RU2474808C1 - Device for determining volume fractions of water and oil in taken samples from flow of product of oil well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device consists of an automatic flow switch controlling the product flow direction in the oil well inside the device, a valve cutting off the sample to the sampling tank, a pressure sensor, a temperature sensor, a heater, a control unit and a level gauge, as per the readings of which volume fractions of water and oil in samples taken from flow of product of the oil well are determined.

EFFECT: improvement of determination accuracy of volume fractions of water and oil in the samples taken from oil well product flow owing to automatic multiple sampling, heating of samples, clarification and measurement of level of liquid-gas and water-oil media boundary lines.

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Description

I. The technical field to which the invention relates.

The invention relates to oil production and can be used to determine the volume fractions of water and oil in the selected samples from the flow of the oil well.

II. State of the art

Analogs of the invention:

1. The method and device for measuring the concentration of water in the oil-gas mixture (patent RU 2249204 C2).

The method involves sampling, sedimentation, measuring hydrostatic pressure and the transit time of an ultrasonic pulse through a layer of settled water. This measurement method is based on a pressure differential depending on the density and viscosity of the medium.

The disadvantages of the analogue:

- the influence of the density and viscosity of the medium on the pressure drop reduces the accuracy of the measurement;

- high technical complexity and cost;

- sampling for determining the concentration of water in the oil-gas mixture is performed in manual mode, which significantly increases the complexity of this device during operation and reduces the accuracy of the measurements.

III. Disclosure of invention

There is no analogue capable of automatically taking samples from an oil well stream repeatedly and determining the volume fractions of water and oil in selected samples directly at the place of operation.

To date, the task of determining the volume fractions of water and oil in the production of an oil well is solved in the following way: a sample is taken from the flow of production of an oil well and, in laboratory conditions, the volume fractions of water and oil are determined. Based on the results obtained, conclusions are drawn about the water and oil content in the production of this oil well.

The presented analogue 1 is capable of determining only the concentration of water in the oil-gas mixture selected from the flow of an oil well with a high measurement error.

The presented device has significant advantages:

- multiple sampling takes place automatically in the field directly;

- the determination of the volume fractions of water and oil in each sample taken is made directly at the place of operation, which in turn eliminates the cost of transportation, identification and storage of the samples taken, if the determination of the volume fractions of water and oil in the selected samples would be carried out in the laboratory.

To disclose the invention, consider FIG. 2. It shows the full cycle of the device, consisting of three automatic modes:

a) sampling from an oil well product stream;

b) determination of the volume fractions of water and oil in the selected sample;

c) the displacement of the selected sample in the flow of oil wells.

In the device connected at the place of operation, the flow of oil well products has the following direction: inlet pipe 7, check valve 4, sampling tank 1, automatic flow switch 3, output pipe 8.

Sampling from the oil well stream (see fragment a) of Fig. 2) occurs after the automatic flow switch 3 redirects the flow of oil well production in the direction: inlet pipe 7, automatic flow switch 3 and output pipe 8. Next, the check valves will work 4, which cuts off the sample in the sampling tank 1, and gas 5, which equalizes the pressure inside the sampling tank 1 and the flow of oil production.

In this case, the device will switch to the mode of determining the volume fractions of water and oil in the selected sample (see fragment b) of figure 2), which consists of the following steps:

- heating the selected sample in the container for sampling;

- sedimentation of the heated selected sample until separation;

- measuring the relative position of the liquid-gas and water-oil interface lines and determining the volume fractions of water and oil in the selected sample from the oil well stream.

After the determined volume fractions of water and oil in the selected sample, the device will switch to the mode of displacing the selected sample in the flow of oil wells (see fragment b) of figure 2). This will happen after the automatic flow switch 3 redirects the flow of oil well production in the following direction: inlet pipe 7, check valve 4, sampling tank 1, automatic flow switch 3, output pipe 8. The flow of oil production will displace the previously selected sample from the sampling tank and the device will be ready for a new cycle of determining the volume fractions of water and oil in the selected samples from the flow of oil well production.

Thus, due to the fact that the present invention uses an automatic flow switch and valves (return and gas), automatic multiple sampling is carried out from the oil well product stream and the volume fractions of water and oil in the selected samples from the oil well product stream are determined.

VI. Brief Description of the Drawings

Figure 1 shows:

1 - capacity for sampling;

2 - a level gauge measuring the level of the interface between liquid-gas and water-oil;

3 - automatic flow switch that controls the flow of oil well products inside the device;

4 - check valve, cutting off samples in the tank for sampling 1;

5 - gas valve, designed to equalize the pressure inside the tank for sampling 1 and preventing the penetration of the flow of oil production into the tank for sampling 1;

6 - heater, producing heating of the sample;

7 - inlet pipe designed to enter the flow of oil well products into the device;

8 - output pipe, designed to output the flow of oil wells from the device;

9 is a control unit for processing data received from the level gauge 2, temperature sensor 10, pressure sensor 11, and also controls the operation of the automatic flow switch 3 and heater 6;

10 is a temperature sensor designed to monitor the temperature of a sample taken from an oil well stream;

11 is a pressure sensor designed to control the pressure in the sampling tank.

Figure 2 shows the automatic modes of the device:

a) sampling from an oil well product stream;

b) determination of the volume fractions of water and oil in the selected sample;

c) the displacement of the selected sample in the flow of oil wells.

Positions 1 through 11 are described in the commentary to FIG. 1.

12 - direction of the flow of oil well products inside the device;

13 - water exfoliated during heating and sedimentation of the selected sample;

14 - oil exfoliated during heating and sedimentation of the sample;

15 - free petroleum gas released during the heating and sedimentation of the selected sample.

V. The implementation of the invention

In the presentation of section III (Disclosure of the invention) the construction and principle of operation of the invention are described in detail.

Claims (1)

A device for determining the volumetric fractions of water and oil in the selected samples from the flow of oil wells, consisting of a tank for sampling, a level gauge, pressure sensor, temperature sensor, heater and control unit, characterized in that, in order to improve the accuracy of determining the volumetric fractions of water and oil in the selected samples from the oil well’s product stream, an automatic flow switch is introduced into it, which controls the oil well product flow inside the device, and valves that allow production be automatic multiple sampling from the flow of oil well production directly on site.

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