RU2775462C1 - Device for the study of porous rock samples - Google Patents

Abstract

FIELD: measuring technology.

SUBSTANCE: invention relates to a laboratory installation for studying the properties of porous rocks and can be used to determine the permeability of rock samples under conditions simulating formation. The device contains a core holder housing, a rubber gasket, plungers for preloaded core with a channel for supplying and removing the working agent and sealing flanges, into which the upper and lower support flanges, split rings and fixing flanges, a jack with a housing for attachment to the lower support flange are additionally inserted, and the fastening of the core holder housing with support flanges is carried out using split half-rings, which are fixed by flanges, a waveguide is installed on the upper end of the upper plunger, connected to it by means of a stud, and an acoustic radiator is fixed to the upper end of the waveguide by soldering, a support flange is located in the middle part of the waveguide.

EFFECT: increased reliability, simplified design and increased functionality of the device for core research.

1 cl, 5 dwg

Description

The invention relates to the study of the properties of porous rocks and can be used to determine the permeability of rock samples under conditions simulating reservoir. The study of permeability on cores taken from reservoir layers in laboratory conditions is based on an assessment of the change in permeability when they are physically affected by the field of elastic vibrations in the process of filtering the working agent. Research on the device contributes to obtaining information about the filtration properties of rock samples in reservoir conditions, as well as the influence on them of the stimulating factor of increasing fluid permeability in the field of elastic vibrations.

A device is known: "Core holder" (patent RU No. 2685466 G01N 15/08 dated May 25, 2018), containing a vertically installed pipe with a core sample placed in it, upper and lower plungers with mechanisms for sealing and preloading the core. The plungers have through axial channels for supply and discharge of the working agent, gas or liquid. The disadvantage of the device is the inability to provide radial compression of the core and connect the source of elastic vibrations to the ends of the core.

Known "Device for determining the porosity and permeability of rock samples" (patent RU No. 2342646 G01N 3/00, G01N 15/08 dated February 21, 2007), containing a core holder containing a hollow body, an upper and lower punch with axial channels and a sleeve made of elastic material with a cylindrical rock sample placed inside it with flat parallel ends. The disadvantage of the device is the complexity of the design, which requires a large amount of work on the installation and dismantling of the frame structure for installing and extracting a rock sample, as well as the inability to connect a source of elastic vibrations to the ends of the rock sample and install vibration sensors to the punches.

Known "Device for determining the characteristics of rock samples" (patent RU No. 2284413 E21S 39/00 dated 10/31/2005), containing a chamber with a core holder, fittings with tubes for supplying and removing fluid, a fitting with a tube for supplying liquid to create a compressing pressure, two liners installed along the ends of the core and piezoceramic plates mounted on them - on one side of the core is a vibration emitter, on the other side of the core is a vibration receiver. The disadvantage of the device is the inability to create an axial (rock) pressure on the core, as well as the possibility of supplying elastic vibrations of high intensity at a low frequency, compared with the frequency at which measurements of the propagation velocity of longitudinal and transverse sound velocities in the core are made.

The closest in technical essence is the description of the utility model to the patent "Core holder" (utility model to patent RU No. 111664, G01N 15/08 dated 07.07.2211), containing a core holder, a rubber cuff, plungers for preloaded core in the axial direction, a fitting in the chamber hydrocompression, sealing sleeves and mechanisms for preloading the rubber cuff, as well as the main and auxiliary channels in the plungers for supplying and discharging the working agent. The disadvantage of the model is the complexity of the installation of the structure, which requires a complete disassembly of the design of the compression mechanisms when changing the core and the inability to adjust the axial compression in the process of core research, and also in the design of the plungers there is no possibility of connecting vibration sensors and connecting a source of elastic vibrations.

The objective of the invention is to increase the reliability, simplify the design and improve the functionality of the device for examining the core.

The task is achieved by the fact that in the device for examining the core, containing the body of the core holder, rubber cuff, plungers for preloading the core with a channel for supplying and discharging the working agent and sealing flanges, additionally introduced upper and lower support flanges, split rings and fixing flanges, a jack with a fastening body to the lower support flange, and the core holder body with the support flanges is fastened using split half-rings, which are fixed by flanges, a waveguide is installed on the upper end of the upper plunger, connected to it with a pin, and an acoustic emitter, in the middle part of the waveguide there is a support flange with a diameter greater than the diameter of the plunger, a welded structure is attached to the lower support flange using a threaded connection, consisting of three parts: a connecting flange, a casing pipe with a cutout and a connecting flange for connection with hydraulic jack.

On FIG. 1 shows the assembly of the device. Assembly of the device begins with the lower support flange 8, on which the body of the core holder 6 is installed from above, and the connecting flange 26 is connected along the thread with the body pipe 24 and the connecting flange 27 and the hydraulic jack installed in it. The body pipe 24 has a welded connection with flanges 26 and 27 and forms a single assembly of the structure, in which there is a through cutout for draining the tube with a fitting 21 for supplying liquid to the core holder chamber for radial compression of the core through a rubber cuff, as well as a fitting 23 for draining the working agent from the lower plunger 4. A sealing flange 12 is installed on the support flange 8, in which there is a groove along the outer diameter for installing a sealing rubber ring 29, Fig. 3. In the upper part of the sealing flange there is a conical surface on which a rubber cuff 28 is put on. In the sealing flange 12 there is a hole into which a tube 25 is inserted to supply fluid to the core holder chamber, while the tube is welded at the end 30 to the sealing flange 12, as on the other hand, it has a fitting 21. The body of the chamber of the core holder 6 is installed on the lower support flange 8 and is put on the sealing ring 29 on the flange 8. fourteen.

In the upper part of the device, the assembly takes place similarly by installing the sealing flange 11 in the body of the core holder chamber and in the rubber cuff 28. The upper support flange 7 with the upper plunger 3 pre-installed in it is installed on the core holder chamber and the upper sealing flange 11 and is fixed with a split ring 9 and a fixing flange 13.

A waveguide 2 is installed on the upper plunger 3 by means of a connecting pin 17, on the upper end of which a magnetostrictive electroacoustic transducer 1 is fixed by soldering.

The upper plunger has a central hole 18 (Fig. 2), which in the lower part adjoins the core, and in the upper part ends with a fitting 19 for connection to the hydraulic system. The central hole in the lower plunger 4 is similarly arranged, to which the fitting 23 is connected.

The sealing of the sealing flange 11 and 12 is carried out using a rubber ring 29 (Fig. 3), which is located in the annular groove along its outer diameter.

The device works as follows.

The initial state of the device begins with the installation of the base 8 in the hole on any work surface. From below, the welded structure is screwed onto the plunger using connection 26. The lower plunger 4 is installed in the connecting unit with the jack 15. The sealing flange 12 and the rubber cuff 28 are put on the plunger 4, the body of the core holder 6 is installed and fixed with the help of half rings 10 and fixed by the flange 14. Installed sealing flange 11 in connection with the rubber cuff 28 and body 6 using rubber rings 29 as well as for the lower sealing flange.

This completes the preparatory part of the assembly of the device and remains in this unchanged state for the entire operation of the installation.

The work on the study of the core begins with the installation of the core sample 5 in the rubber cuff through the hole in the flange 11. The assembly, consisting of the upper plunger 3, the upper support flange 7 previously put on it and the waveguide 2 fixed on the plunger, is inserted into the rubber cuff 28 and fixed split semi-rings 9 and is fixed by flanges 13. This completes the assembly of the device, after which working agents are fed into the core through fittings 19 and 23, as well as into the cavity of the core holder body 6 and rubber cuff 28. With the help of a jack 15, the core is compressed in the axial direction and the necessary rock pressure is provided during the operation of the device by supplying the working fluid to the hydraulic cylinder of the jack through the fitting 22 (Fig. 1).

The core study process consists of two main parts:

1) study of natural permeability in reservoir conditions,

2) study of permeability depending on the acoustic impact applied from the magnetostrictive electroacoustic transducer.

The study of permeability is carried out according to the standard method for studying the core, previously placed in conditions close to reservoir conditions, by creating axial compression and compression using a jack 15 and supplying fluid under pressure to the cavity between the core holder body and the rubber cuff 28 through the fitting 21. The permeability is assessed according to Darcy's law by measuring the flow rate of the working agent flowing through the core and the pressure drop at the inlet and outlet using fittings 19 and 23. These measurements are needed as initial data for comparison with the results of measurements of the permeability of the core exposed to acoustic impact in the second part of the study.

In the second part of the research, a magnetostrictive emitter is put into operation, as a result of which an acoustic field of elastic vibrations is applied to the core, which helps to increase its permeability. Permeability studies are performed similarly to the first part, after which a comparison and evaluation of the measurement results is made.

In FIG. 4 and FIG. Figure 5 shows graphs of changes in core permeability during filtering of the working agent and acoustic impact. Since the initial parameters of the filtration properties of the cores are significantly different, for the first core in Fig. 4, the permeability coefficient is Kpr=8.02 mD, and for the second core in Fig. 5, Kpr=89.31 mD, the influence of the acoustic field is also different. The maximum increase in permeability for the first core was 60%, and for the second - 150% relative to the initial one. Thus, the device allows you to study the effect of an acoustic field on the permeability of porous rock samples under conditions close to reservoir conditions, determine the parameters of the impact and evaluate its effectiveness to increase the productivity of a productive formation saturated with oil or water.

Thus, the set of essential features of the device, according to the invention, provides for the study of porous rock samples in conditions close to reservoir, the device is simple, reliable and provides extended functionality for studying the permeability of cores under the influence of external acoustic influence of a working agent stimulating filtration (water, kerosene). , oil), which serves as a petrophysical rationale for enhanced oil recovery.

Sources:

1. RF patent No. 2685466 G01N 15/08 dated 05/25/1018.

2. RF patent No. 2342646 G01N 15/08 dated February 21, 2007.

3. RF patent No. 2284413 Е21С 39/00 dated 10/31/2005.

4. Patent of the Russian Federation No. 2343281 E21C 39/00 dated May 21, 2007.

5. RF patent No. 2680843 G01N 33/24, C01N 15/08, E21B 49/00 dated 03/15/2018.

6. RF patent No. 2394988 Е21В 49/00, Е21С 30/00, G01N 15/08 dated 12/31/2008.

Claims (1)

A device for studying rock samples, containing a core holder body, a rubber cuff, plungers for core compression with a channel for supplying and discharging a working agent, and sealing flanges, characterized in that, in order to increase reliability and expand functionality, an upper and lower support are additionally introduced into it. flanges, split rings and fixing flanges; an acoustic emitter is fixed to the upper end of the waveguide by soldering, in the middle part of the waveguide there is a support flange with a diameter larger than the plunger diameter, a welded structure consisting of three parts is attached to the lower support flange by means of a threaded connection: a connecting flange, a cut-out pipe and connecting flange for connection to a hydraulic jack.

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