RU155978U1 - DEVICE FOR DETERMINING PHASE PERMEABILITY - Google Patents

Abstract

A device for determining phase permeabilities, containing a core holder with a test sample installed in it in a rubber cuff, a thermostat that maintains a constant temperature in the test sample, plunger pumps for supplying working fluids (oil and water) to the test sample at reservoir pressure, a pump for creating a mining pressure, pipelines for supplying and discharging working fluids, back pressure regulator, containers with working fluids, volumetric flask for measuring the level of liquid at the outlet of a core holder, pressure sensors, a differential pressure gauge for measuring the pressure drop across the test sample, a bypass channel connecting the input pipe to the output pipe, characterized in that it further comprises an electromagnetic valve installed in the bypass channel, and a control unit connected to the electromagnetic valve and differential pressure gauge.

Description

The utility model relates to the field of studying the phase permeability of oil and gas reservoirs and can be used to solve a large number of geo-field problems.

A device is known for determining phase permeabilities in reservoir conditions (RU 108105, 09/10/2011), which contains plunger pumps that supply oil and water to the sample at reservoir pressure, a core holder designed to be installed in the rubber cuff of the test sample, containers with working liquids, backpressure regulator, volumetric flask for measuring the liquid level at the outlet of the core holder, thermostat to maintain a constant temperature in the test sample, differential pressure gauge to measure the pressure drop across the test sample, a bypass channel with a valve connecting the inlet to the outlet.

The disadvantage of the described device is the significant duration of the process of determining phase permeabilities.

The objective of the proposed technical solution is to reduce the time and complexity in determining phase permeability by automating the processes of opening and closing the bypass channel connecting the input pipe to the output pipe.

The solution to this problem is achieved by the fact that, according to the known device, including plunger pumps, which supply oil and water to the sample at reservoir pressure, a pump for creating rock pressure, a core holder with a test sample installed in it in a rubber cuff, containers with working fluids, a regulator back pressure, volumetric flask for measuring the liquid level at the outlet of the core holder, a thermostat to maintain a constant temperature in the test sample, differential pressure gauge for measuring the pressure drop across the test sample, the bypass channel connecting the inlet to the outlet, the proposed device contains an electromagnetic valve installed in the bypass channel, and a control unit connected to the electromagnetic valve and differential pressure gauge.

The direct experiment to determine the phase permeability includes a number of modes (experiments), during which oil and water are supplied to the sample in a certain ratio, which varies from experiment to experiment, while the total flow rate of both phases remains constant.

To reduce the time of the experiment, it is allowed at each mode to begin filtering at a speed of 5-10 times higher than the working one to more quickly establish the saturation corresponding to a given ratio of oil to water in the stream. After pumping oil and water at a given ratio in the amount of 2-3 pores of the sample at an increased speed, it is necessary to switch to operating speed and continue pumping fluids until steady steady-state filtration is achieved.

When pumping liquid through the sample at an increased speed due to the low permeability of the sample, the pressure at the inlet to the core holder rapidly increases to the maximum permissible values. To reduce the fluid pressure at the inlet to a predetermined value of the working pressure while maintaining an increased pumping speed, part of the working fluid is fed to the core holder outlet, which opens the solenoid valve installed in the bypass channel connecting the input pipe to the output pipe. In this case, the core is in conditions close to the conditions of the rock. After establishing the outlet pressure equal to the inlet pressure, the solenoid valve on the bypass channel closes, and the filtering process is carried out in the usual manner. Setting the pressure of the working fluid at the outlet of the core holder will allow filtering at an increased speed for a longer time.

This device is especially relevant for low permeability core samples.

The drawing shows a hydraulic diagram of the proposed device.

The device includes a core holder 1 with a test sample installed in it in a rubber cuff, a thermostat 2, which ensures constant temperature in the test sample, plunger pumps 3 and 4, which supply oil and water, respectively, at reservoir pressure, a pump for creating rock pressure 5, pipelines for supplying 6 and discharging 7 working fluids, a bypass channel 8 with a solenoid valve 9, containers with working fluids 10, back pressure regulator 11, volumetric flask for measuring liquid level at the outlet of the core holder 12, pressure sensors 13, a differential pressure gauge 14 for measuring the pressure drop across the test sample, a control unit 15 connected to an electromagnetic valve 9 and a differential pressure gauge 14.

The device operates as follows.

The working fluid (water, oil or their mixtures in different ratios) is supplied with the high pressure plunger pumps 3 and 4 to the input of the core holder 1. Upon reaching the maximum permissible differential pressure, the control unit 15 sends a signal to open the electromagnetic valve 9. In this case, part of the working fluid the bypass channel 8 comes from the input of the core holder to the output, thereby ensuring a rise in the pressure of the working fluid at the output. When the inlet and outlet pressures are equalized (differential pressure becomes zero), the control unit 15 sends a signal to close the solenoid valve 9 and the filtering process continues in the usual manner. Due to the rapid increase in pressure at the outlet of the core holder, the pumping time of the working fluid with increased speed can be increased. Due to the automation of the process of bypassing the working fluid from the input to the output, carried out using the electromagnetic valve 9 and the control unit 15, the time and laboriousness of the experiment (research) is reduced.

Each pumping mode continues until steady steady-state filtration sets in, which is recorded according to the differential pressure gauge 14 and electrical resistance measurements on the test sample, after which a new experiment begins with a different ratio of oil to water in the stream. The number of modes must be at least five.

Based on the measured pressure differential ratios for fixed ratios of oil and water, the phase permeabilities are calculated using the Darcy equation:

,

,

where i is the mode (oil and water consumption);

j is the phase (water, oil);

Q - fluid flow rate, ml / s;

µ — fluid viscosity, MPa · s;

L is the length of the sample, m;

ΔP is the pressure difference across the sample (differential pressure), kPa;

F is the cross-sectional area of the sample, m ² .

Using the proposed device will increase the performance of the study of phase permeability by reducing the time and complexity of experiments on filtering the working fluid through the core sample.

Claims (1)

A device for determining phase permeabilities, containing a core holder with a test sample installed in it in a rubber cuff, a thermostat that maintains a constant temperature in the test sample, plunger pumps for supplying working fluids (oil and water) to the test sample at reservoir pressure, a pump for creating a mining pressure, pipelines for supplying and discharging working fluids, back pressure regulator, containers with working fluids, volumetric flask for measuring the level of liquid at the outlet of a core holder, pressure sensors, a differential pressure gauge for measuring the pressure drop across the test sample, a bypass channel connecting the input pipe to the output pipe, characterized in that it further comprises an electromagnetic valve installed in the bypass channel, and a control unit connected to the electromagnetic valve and differential pressure gauge.

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