RU2307249C1 - Device for well oil production rate measurement - Google Patents

Abstract

FIELD: oil production, particularly to estimate oil and gas-condensate wall (independent well or well cluster) production rate in pressure-sealed gathering facilities.

SUBSTANCE: device comprises measuring vessel, gas pipeline and well product inlet and outlet pipes connected to measuring vessel. Measuring vessel is at least partly formed of tube. Upper measuring vessel part is shaped as tube or truncated cone, wherein minor truncated cone base diameter is equal to tube diameter. Partition with calibrated orifice or orifices and with orifice to connect gas pipeline located inside measuring vessel is formed in lower measuring vessel part and extends transversally to tube axis. Gas pipeline inlet is located in upper measuring vessel part. Outlet thereof is downstream of partition. Well product inlet pipe is connected to upper measuring vessel part and is transversal or tangential thereto. Well product outlet pipe is connected to lower measuring vessel part. Measuring vessel and gas pipeline are coaxial with each other or arranged so that measuring vessel and gas pipeline axes are parallel one to another. Located inside gas pipeline are measuring means, differential pressure sensor, as well as temperature and static pressure sensors. Measuring means is made, for instance, as nozzle. Differential pressure sensor has the first inlet connected to measuring means and the second inlet linked to gas pipeline over measuring means. Two differential pressure sensors are located inside measuring vessel over partition. The first inlets of the differential pressure sensors are located near partition and the second ones are arranged at different heights. In particular cases partition with calibrated orifice and measuring means may be formed of hard-alloy material. Means to close gas pipeline inlet orifice, for instance gate or electromechanically driven valve, may be formed in upper measuring vessel part. Static pressure sensor may be located over well product inlet pipe. Inlet of one differential pressure sensors located inside measuring vessel may be carried by float.

EFFECT: increased measurement accuracy and decreased measurement time, improved operational reliability and simplified usage.

5 cl, 1 dwg

Description

The invention relates to oil production and can be used for operational accounting of production rates of oil and gas condensate wells (both individual and well) in pressurized collection systems.

A known device for measuring the flow rate of oil wells, containing a measuring tank, a gas pipeline and nozzles for supplying and withdrawing wells, in which a device for determining the time of filling a measuring tank of a fixed volume with partially separated well products with a gas pipeline open to the collector and a closed branch pipe devices for measuring excess pressure, temperature, rate of displacement of the contents of the container after closing the gas the pipeline and the opening of the branch pipe for the production of wells. / Certificate for utility model No. 22179, MKI ⁷ Е21В 47/10, publ. 2002 Bul. No. 7 /.

The disadvantages of the known device are:

- low accuracy and instability of measurements with increased foaming and high debate wells;

- significant measurement time due to the need to displace the contents of the container after closing the gas line;

- the complexity of operation in the winter, as there is a high probability of freezing of cranes at high water cuts or idle wells.

The closest in technical essence and the achieved result to the claimed object is a device for measuring the production rate of oil wells, containing a measuring tank, a gas pipeline and nozzles for supplying and withdrawing wells, in which the filling of the measuring tank of a calibrated volume is performed with the gas pipeline open to the collector and closed branch pipe for production of wells, devices for measuring hydrostatic pressure at a known height of the liquid column, overpressure Nia, temperature, contents of the container after closing the displacement velocity of the gas pipeline and the opening of the nozzle outlet of well products at the collector, during filling of the measuring vessel and the device measuring the liquid column height and hydrostatic pressure. / RF patent №2220282, IPC ⁷ ЕВВ 47/10, publ. 12/27/2003. Bull. No. 36 /.

The disadvantages of this method are:

- low accuracy and instability of measurements, due to the need to withstand the production of wells contained in the measuring tank, to a state of complete absence of bubble gas and foam subsidence;

- significant time from measurements due to the need for such exposure;

- the complexity of operation in the winter, as there is a high probability of freezing of cranes at high water cuts or idle wells.

- the complexity of management due to the need to open and close the gas pipeline and pipe branch of the production of wells to the reservoir.

The present invention is aimed at improving the accuracy of measurements and reducing their time, improving reliability and ease of use.

This is achieved by the fact that in the device for measuring the production rate of oil wells containing a measuring tank, a gas pipeline and connecting pipes for supplying and removing wells, connected to the measuring tank, the measuring tank is completely or partially made of pipe, the upper part of the measuring tank is made in the form of a pipe or a truncated cone, and the smaller diameter of the truncated cone is equal to the diameter of the pipe, in the lower part of the measuring capacity perpendicular to the axis of the pipe made a partition with caliber With a hole (or holes) and a hole for the gas pipeline, the gas pipeline is located inside the measuring vessel, the gas pipeline entering at the top of the measuring vessel and the outlet after the baffle, the well supply pipe is connected directly or tangentially to the upper part of the measuring vessel and the outlet pipe for the production of wells is connected to the lower part of the measuring capacity, the axis of the measuring capacity and the gas pipeline are coaxial or parallel, inside the gas about the pipeline there is a measuring device made, for example, in the form of a nozzle, there is a differential pressure sensor inside the gas pipeline, one input of which is connected to the measuring device, and the other to the gas pipeline above the measuring device, as well as temperature and static pressure sensors, inside the measuring above the bulkhead there are two differential pressure sensors, for which, both, one inlet is located near the bulkhead and the other at different heights. In addition, in some cases, the calibrated holes and the measuring device can be made of carbide material. In addition, in some cases, in the upper part of the measuring capacitance, a device can be made to block the inlet to the gas pipeline, for example, a valve or valve with an electromechanical actuator. In addition, in some cases, a static pressure sensor may be located in the measuring capacitance above the nozzle for supplying well production. In addition, in some cases, the input of one of the differential pressure sensors located inside the measuring vessel may be mounted on the float.

Well production is a water-oil and gas mixture consisting of liquid and gas phases. The liquid phase - water-oil emulsion - consists of two immiscible components - produced water and oil.

It is known that the gas density ρ _g according to the Mendeleev-Clapeyron equation is

where R _{article, g} - static gas pressure, R _g - specific gas constant, T _g - gas temperature.

The density of the reservoir fluid (oil-water emulsion) is

where ρ _W , ρ _in and ρ _n - respectively, the density of the reservoir fluid, produced water and oil; n _in - water cut (volume fraction of water per unit volume of reservoir fluid).

It is known that the pressure drop ΔР _{Ж, h} along the height h _Ж between two points, measured using a differential pressure sensor, the inputs of which are located at these points, is

where g is the acceleration of gravity.

From relations (2) and (3), after simple transformations, we obtain the formula for determining the water cut

It is known that the volumetric flow rate of liquid Q _W through an opening of area F is

where α is the flow coefficient, N _W is the height of the liquid column.

The height of the liquid column in expression (5) is determined from the formula (3)

where ΔP _{W, N} - pressure drop at the height of the liquid column H _W

Thus, if using a differential sensor, one input of which is located at the septum, and the other is above the upper surface of the liquid in the measuring tank, we measure the pressure drop ΔP _{W, N} , liquid column height; and with the known density of the liquid (2) water cut (4) we find the height of the liquid column (6) in the measuring tank. Then, using (5), we determine the volumetric flow rate of the liquid.

The dynamic gas pressure is

where w _g is the gas velocity, ΔP _g is the pressure drop of the gas.

The gas volumetric flow rate is equal to the product of its velocity and the cross-sectional area of the gas pipeline F _g . Taking into account (1) and (7), the indicated expression takes the form

Then we find the reduced gas factor as the ratio of the volumetric flow rate of gas (3) to the volumetric flow rate of oil (2) and (5)

After bringing the reduced gas factor to normal physical conditions, we obtain the gas factor.

The manufacture of the measuring tank in whole or in part from the pipe allows to simplify its manufacture.

The execution of the upper part of the measuring capacity in the form of a truncated cone, and the smaller diameter of the truncated cone is equal to the diameter of the pipe, allows you to organize an increase in the angular frequency of rotation with a decrease in the radius of rotation of the incoming water-oil and gas mixture, which ensures an increase in gas evolution.

Performing at the bottom of the measuring capacitance perpendicular to the axis of the pipe wall of the partition with a calibrated hole (or holes) and a hole for the gas pipeline, allows you to organize the determination of the volumetric flow rate of the liquid and its water cut in that part of the measuring tank, which is located above the partition.

Performing a partition with a calibrated hole allows you to determine the volumetric flow rate of the liquid (5).

The location of the gas pipeline inside the measuring tank allows to reduce the size of the device and the introduced distortion.

The entrance to the gas pipeline in the upper part of the measuring tank allows you to reduce the time before the start of measurement of gas parameters.

The output of the gas pipeline after the partition allows you to remove the gas and liquid phases of well production from the separation tank at the same time, which reduces the dimensions of the device and simplifies its manufacture.

The connection of the pipe for supplying the production of wells directly or tangentially to the upper part of the measuring tank allows the oil-gas mixture to be separated into gas and liquid under the influence of gravitational and, in the case of tangential input, centrifugal forces, which reduces the size of the device and increases its efficiency.

The connection of the branch pipe for the production of wells to the lower part of the measuring tank (below the baffle) allows the liquid and gas phases of the production of wells to be diverted simultaneously from it.

The execution of the axes of the measuring capacitance and the gas pipeline coaxial or parallel can improve the accuracy of the measurements by reducing the introduced disturbances.

The location inside the gas pipeline of the measuring device, made, for example, in the form of a nozzle, improves the accuracy of measuring the volumetric gas flow.

The location inside the gas pipeline of the differential pressure sensor, one input of which is connected to the measuring device, and the other to the gas pipe above the measuring device, allows you to measure the dynamic gas pressure (7), necessary to determine the volumetric gas flow (8).

The location of the gas temperature and static gas pressure sensors makes it possible to determine the gas density (1) and to ensure the determination of the gas factor under normal physical conditions.

The location inside the measuring tank above the partition of two differential pressure sensors, for which, both, one inlet is located near the partition and the other at different heights, allows using formulas (2) ... (6) to determine the volumetric flow rate and water cut.

The implementation of a partition with calibrated holes and a measuring device made of carbide material allows to reduce their wear during operation, for example, due to the influence of abrasive particles, which improves measurement accuracy and increases the life of the device.

The implementation in the upper part of the measuring capacity of the device for closing the inlet to the gas pipeline, for example, a valve or valve with an electromechanical actuator, allows you to periodically clean, for example, once an hour, calibrated openings, since with a closed gas pipeline the entire supplied oil-gas mixture will pass through the calibrated openings . This provides improved measurement accuracy by eliminating contamination.

The location of the static pressure sensor in the measuring tank above the inlet pipe for the production of wells makes it possible to take into account the influence of the static gas pressure on the flow coefficient from relation (5), which makes it possible to increase the accuracy of measuring the volumetric liquid flow.

The installation of the input of one of the differential pressure sensors located inside the measuring vessel on the float reduces the effect of static gas pressure on the accuracy of measuring the volumetric flow rate of the liquid.

A device for measuring the production rate of oil wells is shown in Fig.1.

A device for measuring the production rate of wells consists of a measuring tank 1 made in the form of a pipe. In the lower part of the measuring tank 1 there is a partition 2 with calibrated holes 3. Inside the measuring tank 1 there is a gas pipeline 4. To it are also connected nozzles for supply 5 and outlet 6 of well products. Inside the measuring vessel 1 above the partition 2, the inputs of the differential pressure sensors 7 and 8 are installed. The measuring device 9, made in the form of a nozzle, is located in the gas pipeline 4. One input of the differential pressure sensor 10 is located in the critical (smallest) section of the measuring device 9, and the other is above him. In the gas pipeline 4 is also installed the input of the device 11 for measuring the static gas pressure and gas temperature. At the upper end of the measuring tank 1 is a device 12 for blocking the inlet to the gas pipeline 4.

A device for measuring the production rate of wells works as follows. Prior to the test, the following shall be measured:

- oil density;

- density of water;

- specific gas constant;

- flow rate;

- area of the calibrated hole;

- cross-sectional area of the measuring device 10;

- the height between the inputs of the differential pressure sensor 7.

Then, in the measuring tank 1, made in the form of a pipe, the production of the well (s) —the water-oil and gas mixture — enters the supply pipe 5. Under the influence of gravity and centrifugal force, the oil-gas mixture is divided into liquid (oil-water emulsion) and gas. The liquid forms a film and flows down the inner surface of the measuring tank 1 to a column of liquid. In this case, the gas dissolved in the liquid, gas from the liquid, is released. Then the liquid flows out through calibrated openings 3 in the partition 2 to the lower part of the measuring tank 1, gas through a gas pipeline 4 also enters the lower part of the measuring tank 1, from where liquid and gas are discharged through the branch pipe 6, in the process a liquid column is installed in the measuring tank 1 constant height N. The pressure drops ΔР _{ж, h} and ΔР _{ж, H} are measured in the measuring tank 1 using two differential pressure sensors 7 and 8. In the gas pipeline 4, the dynamic gas pressure is measured using di the differential pressure sensor 10 and the static gas pressure and gas temperature using the device 11. The information measured by the differential pressure sensors 7, 8 and 10 and the static pressure and temperature 11 is stored and stored in the controller or fed to a computing unit, such as a laptop.

The calculations are performed in the following sequence:

1) water cut is determined by the formula (4);

2) the formula (2) determines the density of the liquid;

3) the formula (6) determines the height of the liquid column in the measuring tank 1;

4) the formula (5) determines the volumetric flow rate of the liquid;

5) gas density is determined by formula (1);

6) the volumetric gas flow rate is determined by formula (8);

7) the reduced gas factor is determined by the formula (9);

8) recalculation into the gas factor under normal physical conditions.

After some time, for example, an hour, using the device 12, close the inlet of the gas pipeline 4. All incoming liquid and gas begin to pass through the calibrated openings 3 and clean them of contamination and deposits.

Thus, the inventive device for measuring the production rate of oil wells can improve the accuracy of measurements, and reduce their time and simplify use.

Claims (5)

1. A device for measuring the production rate of oil wells, containing a measuring tank, a gas pipeline and connected to the measuring tank nozzles for supplying and removing wells, characterized in that the measuring tank is fully or partially made of pipe, the upper part of the measuring tank is made in the form of a pipe or truncated cone, and the smaller diameter of the truncated cone is equal to the diameter of the pipe, in the lower part of the measuring capacity perpendicular to the axis of the pipe a partition is made with a calibrated hole with a hole (or holes) and a hole for the gas pipeline, the gas pipeline is located inside the measuring container, the entrance to the gas pipeline being made at the top of the measuring tank, and the outlet after the baffle, the pipe for supplying well products is connected directly or tangentially to the upper part of the measuring tank, and the outlet pipe for the production of wells is connected to the lower part of the measuring capacity, the measuring capacity and the gas pipeline are coaxial or their axes are parallel, inside the gas pipe water there is a measuring device made, for example, in the form of a nozzle, there is a differential pressure sensor inside the gas pipeline, one input of which is connected to the measuring device, and the other to the gas pipeline above the measuring device, as well as temperature and static pressure sensors, inside the measuring tank above the partition there are two differential pressure sensors, in which one inlet is located near the partition and the other at different heights. 2. The device for measuring the production rate of oil wells according to claim 1, characterized in that the partition with calibrated holes and the measuring device are made of carbide material. 3. The device for measuring the production rate of oil wells according to claim 1 or 2, characterized in that in the upper part of the measuring tank there is a device for blocking the inlet to the gas pipeline, for example, a valve or valve with an electromechanical actuator. 4. The device for measuring the production rate of oil wells according to claim 3, characterized in that in the measuring capacitance above the pipe for supplying the production of wells is a static pressure sensor. 5. The device for measuring the production rate of oil wells according to claim 3, characterized in that the input of one of the differential pressure sensors located inside the measuring tank is mounted on the float.