RU108105U1 - DEVICE FOR DETERMINING PHASE PERMEABILITY - Google Patents

Abstract

 A device for determining phase permeability, 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 liquid level at the outlet of core holder, pressure sensors, differential pressure gauge for measuring the differential pressure on the test sample, characterized in that, in order to reduce the time to determine the phase permeability, the pipeline (s) for supplying working fluid to the input of the core holder is connected (connected) to the pipeline at the outlet of the core holder a channel with a valve.

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.

Known devices (1-3), allowing to determine the phase permeability of oil and gas reservoirs.

The disadvantage of the described devices is the significant duration of the research process.

It is also known a device (adopted as a prototype) for determining phase permeabilities in reservoir conditions (4), 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 fluids, 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 A potential pressure gauge for measuring the pressure drop across the test sample.

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

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.

Test conditions should ensure the preservation or reproduction of the natural physicochemical characteristics of the rock system — formation fluids, and the maintenance of temperature and pressure values corresponding to the formation during the experiment. The velocity of the joint fluid flow during the test should be selected based on the values of the field velocities of displacement of the displacement front. When conducting tests, it is necessary to use reservoir oil and water, or their models (1).

When supplying liquids to the sample, it is necessary to fulfill a number of conditions, in particular: the pressure drop inside the core sample should not exceed 10 atm. and rock pressure should always exceed the vapor pressure in the sample by at least 30 atm. (3). OST 39-235-89 recommends an experiment to determine phase permeabilities at a working pressure as close as possible to the reservoir pressure, while the working pressure should not be less than 10 times the pressure drop across the entire sample so as not to take into account the change in gas volume during flow through sample (1).

The need to comply with these conditions leads to significant complexity associated with the long duration of the process of filtering oil and water through the sample.

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 the operating speed and continue pumping fluids until steady steady state filtration is achieved (1, 4).

As the experiments showed, the saturation in each filtration mode is established after pumping a certain volume of the mixture, regardless of whether it was initially pumped at high speed or if filtration was carried out only at operating speed.

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 to a given value of the working pressure, it is necessary to reduce the pumping speed.

The technical result of the proposed utility model is to reduce the time for determining phase permeabilities by supplying a portion of the pumped liquid to the core holder outlet.

This is achieved by the fact that in the known device containing plunger pumps providing oil and water at a reservoir pressure into the sample, a pump for creating rock pressure, a core holder with a test sample installed in it in a rubber cuff, containers with working fluids, back pressure regulator, measured a flask for measuring the liquid level at the outlet of the core holder, a thermostat that maintains a constant temperature in the test sample, a differential pressure gauge for measuring the differential pressure on the test sample, a part of the working fluid is supplied to the output core holder, which inlet line (input lines) is coupled (joined) to the outlet conduit passageway with a valve. In this case, the core is in conditions close to the conditions of the rock. Immediately after establishing the outlet pressure equal to the inlet pressure, the valve at 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.

Since the claimed combination of features exhibits a new property (allows to reduce the time of research) and this new property is the result of introducing into the claimed combination of new distinctive features (using a bypass connecting the input pipelines to the output), this allows us to state that there are significant differences. The lack of descriptions of such devices in general technical and patent sources of information allows us to confirm the presence of novelty in the created technical solution.

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 valve 9, containers with working fluids 10, a back pressure regulator 11, a volumetric flask for measuring the liquid level at the outlet of rnoderzhatelya 12, pressure sensors 13, the differential pressure gauge 14 for measuring the differential pressure on the sample.

The device operates as follows.

The working fluid (water, oil or their mixtures in different ratios) is supplied to the core holder 1 by means of high pressure plunger pumps 3 and 4. At the beginning of the experiment, bypass channel 8, part of the working fluid is transferred from the core holder to the outlet, which ensures an almost instantaneous increase in working pressure fluid outlet. After that, the valve 9 on the bypass channel is closed, 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 can be increased at an increased speed, which will ultimately reduce the time of the experiment (research).

Each pumping mode continues until steady stationary filtration sets in, which is recorded according to the differential pressure gauge 14 and electrical resistance measurements on the test sample / 4 /, 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 5/1, 4 /.

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;

ΔР - pressure difference on 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 of experiments on filtering the working fluid through the core sample.

Thus, the claimed technical solution provides a positive economic effect when used, meets the criteria of a utility model.

Information sources:

1. OST 39-235-89. Oil. A method for determining phase permeabilities in laboratory conditions with joint stationary filtration.

2. Ivanov M.K., Kalmykov G.A., Belokhin B.C. and other Petrophysical methods for the study of core material. Textbook in 2 books. Prince 2: Laboratory methods for petrophysical studies of core material. - M.: Publishing House Mosk. University, 2008 .-- 113 p.

3. Instruction manual for an automated software-measuring complex for petrophysical core research PIK-OFP / EP-3. - Novosibirsk: ZAO Geologika, 2008. - 33 p.

4. Dobrynin V.M., Kovalev A.G., Kuznetsov A.M. et al. Phase permeabilities of oil and gas reservoirs. - M.: VNIIOENG, 1982. - (Review inf. Ser. "Geology, geophysics and development of oil fields"). - 56 p.

Claims (1)

A device for determining phase permeability, 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 liquid level at the outlet of core holder, pressure sensors, differential pressure gauge for measuring the differential pressure on the test sample, characterized in that, in order to reduce the time to determine the phase permeability, the pipeline (s) for supplying working fluid to the input of the core holder is connected (connected) to the pipeline at the outlet of the core holder a channel with a valve.