is the method of discharging gas from the annulus selected as a prototype, which includes creating a pressure in the tubing string below the pressure in the annulus and bypassing the gas while the in-line pump is operating from the annulus into the tubing cavity, and the tubing string is above the deep pump equipped with an ejector device, and the produced fluid is directed after leaving the deep pump through the nozzle of the ejector device into its mixing chamber [2].

This method has the following disadvantages:

1. For the installation of the device, it is necessary to have an underground well repair team.

2. The decrease in the strength of the tubing string due to the device in it check valve.

3. In the event of malfunctions associated with clogging of the device, a complete lift of the downhole pumping equipment is required.

4. Difficult quality sampling.

The aim of the invention is to increase the efficiency of the discharge of oil gas from the annulus due to continuous forced pumping, as well as simplified installation and maintenance of the inventive device.

This goal is achieved by the fact that in the receiving chamber of the device for discharging oil gas from the annulus creates a region of reduced pressure, compared with the pressure in the annulus, by equipping the wellhead with an ejector device.

It is also new that the ejector device is mounted on the wellhead using a quick-detachable detachable connection (BRS), and the check valve contains a locking pin that prevents clogging of the outlet of the check valve at high flow rates (supply) of oil gas.

The non-return valve seat is removable for inspection during repairs.

Patent research on the novelty of the claimed device was carried out according to the patent fund of NIS OAO Tatneft to a depth of 15 years. The research results showed that similar methods and devices used to optimize well operation, characterized by such a combination of essential features as the proposed device, are absent. Therefore, we can assume that the claimed technical solution has novelty and inventive step, and its industrial applicability is confirmed by a description of its implementation.

The drawing shows a device for discharging oil gas from the annulus.

The device is mounted on wellhead fittings using a quick-detachable detachable connection (BRS) and consists of an ejector device and a check valve. The ejector device includes a receiving chamber 1, a housing 2, an active nozzle 3, a passive nozzle 4, a diffuser 5, and a check valve 6 contains a valve seat 7 with a ball 8 and a locking pin 9.

The proposed device operates as follows.

The wellhead equipped with an ESP is equipped with an ejector device. During the operation of the ESP, the produced fluid, having a significant speed, is sent through the active nozzle 3, creates a reduced pressure zone in the receiving chamber 1, which causes the check valve 6 to open, as a result of which the ball 8 leaves the seat of the valve 7 and the oil gas from the annulus, mixing with the produced liquid is ejected through the diffuser 5 in line, providing continuous forced pumping. The non-return valve 6 prevents the production fluid from getting back into the well during ESP stops. The locking pin 9 does not allow the ball 8 to clog the outlet of the check valve 6 at high flow rates of petroleum gas. The seat 7 of the check valve 6 is made removable for inspection during repairs.

The advantages of the proposed device are:

- reducing the load on the tubing and ESP;

- reduction of annular pressure of oil gas, which allows to raise the dynamic level and, as a result, increase the productivity of the device;

- the effective use of oil gas pumped out from the annulus allows the use of oil gas to obtain more accurate measurements of the SKZh and GZU;

- a decrease in the viscosity of the product being pumped and, as a result of a decrease in viscosity, a decrease in energy costs and a decrease in the cost of travel demulsification;

- with certain technological and technical parameters it makes it possible to lower the annular pressure to atmospheric and lower, that is, it is possible to obtain negative values of the pressure in the annulus (vacuum effect);

- it is cheap to manufacture, and during installation and operation it eliminates the involvement of service departments and PRS teams.

The technical and economic advantage of the invention lies in the following: the device is technologically advanced, its use ensures operational reliability of the well and low implementation costs.

The device has been tested in the field of NGDU Prikamneft. The test results are positive.

Sources of information

1. RF patent No. 2157926, F 04 F 5/54 “Lift gas-liquid mixture”;

2. RF patent №2079636, Е 21 В 43/00 “Method of gas discharge from the annulus” - prototype.

Claims (1)

A device for discharging oil gas from the annulus containing a tubing string, an electric centrifugal pump installation, wellhead shutoff valves, an ejector device and a check valve, characterized in that the ejector device is located at the wellhead using a quick detachable connection (BRS) with the possibility creating a region of reduced pressure in the receiving chamber compared to the pressure in the annulus of the well, and the check valve contains a locking pin having zhnosti prevent 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.