RU2778221C1 - Installation for determining the saturation temperature of liquid hydrocarbons with paraffin - Google Patents

Abstract

FIELD: measuring technology.

SUBSTANCE: invention relates to an installation for determining the saturation temperature of liquid hydrocarbons with paraffin. The installation for determining the saturation temperature of liquid hydrocarbons with paraffin includes the first, second high-pressure pumps and a device for conducting research. The pumps have a common thermostatic system. The device for conducting research has a two-circuit temperature control system and a housing. The first and second measuring cells are installed in the housing. The first measuring cell is equipped with illumination, an electron microscope and a high-pressure visual chamber. The second measuring cell is equipped with an IR radiation receiver, an IR radiation transmitter and a high-pressure photometric chamber. The entrance of the visual high-pressure chamber is connected to the inner cavity of the first high-pressure pump. The output of the visual high-pressure chamber is connected to the input of the photometric high-pressure chamber. The output of the high-pressure photometric chamber is connected to the inner cavity of the second high-pressure pump.

EFFECT: increase in the reliability and speed of the measurement process, increase in the unambiguity of the interpretation of the measurement results, the possibility of multiple measurements of the saturation temperature of liquid hydrocarbons with solid particles by two duplicate methods: photometric and visual.

6 cl, 1 dwg

Description

The invention relates to equipment for studying the physical properties of liquid hydrocarbons and can be used in stationary and field production laboratories, organizations producing and transporting liquid hydrocarbons, as well as in research laboratories for determining the saturation temperature (beginning of crystallization) of liquid hydrocarbons with solid particles (paraffin and asphalt, resin and paraffin deposits), as well as to determine the saturation pressure of samples with gas at various temperatures.

A known installation for determining the temperature of saturation of oil with paraffin, including a high-pressure chamber, the upper part of which is connected to an illuminator with a set of lenses, and its cavity is connected by one end of a thermocouple, the second end of which is placed in a bottle with liquid nitrogen, devices for inlet and outlet of the sample, a photo sensor and a thermostat with a thermometer, characterized in that it is equipped with a measuring press with a pressure gauge, a measuring valve, a light guide, a switching generator and a recording potentiometer, and a high-pressure chamber, sample injection devices and a measuring valve are placed in a thermostat, while the lower part of the chamber high pressure is connected by means of a light guide to a photo sensor, a measuring press is connected to the body of the lower part of the measuring valve, to which a device for sampling is connected via a pipeline, moreover, the illuminator, photo sensor and thermocouple are connected to a commutator generator, which is connected to a self-writing potentiometer (see . RF patent No. 2153068, IPC E21B 47/06, publ. 20.07.2000).

The disadvantages of the above installation are the limited use (light oils), metrological characteristics that do not meet modern requirements, the imperfection of the temperature control system and the low level of automation.

Known device PTP-1M, including a pressure vessel with an inlet fitting and an outlet valve, equipped with two sight glasses, which are installed in movable screw-in tubes on the same vertical axis. The movable tube allows you to adjust the distance between the sight glasses and thereby change the thickness of the layer of the studied oil from 1 to 5 mm (Experimental methods for the study of paraffinic oils / Edited by K.D. Ashmyan. - M .: OAO VNIINEft, 2004. - 108 With).

The disadvantages of the device described above are: insufficient temperature control accuracy, low level of automation, lack of a mixing system, low measurement accuracy. In the modified version of PTP-2, solutions have been introduced that improve the accuracy of temperature control of the chambers.

A device is known, which is a module for the release of solid hydrocarbons and the release of asphaltenes, included in the device for measuring the thermodynamic properties of reservoir fluids (see RF patent No. 2606256 IPC G01N 11/16, E21B 49/00, publ.

The disadvantage of the modules described above is the low precision of studies, the results of which are used primarily for QC (quality control).

The closest analogue of the claimed is a device for determining the saturation temperature of hydrocarbons with paraffin, including devices for sample input and output, a high-pressure chamber, the internal cavity of which is connected to the working cylinder of the micropress (see RF patent No. 82039 MPK G01N 21/00, publ. 10.04. 2009).

The disadvantages of the described device are: the absence of a fluid mixing system, the lack of visualization of the high pressure chamber and the impossibility of simulating the determination of the saturation temperature of hydrocarbons with paraffin in the stream.

Technical problems in the operation of the devices discussed above are:

- lack of a fluid mixing system, which does not allow for multiple measurements of the same sample;

- lack of means of visualization of the measurement process in the chamber, which does not allow the use of a visual method for determining the saturation temperature in addition to the photometric one, or vice versa;

- the impossibility of simulating the determination of the saturation temperature of hydrocarbons with paraffin in the stream;

- the impossibility of a correct assessment of the quality of the test sample by determining its gas saturation pressure.

The task to be solved by the claimed is to expand the functionality of the installation and improve its metrological characteristics.

The technical result is:

- increasing the reliability and speed of the measurement process by increasing the accuracy of temperature control of high-pressure chambers, as well as improving metrological characteristics and using modern measuring and automation tools;

- increasing the unambiguity of the interpretation of measurement results by determining the saturation temperature of liquid hydrocarbons with solid particles simultaneously by two redundant methods: photometric (in the infrared (IR) range) and visual;

- the possibility of carrying out multiple (repeated) measurements of the saturation temperature of liquid hydrocarbons with solid particles of one sample by two redundant photometric and visual methods by ensuring the phase equilibrium of the sample in preparation for its study and in the process by pumping from one high-pressure pump to another without the use of special mixing devices .

The technical result is achieved due to the fact that the installation for determining the saturation temperature of liquid hydrocarbons with paraffin includes the first and second high-pressure pumps, which have a common thermostatic system, a research device with a double-circuit thermostatic system and a housing in which the first and second measuring cells, the first measuring cell is equipped with illumination, an electron microscope and a visual high-pressure camera, the second measuring cell is equipped with an infrared radiation receiver, an infrared radiation transmitter and a high-pressure photometric chamber, while the inlet of the visual high-pressure chamber is connected to the internal cavity of the first high-pressure pump pressure, and the output - with the input of the photometric high-pressure chamber, the output of which is connected to the internal cavity of the second high-pressure pump.

The general thermostatic system of high pressure pumps can be made in the form of two liquid jackets, each of which covers one of the high pressure pump housings and is connected to a liquid thermostat.

The double-circuit thermostating system of the research device can consist of the first circuit, made in the form of a thermoelectric thermostat, installed in the body of the research device, and the second circuit, made in the form of a thermostating jacket of the said body, communicated with liquid jackets covering the high-pressure pump bodies.

The installation may contain test fluid temperature sensors located in the first and second measuring cells, as well as test fluid temperature sensors located in the internal cavities of the first and second high-pressure pumps and connected to a liquid thermostat.

The installation may include a pressure sensor installed on the pipeline connected to the internal cavity of the first high pressure pump and a pressure sensor installed on the pipeline connected to the internal cavity of the second high pressure pump.

Pressure sensors, a liquid thermostat, a thermoelectric thermostat, an infrared radiation receiver, an electron microscope can be connected to a control unit connected to a personal computer.

The use of a hydraulic system of two high-pressure pumps makes it possible: firstly, to carry out sample mixing and homogenization by pumping it from one pump to another without the use of special mixing devices; secondly, to accurately determine the current volume of the entire system occupied by the fluid; thirdly, to implement the method of isothermal expansion or compression of the system, both in single-channel mode and in the mode of expansion according to the pressure differential (with simultaneous pumping of fluid from one pump to another).

The use of a double-circuit thermostating system of the device for conducting research allows you to set and control the temperature in the visual and photometric high-pressure chambers with high accuracy.

The use of the first and second measuring cells together with two high-pressure pumps makes it possible to carry out multiple measurements of the saturation temperature of liquid hydrocarbons with solid particles simultaneously by photometric and visual methods, as well as to measure the saturation pressure in discrete and continuous modes.

The essence of the claimed installation for determining the saturation temperature of liquid hydrocarbons with paraffin is illustrated in the drawing.

The drawing shows a schematic representation of an installation for determining the saturation temperature of liquid hydrocarbons with paraffin.

In the figure, dotted lines show data lines, thin lines show test fluid lines, and thick lines show thermostatic fluid lines.

In the drawing, the installation elements for determining the saturation temperature of liquid hydrocarbons with paraffin are indicated by the following positions: visual chamber 1 high pressure, photometric chamber 2 high pressure, upper optical tube 3 of the first measuring cell, upper optical tube 4 of the second measuring cell, backlight 5 of the upper optical tube 3 , IR transmitter 6, upper sight glass 7 of visual chamber 1, upper sight glass 8 of photometric chamber 2, liquid temperature control jacket 9, lower optical tube 10 of the first measuring cell, lower optical tube 11 of the second measuring cell, electron microscope 12, IR receiver -radiation 13, lower sight glass 14 of visual chamber 1, lower sight glass 15 of photometric chamber 2, first high pressure pump 16, second high pressure pump 17, liquid thermostat 18, pressure sensor 19 installed on the pipeline connected with the internal cavity of the first pump ca 16, pressure sensor 20 installed on the pipeline connected with the internal cavity of the second pump 17, temperature sensor 21 installed in the first measuring cell, temperature sensor 22 installed in the second measuring cell, temperature sensor 23 installed in the internal cavity of the first pump 16 , temperature sensor 24 installed in the internal cavity of the second pump 17, control unit 25, personal computer 26, vacuum pump 27, thermoelectric thermostat 28, valve 29 installed on the exit line of the test fluid (liquid hydrocarbons) from the high-pressure photometric chamber 2, valve 30 and valve 31 installed on the test fluid supply line to the installation for determining the saturation temperature of liquid hydrocarbons with paraffin, valve 32 installed on the pipeline connecting the internal cavity of the first high pressure pump 16 with the test fluid supply line to the installation for determining the saturation temperature of liquid hydrocarbons. paraffin, valve 33, installed on the pipeline connecting the internal cavity of the second high pressure pump 17 and the line for the removal of the test fluid from the research device.

The installation for determining the saturation temperature of liquid hydrocarbons with paraffin includes a research device having a housing in which the first measuring cell, the second measuring cell and a thermoelectric thermostat 28 are installed. between the first and second measuring cells.

The first measuring cell consists of an upper optical tube 3 and a lower optical tube 10, between which there is a visual high-pressure chamber 1, equipped with an upper viewing glass 7 and a lower viewing glass 14. In the upper end part of the upper optical tube 3 there is a backlight made in the form of a lamp backlight 5, and an electron microscope 12 is installed in the lower end part of the lower optical tube 10. The first measuring cell is equipped with a temperature sensor 21.

The second measuring cell consists of an upper optical tube 4 and a lower optical tube 11, between which there is a high-pressure photometric chamber 2, equipped with a viewing glass 8 and a viewing glass 15. An infrared radiation transmitter 6 is located in the upper end part of the lower optical tube 11. In the lower end part of the lower optical tube 11 is equipped with an infrared radiation receiver 13. The second measuring cell is equipped with a temperature sensor 22.

The first high pressure pump 16 and the second high pressure pump 17 are servo driven automatic plunger pumps controlled by a control unit.

The test fluid supply line to the installation for determining the saturation temperature of liquid hydrocarbons with paraffin is connected to the PVT cell, in which the fluid is in a single-phase state, or to the sampling equipment containing the fluid sample, which is in a single-phase state (not shown in the drawing).

The internal cavity of the first high pressure pump 16 is connected to the test fluid supply line to the installation through a pipeline for the test fluid, on which a pressure sensor 19 and a valve 32 are installed in series. The internal cavity of the first high pressure pump 16 is equipped with a temperature sensor 23.

The line for supplying the test fluid to the installation for determining the saturation temperature of liquid hydrocarbons with paraffin is equipped with valve 30 and valve 31. Valve 30 is located on the line for supplying the test fluid to the installation up to the junction with it of the pipeline for the test fluid connected to the pump 16. Valve 31 is located on the line test fluid supply after the junction with it of the pipeline for the test fluid connected to the pump 16.

The internal cavity of the second high pressure pump 17 is connected to the photometric chamber 2 through a pipeline on which a pressure sensor 20 and a valve 33 are installed. The internal cavity of the second high pressure pump 17 is equipped with a temperature sensor 24.

High pressure pumps 16 and 17, driven by servo drives, allow for controlled mixing of the sample and set various measurement modes.

The test fluid withdrawal line from the research device is equipped with a valve 29, equipped with a vacuum pump 27, used as a drain when the unit is purged and connected to a pipeline connected to the internal cavity of the pump 17.

The first high-pressure pump 16 is provided with a thermostatic liquid jacket that surrounds its body and communicates with the liquid thermostat 18 through a pipeline with a shut-off valve. In order to ensure continuous circulation of the thermostating liquid, said thermostatic liquid jacket is connected to the thermostatic liquid jacket 9 of the research device through a pipeline.

The second high-pressure pump 17 is also provided with a thermostatic liquid jacket, which surrounds its body and communicates with the liquid thermostat 18 through a pipeline with a shut-off valve. Also, said thermostatic liquid jacket is connected to the thermostatic liquid jacket 9 of the research device through a pipeline. Temperature sensors 23 and 24 are connected to the liquid thermostat 18.

The installation for determining the saturation temperature of liquid hydrocarbons with paraffin contains a control unit 25 based on software and logistics controllers, which is connected to a personal computer 26 with a software interface.

A pressure sensor 19, a pressure sensor 20, a thermoelectric thermostat 28, an electron microscope 12, an IR receiver 13, a liquid thermostat 18, and high-pressure pump servomotors are connected to the control unit 25. Automation and control of the installation, processing of the results of the experiment was achieved through the use of modern technical means based on program and logistics controllers, a personal computer and specialized software.

Installation for determining the saturation temperature of liquid hydrocarbons with paraffin operates as follows.

Turn on the control unit. The pistons of the first 16 and second 17 high-pressure pumps are brought to the extreme position corresponding to the minimum volume of liquid in the internal cavity of the high-pressure pumps (dead volume, which is measured previously). The installation is evacuated. Next, the visual 1 and photometric 2 chambers, the internal cavities of the high-pressure pumps 16, 17, as well as the supply lines and fittings are thermostated. Temperature control is carried out using a liquid thermostat 18 and a thermoelectric thermostat 28 to the sample temperature required by the conditions of the studies and experiments.

The interior of the first high pressure pump 16 is connected to a PVT cell or sampling equipment (not shown) in which the fluid is in a single phase state.

The test fluid sample is loaded into the internal cavity of the first pump 16 through open valves 30, 32 (with valve 31 closed) while maintaining a pressure corresponding to the pressure in the test fluid supply line to the installation.

Carry out temperature control of the first 16 and second 17 pumps to the temperature required by the conditions of the experiment. Temperature control is carried out by means of a thermostating system common to both pumps, which is made in the form of two liquid jackets, each of which covers one of the high-pressure pump housings and is connected to a liquid thermostat 18.

The temperature is set and controlled in the visual 1 and photometric 2 high-pressure chambers by means of a double-circuit temperature control system. The first circuit of the thermostating system is implemented by a thermoelectric thermostat 28, and the second thermostatic circuit is made in the form of a thermostating jacket of the mentioned housing, communicated with liquid jackets covering the housings of the first 16 and second 17 high pressure pumps.

After loading the sample, valve 30 is closed and valve 31 and valve 33 are smoothly opened, filling the visual chamber 1 and photometric chamber 2 with the sample, as well as the cavity of the second pump 17 while maintaining a constant pressure. At least two sample pumping cycles are performed, during which the sample is pumped back from the internal cavity of the second pump 17 to the internal cavity of the first pump 16, which ensures sample mixing.

The saturation temperature of liquid hydrocarbons with solid particles is measured in accordance with the current regulatory documentation (OST 39.034-76 "Oil. Method for determining the saturation temperature of oil with paraffin. Photometric method"). Temperature measurements are carried out by means of temperature sensors 21, 22.

The change in pressure and temperature during research is carried out stepwise or continuously.

As a rule, measurements are carried out in the mode of isobaric cooling of the system on several isobars by the photometric and visual methods. To do this, set the operating mode of the pumps (static or dynamic) and perform a gradual (with a certain specified cooling rate °C/min) cooling of the cell to the saturation temperature of the test sample with paraffin in the isobaric mode.

Cooling is performed by changing the temperature in a liquid thermostat 18 and a thermoelectric thermostat 28. The photometric method consists in the fact that the waves from the IR transmitter 6 pass through the fluid layer located in the photometric chamber 2, are received by the IR radiation receiver 13 and using the block control 25, the converted signal with the measured value of the photocurrent intensity is transmitted to a personal computer 26. From pressure sensors 19, 20 and temperature 21, 22, the signals are transmitted similarly to a personal computer 26. Data processing and graphical representation is carried out in a personal computer according to the dependence of the photocurrent intensity on temperature .

The temperature at which solid paraffin particles appear in the test sample (determined by interpreting the characteristic abrupt decrease in photocurrent intensity) is taken as the saturation temperature of liquid hydrocarbons with paraffin.

Measurement by the visual method involves discrete photography of the lower viewing glass 14 of the visual camera 1 by an electron microscope 12, followed by software processing of the obtained images. The saturation temperature of liquid hydrocarbons with solid particles is determined by the time of the beginning of the formation of paraffin crystals.

Determination of the saturation pressure of the sample is carried out by volumetric and visual methods in the mode of isothermal expansion (or compression) of the system. By determining the saturation pressure of deep and separator samples of liquid hydrocarbons by two methods, it is possible to assess the quality of samples before and immediately after research.

Saturation pressure measurement can be carried out in two ways: in discrete mode and continuous scanning. Both methods are automatic.

The difference between the modes is that in the discrete mode, cyclically sequential procedures are carried out: sample recovery, expansion of the system, increase in volume), mixing, measurement of parameters and then repeated, and in the continuous mode, measurements are carried out continuously, the expansion of the system is also performed continuously at low speed. To determine the saturation pressure of liquid hydrocarbons with gas by the volumetric method, the dependences "pressure-volume" or "pressure-volume increment" are processed. Saturation pressure corresponds to the point of sharp change in the rate of change of pressure.

To determine the saturation pressure by a visual method, the video image from the microscope 12 is analyzed and the formation of the first bubble of the gas phase is visually observed, the pressure at which this happened is taken as the saturation pressure.

An installation for determining the saturation temperature of liquid hydrocarbons with paraffin can find practical application in the oil and gas industry, since a prototype containing a combination of the above features has been manufactured and successfully passed laboratory tests in determining the temperature of the onset of crystallization of paraffin or asphalt-resin-paraffin deposits in oil, gas condensate and liquid mixtures. hydrocarbons.

A distinctive feature of the installation is the ability to carry out measurements in a dynamic mode, simulating the process of sedimentation of solid particles in a pipeline, which is an urgent task for transporting liquid hydrocarbons through main pipelines. The measurements performed showed high reproducibility of the saturation pressure measurement results not only for oils and gas condensates, but also for deep water samples. The practical significance of the installation is related to its reliability, ease of maintenance and operation, and versatility, which can be useful when using field laboratories directly at the field.

Claims (6)

1. The installation for determining the saturation temperature of liquid hydrocarbons with paraffin includes the first and second high-pressure pumps, which have a common thermostatic system, a research device with a double-circuit thermostatic system and a housing in which the first and second measuring cells are installed, the internal cavity of the first high-pressure pump is connected to the test fluid supply line, the first measuring cell consists of an upper optical tube and a lower optical tube, between which a high-pressure visual camera is located, the upper optical tube of the first measuring cell is equipped with illumination, and the lower optical tube of the first measuring cell is equipped with an electron microscope , the second measuring cell consists of an upper optical tube and a lower optical tube, between which there is a high-pressure photometric chamber and is equipped with an IR radiation receiver and an IR radiation transmitter, o m of which pass through the fluid layer located in the photometric chamber and are received by the IR radiation receiver, while the inlet of the visual high pressure chamber is connected via a pipeline to the inner surface of the first high pressure pump, and the outlet is connected to the inlet of the photometric high pressure chamber, the outlet of which is connected with the internal cavity of the second high-pressure pump, which is connected to the test fluid outlet line from the research device, while the outlet line is equipped with a vacuum pump, and the high-pressure pumps are driven by servo drives with the possibility of controlled mixing of the sample and setting the measurement modes. 2. Installation according to claim 1, characterized in that the common thermostatic system of high-pressure pumps is made in the form of two liquid jackets, each of which covers one of the high-pressure pump housings and is connected to a liquid thermostat. 3. Installation according to claim. 2, characterized in that the two-circuit thermostating system of the research device consists of the first circuit, made in the form of a thermoelectric thermostat, installed in the housing of the research device, and the second circuit, made in the form of a thermostating jacket of the mentioned housing, communicated with liquid jackets covering high-pressure pump casings. 4. Installation according to claim 2, characterized in that it contains temperature sensors of the test fluid located in the first and second measuring cells, as well as temperature sensors of the test fluid located in the internal cavities of the first and second high pressure pumps and connected to a liquid thermostat. 5. Installation according to claim 3, characterized in that it contains a pressure sensor installed on the pipeline connected to the internal cavity of the first high pressure pump and a pressure sensor installed on the pipeline connected to the internal cavity of the second high pressure pump. 6. Installation according to claim 5, characterized in that pressure sensors, a liquid thermostat, a thermoelectric thermostat, an infrared radiation receiver, an electron microscope are connected to a control unit connected to a personal computer.

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