RU2225507C1 - Device for measuring water percentage in oil in wells - Google Patents

Abstract

FIELD: oil deposits exploiting. SUBSTANCE: device has measuring tank and pressure sensor. Measuring tank is separated into measuring and draining enclosures by a dividing wall. In the upper part of measuring tank a joining pipe for venting draining enclosure with gas is made and connected to lower part of draining enclosure by means of pipe. EFFECT: simplified construction and increased reliability of device. 1 dwg

Description

The invention relates to the field of development and operation of oil fields, in particular to the measurement of water cut in oil wells.

The most common method for determining water cut in wells used in oil fields is to periodically take samples and then analyze them in a chemical laboratory. This method is based on the fact that, with a known volume, the mass of oil-water liquid is directly proportional to its density. The main disadvantage of this method is the impossibility of its automation. There are other methods of measuring fluid density: float, hydrostatic, vibrational, radioactive, etc. [1], which are not used in the oil industry due to specific production conditions;

- object of measurement - a water-oil liquid with a gas dissolved in it is very complex;

- field conditions for the operation of such a device.

The prior art well-known bellows densitometer with a unified pneumatic transducer type ПЖС-П [1]. This device measures the hydrostatic pressure of a liquid column at a constant height. The liquid contained in the measuring tank acts on the measuring bellows spaced in height and connected by a beam. The bellows are isolated from the liquid and air is supplied into them. Hydrostatic fluid pressure leads to uneven deformation of the measuring bellows. This movement of the bellows is transmitted to the beam connecting the measuring bellows, and then through a system of levers using a standardized pneumatic transducer to the piezometric pressure sensor.

The disadvantages of the known device [1] include:

- the complexity of the device, requiring qualified maintenance personnel and excluding work in the field;

- the presence of compressed air, which requires additional costs;

- the complexity of the measurement object, the continuous evolution of the gas phase in a closed volume of the measuring capacity.

The closest analogue of the claimed is a device for measuring water cut in oil, containing a measuring capacitance and a sensor for measuring pressure [2].

The main disadvantage of the device [2] is its complexity.

The objective of the invention is to simplify a device for automatically measuring the water cut of oil while increasing the reliability of its operation in oil fields.

The task is achieved in that the principle of operation of the device is directly related to the operation of an automated group metering unit (AGZU), for example, of the "Sputnik AM-40" type, used to measure the flow rate of wells in oil fields [3]. It should be noted that the work of the satellite type "Sputnik A" does not provide for the measurement of another parameter significant for the development of an oil field - water cut. The production rate of oil wells using AGZU is carried out by briefly passing the fluid accumulated in the separator through a turbine flow meter. The cyclic method for measuring the flow rate of oil producing wells ensures that the fluid flow passes through the meter in a narrow range of flow rates, which allows measuring the flow rate of wells in a wide range. The oil-water liquid that has passed through the meter enters the measuring capacity of the device, which is divided by a partition into two chambers, and flows from one chamber to another. The passage of fluid through the meter and device occurs when the gas valve is closed. At the end of the flow measurement cycle with the aid of a gas condensate generator, the measuring line is blocked by the flow regulator and a liquid column remains in the measuring chamber of the device, the height of which is determined by the height of the partition. The completion of the flow measurement cycle corresponds to the opening of the gas valve, and gas is supplied to the upper part of the device from the separator AGZU, which blows the drain chamber of the device. The hydrostatic pressure of a liquid column is measured using a differential pressure gauge when the flow regulator is closed.

A comparison of the proposed solutions with other technical solutions shows that the measurement of the hydrostatic pressure of the liquid along the height of its column is known. However, when using the inventive device with AGZU, the principle of which is based on the accumulation of liquid in the separator and then passing it through the meter, it is possible to measure the hydrostatic pressure after passing another portion of the oil-water liquid. Strictly fixed height of the liquid column improves the reliability of determining the density. This allows us to conclude that the technical solution meets the criterion of "significant differences".

The technical essence of the invention is illustrated by the circuit diagram of the device shown in the drawing.

A device for measuring water cut in oil in wells contains a measuring tank 1, divided by a partition 2 into two chambers: a measuring chamber 3 and a drain 4. The measuring chamber has two nozzles 5 and 6 for attaching a pressure sensor 7. At the top of the device’s tank there is a nozzle 8 connected by a tube 9 with the bottom of the drain chamber.

The device operates as follows. The next portion of the water-oil liquid comes from the AGZU into the measuring chamber 3 of the device and flows through the partition 2 into the drain chamber 4 and then to the exit of the device. At the end of the flow measurement cycle, the AGZU measuring line is closed and a liquid column remains in the measuring chamber 3, the height of which is determined by the height of the partition 2. The gas entering the device from the AGZU through the pipe 8 blows and releases the drain chamber 4. The pipe 9 is necessary for alignment pressure in the upper part of the measuring tank and the lower part of the drain chamber 4. This tube eliminates the formation of a gas plug in the upper part of the device and, accordingly, the flow of liquid from the measuring th chamber 3 into the drain chamber 4 after stopping the flow of oil-water liquid into the device. Using a pressure sensor 7, for example, a differential pressure gauge "Sapphire DD", the hydrostatic pressure of the liquid column in the measuring chamber 3 is measured.

The automation of the water cut measurement process is directly related to the operation of the gas-filling unit, which opens and closes the line with a turbine meter for volumetric flow of liquid, and also automatically connects the tested wells to the gas-separator separator. After the flow of the next portion of the oil-water liquid through the device, the signal from the pressure sensor 7 enters the controller that controls the operation of the AGZU. The controller converts the pressure into density, and the density into the coefficient of water cut. The result is automatically sent to the database or other storage.

The operation of the inventive device for measuring the water content of oil in wells complete with AGZU, for example, of the type "Sputnik AM-40" in oil fields provides a reliable determination of water and oil in a liquid. The simplicity of the device does not require qualified maintenance personnel, while eliminating the need for liquid sampling with subsequent analysis in a chemical laboratory. Thus, the use of a device for measuring the water content of oil in wells in conjunction with the AGZU, which measures the flow rate of oil producing wells, allows us to automate the process of measuring the water content of oil-water liquids directly in oil fields.

Sources of information

1. Isakovich R.Ya., Popadko V.E. Control and automation of oil and gas production: A textbook for technical schools. -M .: Nedra, 1985.

2. US Patent No. 5394339 A, cl. G 01 N 9/26, publ. 02/28/1995.

3. Isakovich R.Ya., Loginov V.I., Popadko V.E. Automation of production processes in the oil and gas industry. Textbook for high schools. -M .: Nedra, 1983, p. 314-344.

Claims (1)

A device for measuring the water cut of oil in wells, containing a measuring tank, a pressure measuring sensor, characterized in that the measuring tank contains a partition separating it into a measuring and drain chamber, and in the upper part of the measuring tank there is a pipe for blowing the drain chamber with gas, connected by a pipe to bottom of the drain chamber.

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