CN115032192A - Real core microcosmic visual displacement system under high-temperature and high-pressure conditions and use method - Google Patents

Real core microcosmic visual displacement system under high-temperature and high-pressure conditions and use method Download PDF

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Publication number
CN115032192A
CN115032192A CN202210446144.4A CN202210446144A CN115032192A CN 115032192 A CN115032192 A CN 115032192A CN 202210446144 A CN202210446144 A CN 202210446144A CN 115032192 A CN115032192 A CN 115032192A
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core
pressure
real
displacement
holder
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高辉
薛俊杰
王琛
李腾
程志林
张喆
罗开庆
曹江锋
李宁
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Xian Shiyou University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G01N15/0806—Details, e.g. sample holders, mounting samples for testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G01N15/082—Investigating permeability by forcing a fluid through a sample
    • G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Abstract

The system comprises a displacement system, a temperature control and regulation system, a real core clamping system, a pressure regulation system, a high-definition video digital processing system and an auxiliary system; the method adopts a visual real core model, observes the migration rule and occurrence state of the fluid in the real core porous medium under the conditions of high temperature and high pressure from a microscopic angle by combining a temperature control system, a displacement system and a real core clamping system and a high-definition video digital image processing system, and provides support for the understanding of deepening mechanism in the development process of an oil-gas reservoir.

Description

Real core microscopic visual displacement system under high-temperature and high-pressure conditions and use method
Technical Field
The invention relates to the technical field of oil and gas development, in particular to a real core microscopic visual displacement system under a high-temperature and high-pressure condition and a using method thereof.
Background
In the process of developing an oil and gas reservoir, a conventional cylindrical natural core is mainly used in the current real core indoor physical experiment, the displacement effect simulated by the physical model cannot be visualized, and the flowing rule of fluid in the real core cannot be researched. At present, a commonly used visual rock core displacement experiment mainly uses an etching model and a real sandstone model, wherein the etching model mainly selects a special glass material, refers to a digital image processing result of a natural rock core slice, and adopts a laser etching technology to manufacture a special glass material microscopic visual model close to the pore throat characteristic of the natural rock core, and the model is difficult to simulate the heterogeneity of clay minerals and a pore structure of the real rock core and has a large difference with the pore throat gap characteristic of the actual real rock core. The actual sandstone model is that the actual sandstone is polished and then placed into the matched groove, the periphery of the actual sandstone is bonded by resin glue, the bonded upper pipeline is used as an inlet and an outlet, the bonded position is easy to damage, so that a displacement medium is leaked, and the experiment cannot be performed under the high-temperature and high-pressure condition. Therefore, the development of the real core microscopic visual displacement system capable of simulating the real conditions of the oil-gas reservoir and realizing the high-temperature and high-pressure conditions has important significance for the evaluation of fluid flowing and occurrence states in the development process of the oil-gas field, the guidance of the design of a development mode and the selection of a recovery ratio improving method.
In the existing research, CN201310080236.6 discloses a two-dimensional microscopic visual simulation experiment device and a use method thereof, wherein the device uses a simulated transparent pore model to realize a fluid vertical seepage and any dip plane seepage simulation experiment; CN201610741961.7 discloses a microscopic experimental model of a visual core holder, which solves the problem that fluid or gas can not pass through a core to accurately act on the core due to insufficient sealing property and pressing force of the visual core holder; CN202011013509.1 discloses a microscopic visual holder under high-temperature and high-pressure conditions and a use method thereof, wherein the device uses a glass laser etching model to represent the distribution state of an injected medium; CN202110032226.1 discloses a microscopic visual experimental device for simulating fluid displacement under high-temperature and high-pressure conditions, wherein a glass etching model is adopted to simulate the structural characteristics of the pore throat in an actual rock; CN202110022199.8 discloses a microscopic visualization experimental method for deep reservoir high-temperature high-pressure gas flooding, which adopts a glass etching model to simulate the oil-water distribution state and the fluid seepage characteristic in a micro-nano pore structure; utility model CN202022247112.0 has authorized a visual pressurized sand pack device of torsion.
However, the above-disclosed patents have major problems in that: (1) the high-temperature high-pressure visual displacement experimental device simulates the pore throat characteristics of a stratum by using etched glass, and has a large difference with the pore throat gap distribution of a real core; (2) the current visual displacement experiment of the real rock core uses a rock core thin sheet clamped in the middle of a glass sheet and uses glue to bond a pipeline to form an inlet and outlet channel, the operation can be carried out only at normal temperature and normal pressure, when the pressure exceeds 0.2MPa, the glue can be spread to destroy a sample, and the experiment can not be carried out under the conditions of high temperature and high pressure.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a real core microcosmic visual displacement system and a using method thereof under the conditions of high temperature and high pressure.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the real core microcosmic visual displacement system under the high-temperature and high-pressure condition comprises a displacement module, a temperature control module, a pressure adjusting module, a real core clamping module, a high-definition video digital processing module and an auxiliary module;
the displacement module comprises three ABC piston containers 9, 10 and 11 which are connected in parallel, and outlets of the three ABC piston containers 9, 10 and 11 are communicated with a real core model 34 in the real core clamping module through a six-way valve 14;
the temperature control module comprises a water bath circulating pump 13 and a visual clamp heating device, the water bath circulating pump 13 is communicated with water bath heating cavities arranged outside the ABC piston containers 9, 10 and 11, the visual clamp heating device comprises a flexible heating cloth protective sleeve 19 arranged on a visual clamp 17 and a temperature control regulator 20 connected with an electric heating conductor inside the flexible heating cloth protective sleeve 19;
the real core clamping module comprises a visual clamping device 17, a real core model 34 is clamped in the visual clamping device 17, the real core model 34 comprises a core piece 43 fixed on a quartz glass slide 42, the left end and the right end of the core piece 43 are respectively provided with an injection end diversion area 44 and an outlet end diversion area 45, the inlet diversion area 44 is connected with the inlet guide pipe 30, and the outlet diversion area 45 is connected with the outlet guide pipe 31; inlet conduit 30 is connected to six-way valve 14;
the visual holder 17 comprises a slice holding upper body 38 and a slice holding lower body 39, the joint of the slice holding upper body 38 and the slice holding lower body 39 is a ring pressing cavity 40 for placing the real core model 34, and the upper part and the lower part of the ring pressing cavity 40 are respectively communicated with a ring pressing upper conduit 36 and a ring pressing lower conduit 37 which can pressurize the slice holding upper body 38 and the slice holding lower body 39; sapphire glass 35 for observing the condition in the ring pressing cavity 40 is arranged on the sheet clamping upper body 38 and the sheet clamping lower body 39, and the sapphire glass 35 is fixed by a sheet clamping device pressing cap 47;
the pressure adjusting module comprises an ISCO micro-injection pump 12 and a ring pressure tracking pump 16, wherein an outlet pipeline of the ISCO micro-injection pump 12 is respectively connected with inlets at the bottoms of the three ABC piston containers 9, 10 and 11; the ring pressure tracking pump 16 is provided with two connecting pipelines, wherein one pipeline is connected with the six-way valve 14, and the other pipeline is respectively connected with the upper body 38 and the lower body 39 of the visual core holder 17 through a three-way valve 46;
the high-definition video digital processing module comprises a microscope 27 and a digital high-definition video system 26 which are arranged above the visual core holder 17, and signals of the microscope 27 and the digital high-definition video system 26 are externally connected with a computer digital image processing system 28;
the auxiliary module comprises a back-pressure valve 23, the inlet of the back-pressure valve 23 is connected with an outlet guide pipe 31 of the rock core holder 17, a pipe orifice of the back-pressure valve 23 is connected with a back-pressure pump 22 through a valve 8, the outlet end of the back-pressure valve 23 is connected with an oil-gas-water separation device 24, and a gas flowmeter 25 is connected behind the oil-gas-water separation device 24.
The use method of the real core microscopic visualization displacement system based on the high-temperature and high-pressure condition comprises the following steps:
step 1: manufacturing a real core model 34, wherein the real core model 34 consists of a quartz glass slide 42 and a real core sheet 43, sticking a real core on the quartz glass slide 42, and grinding into a real core model with a certain size according to experimental requirements;
step 2: putting a real core model 34 into a high-temperature high-pressure microscopic visual holder 17, wherein transparent rubber pads 32 and 33 are arranged above and below the real core, the transparent rubber pads 32 and 33 respectively form a cavity 40 with an upper body 38 and a lower body 39 of the visual holder, and the cavity 40 is used for injecting fluid to provide confining pressure for the real core;
and step 3: slowly injecting confining pressure liquid into the cavity 40 of the core holder at a constant flow rate by using the ring pressure tracking pump 16, exhausting air in the cavity 40 of the core holder, and controlling the pressure difference between the inlet end of the core holder and ring pressure by using the ring pressure tracking pump 16;
and 4, step 4: placing a microscope 27 above the core holder 17, and using a parallel light source 18 to polish the real core model 34 in the core holder from the side upper part, so that the fluid distribution in the real core 43 can be clearly observed through the microscope 27, the fluid flow state observed by the microscope 27 is monitored in real time through a high-definition video system 26, and the fluid flow state is stored in a computer digital image processing system 28;
and 5: crude oil used for experiments is filled into a piston container A9, mineralization water used for experiments is filled into a piston container B10, high-pressure gas used for experiments is filled into a piston container C11, and an ABC piston container is heated by a water bath circulating pump 13;
step 6: installing two flexible heating cloth protective sleeves 19 on the outer sides of an upper body 38 and a lower body 39 of the core holder, starting a heating device of the core holder, electrically heating a conductor in the protective sleeves through a temperature control regulator 20, heating the upper body 38 and the lower body 39 of the visual holder through heat conduction, and finally heating a real core model in the holder;
and 7: the ISCO micro-injection pump 12 provides displacement pressure for the ABC piston container, and a displacement medium in the ABC piston container enters the six-way valve 14 through a main pipeline and then enters the rock core holder 17 through the six-way valve 14 to displace a real rock core 34;
and 8: adding prepared mineralization water into a piston container B10, injecting the mineralization water in the piston container B10 into a real rock core model 34 by using an ISCO (ISCO) micro injection pump 12, switching a piston container A9 containing crude oil, injecting the crude oil into the real rock core model 34, and reducing the original stratum state of the real rock core;
and step 9: c piston container 11 is switched to be high-pressure gas for experiments, the back pressure pump 22 is adjusted to control the back pressure, the back pressure passes through the back pressure valve 23, the inlet and the outlet are displaced by fixed pressure difference, and gas channeling is prevented;
step 10: during the entire experiment, the ring pressure provided by the ring pressure tracking pump 16 and the inlet pressure are operated at a fixed differential pressure; ensuring that the displacement medium passes through the rock core in the displacement process, and preventing the displacement medium from passing through the upper surface and the lower surface of the real rock core;
step 11: monitoring the fluid flowing characteristics in the rock core in real time through a high-definition video system 26 in the displacement process, and stopping the displacement when the fluid in the pore throat gap space in the real rock core is not changed any more;
step 12: after the displacement experiment is finished, analyzing the experiment parameters in the whole displacement process, and analyzing and processing the acquired pictures and videos by using computer special software to finally obtain an experiment result.
Before the core piece 43 is manufactured, the gas logging permeability of the original core column is measured, and the specific formula is as follows:
Figure BDA0003616963130000051
when the expansion that occurs in the gas is isothermal,
QP＝Q o P o ＝c (2)
Figure BDA0003616963130000052
separation variable integration:
Figure BDA0003616963130000053
in the formula:
Q 0 outlet gas flow, cm 3 ；
P 0 -atmospheric pressure, MPa;
μ -viscosity of gas, mPa · s;
l is the length of the original core column, cm;
K g gas permeability, μm 2 ；
A-area of end face of original core, cm 2 ；
P 1 、P 2 Absolute pressures on the inlet and outlet end faces, MPa.
Measuring the porosity phi of the original rock core column by a saturated fluid method for the original rock core column used in the experiment:
V p ＝(m 2 -m 1 )/ρ 0 (5)
Figure BDA0003616963130000061
in the formula:
V P pore volume of original core column, cm 3 ；
m 1 、m 2 -mass of core before and after saturation of original core column, g;
ρ 0 density of fluid, g/cm 3 ；
Phi-original core column porosity;
V b total volume of original core column, cm 3 。
The real rock core model 34 is obtained by weighing the real rock core model 34 before the experiment to obtain the mass M 1 And 8, beginning to saturate the experimental fluid, and weighing the real rock core model 34 with the mass M after saturation 2 And (5) after saturation, performing step 9-step 11, developing a gas displacement experiment, and weighing the real rock core model with the mass M after displacement 3 The oil displacement efficiency eta can be calculated by the following formula;
the oil displacement efficiency is as follows:
Figure BDA0003616963130000062
according to the gas state equation:
PV＝ZnRT (8)
inquiring about the pressure P of the gas by a graphic method 0 Temperature T 0 Compression factor of Z 0 V can be observed from a constant flow pump 0 The actual state equation is as follows:
P 0 V 0 ＝z 0 nRT 0 (9)
conversion of temperature T from law of conservation of mass 0 At atmospheric pressure P 1 Volume of gas V under conditions 1 。
P 1 V 1 ＝z 1 nRT 0 (10)
Can be obtained from the above formula
Figure BDA0003616963130000071
Temperature T is obtained from the above formula 0 Volume V of gas entering real core model under condition 1 The volume of the gas at the outlet end of the back pressure valve is directly measured as V by the gas flowmeter 2 The volume of gas remaining in the real core model and dissolved in the displacement fluid is:
V＝V 1 -V 2 (12)。
the invention has the following advantages:
the invention adopts a real core model to reflect the flowing state of the fluid in the pore throat of the real core under the conditions of high temperature and high pressure, can simulate the temperature and pressure under the formation condition to truly restore the original formation condition, can observe the phase state change of the fluid and the migration characteristics of the fluid in different displacement processes by combining a high-definition digital image processing system, and can observe the whole displacement process on line to obtain the dynamic displacement process.
The invention can realize displacement experiments of various different displacement media such as gas drive, water drive, chemical drive and the like, and can observe the distribution of crude oil in a real core pore throat and the utilization degree of crude oil in different pore scales in the displacement process in real time.
Drawings
Fig. 1 is a schematic structural diagram of a high-temperature high-pressure microscopic visual displacement system according to the invention.
Fig. 2 is a schematic diagram of a core holder configuration of the present invention.
Fig. 3 is a schematic structural view of a real core model 34 of the present invention.
FIG. 4 shows high-temperature high-pressure CO in an embodiment of the present invention 2 And (4) a residual oil distribution characteristic diagram in the early stage of oil displacement.
FIG. 5 shows high-temperature high-pressure CO in an embodiment of the present invention 2 And (5) remaining oil distribution characteristic diagram after oil displacement is finished.
In the figure, 1-valve, 2-valve, 3-valve, 4-valve, 5-valve, 6-valve, 7-valve, 8-valve, 9-A piston container, 10-B piston container, 11-C piston container, 12-ISCO micro injection pump, 13-circulating water bath kettle, 14-six-way valve, 15-pressure sensor, 16-ring pressure tracking pump, 17-real core visual core holder, 18-light source, 19-flexible heating protective sleeve, 20-temperature controller, 21-pressure sensor, 22-back pressure pump, 23-back pressure valve, 24-oil-gas-water separation device, 25-gas flowmeter, 26-digital high-definition video system, 27-vertical long-focus microscope, 28-computer, 29-sealing ring, 30-inlet conduit, 31-outlet conduit, 32-transparent rubber mat, 33-transparent rubber mat, 34-real core model, 35-sapphire glass, 36-ring pressing upper conduit, 37-ring pressing lower conduit, 38-core holder upper body, 39-core holder lower body, 40-ring pressing cavity, 41-bolt, 42-glass slide, 43-core sheet, 44-inlet guide area, 45-outlet guide area, 46-three-way valve and 47-sheet holder pressing cap.
Detailed Description
The invention will be further described with reference to the accompanying drawings, to which the scope of the invention is not limited.
Referring to fig. 1, the real core microscopic visual displacement system under the high-temperature and high-pressure condition comprises a displacement module, a temperature control module, a pressure adjusting module, a real core clamping module, a high-definition video digital processing module and an auxiliary module;
the displacement module comprises three ABC piston containers 9, 10 and 11 which are connected in parallel and heated by water bath, outlets of the three ABC piston containers 9, 10 and 11 are communicated with a real core model 34 in the real core clamping module through a six-way valve 14, and inlets and outlets of the ABC piston containers 9, 10 and 11 are provided with valves 1-6;
the temperature control module comprises a water bath circulating pump 13 and a visual holder heating device, the water bath circulating pump 13 is communicated with water bath heating cavities arranged outside the ABC piston containers 9, 10 and 11, the three ABC piston containers 9, 10 and 11 can be subjected to water bath heating after the water bath circulating pump 13 is communicated with the water bath heating cavities, and the highest heating temperature is 100 ℃; the visual holder heating device comprises a flexible heating cloth protective sleeve 19 arranged on the visual holder 17 and a temperature control regulator 20 connected with an electric heating conductor inside the flexible heating cloth protective sleeve 19, the temperature of the conductor in the flexible heating cloth protective sleeve 19 is regulated through the temperature control regulator 20, then the flexible heating cloth protective sleeve 19 conducts heat conduction to heat an upper body 38 and a lower body 39 of the visual holder 17, and finally the real core model 34 in the holder is heated.
Referring to fig. 2 and 3, the real core holding module includes a visual holder 17, a real core model 34 is held in the visual holder 17, the real core model 34 includes a core piece 43 fixed on a quartz glass slide 42, an injection end diversion area 44 and an outlet end diversion area 45 are respectively arranged at the left and right ends of the core piece 43, the inlet diversion area 44 is connected with the inlet conduit 30, and the outlet diversion area 45 is connected with the outlet conduit 31; the inlet conduit 30 is connected to the six-way valve 14; when the real core model 34 is manufactured, the real core column is cut and polished to be in a specification required by a target, the manufactured core sheet 43 is fixed on the quartz glass slide 42 to form the real core model 34, then the real core model 34 is placed into the visual holder 17, the real core is clamped by the upper and lower transparent rubber cushions 32 and 33, and the visual holder is installed to form the real core holding system.
The visual holder 17 described with reference to fig. 2 comprises a slice holding upper body 38 and a slice holding lower body 39 which are connected and sealed through an inner hexagon bolt 41 and an O-shaped seal 29, the joint of the slice holding upper body 38 and the slice holding lower body 39 is a ring pressing cavity 40 for placing the real core model 34, and the upper part and the lower part of the ring pressing cavity 40 are respectively communicated with a ring pressing upper conduit 36 and a ring pressing lower conduit 37 which can press the slice holding upper body 38 and the slice holding lower body 39; a sapphire glass 35 for observing the condition in the ring pressing cavity 40 is arranged on the upper sheet clamping body 38 and the lower sheet clamping body 39, and the sapphire glass 35 is fixed by a sheet clamping pressing cap 47.
The pressure adjusting module comprises an ISCO micro injection pump 12 and a ring pressure tracking pump 16, outlet pipelines of the injection pump 12 are respectively connected with inlets at the bottoms of the three ABC piston containers 9, 10 and 11, the ISCO micro injection pump 12 mainly provides injection pressure, the ISCO micro injection pump 12 can realize two displacement modes of constant-pressure displacement and constant-speed displacement, and the injection pressure is transmitted to the ABC piston containers 9, 10 and 11 through the ISCO pumps; the ring pressure tracking pump 16 is provided with two connecting pipelines, one of the pipelines is connected with the six-way valve 14 and is used for monitoring the pressure at the inlet of the core holder, the other pipeline is respectively connected with the upper body 38 and the lower body 39 of the visual core holder 17 through the three-way valve 46, the ring pressure tracking pump 16 can simultaneously pressurize the two devices of the upper body 38 and the lower body 39 of the visual holder through the upper confining pressure pipeline 36 and the lower confining pressure pipeline 37 so as to ensure that the pressure difference of the upper edge and the lower edge of the real core model in the ring pressure cavity 40 is the same and ensure that the real core cannot be cracked due to different pressure differences. The ring pressure tracking pump 16 provides ring pressure for the visual holder 17, and can track the pressure difference between the ring pressure and the inlet end of the core holder 17 in real time.
The high-definition video digital processing module comprises a microscope 27 and a digital high-definition video system 26 which are arranged above the visual core holder 17, and signals of the microscope 27 and the digital high-definition video system 26 are externally connected with a computer digital image processing system 28. The microscope 27 is a vertical long-focus high-power microscope, the magnification can be enlarged to the micron level, the flowing rule of movable fluid in the micron-sized pore throat of a real rock core and the microscopic occurrence state of residual oil can be observed clearly, the digital high-definition video system 26 can monitor the flowing of the movable fluid in the real rock core in the whole displacement process without interruption so as to observe the migration rule of fluid in the rock core before and after displacement in the rock core in various displacement modes, and the computer digital image processing system 28 can carry out digital processing on shot high-definition images and video files and calculate the displacement efficiency and the residual oil distribution in a shooting area.
The auxiliary module includes back pressure valve 23, back pressure valve 23 import and the export pipe 31 of core holder 17 are connected, still be provided with valve 7 on the pipeline, a back pressure valve 23 mouth of pipe passes through valve 8 and connects back pressure pump 22, need increase back pressure through back pressure pump 22 and make the interior exit pressure of core holder 17 carry out the core displacement with fixed displacement pressure differential at the displacement in-process, back pressure valve 23 exit end is connected with oil gas water separator 24, connect gas flowmeter 25 behind oil gas water separator 24, with monitoring oil gas water's output and the oil displacement efficiency at whole displacement in-process.
Below with CO 2 The actual sandstone is displaced as an example, and the specific experimental process of the actual core microscopic visual displacement system and the using method under the high-temperature and high-pressure conditions is explained.
(1) Selecting a rock core of a reservoir with 6 Erdos basin lengths, washing and drying the rock sample, and measuring the cross section diameter D, the rock core length L and the inlet pressure P of the used rock core 1 Outlet pressure P 2 At atmospheric pressure P 0 Flow rate Q 0 Gas viscosity mu is 0.01772mPa s, the permeability of the rock core is calculated by using a gas permeability measuring method, and the concrete measurement is carried outThe parameters are shown in the following table.
Number of times L(cm) D(cm) A(cm 2 ) P 0 (MPa) P 1 (MPa) P 2 (MPa) Q 0 (ml/s)
For the first time 6.35 2.43 4.635 0.1 0.68 0.1 0.170
For the second time 6.35 2.43 4.635 0.1 0.67 0.1 0.173
The third time 6.35 2.43 4.635 0.1 0.68 0.1 0.172
By the formula
Figure BDA0003616963130000111
Figure BDA0003616963130000112
The third permeability of the core is respectively as follows: k g1 ＝1.25×10 -3 μm 2 ，K g2 ＝1.31×10 -3 μm 2 ，K g3 ＝1.26×10 -3 μm 2 The final permeability of the core was 1.27 × 10 -3 μm 2 。
The porosity phi of the core used in the experiment is measured by a saturated fluid method:
m 1 (g) m 2 (g) A(cm 2 ) L(cm) V b (cm 3 )
74.87 79.25 4.635 6.35 29.4
V p ＝(m 2 -m 1 ) (3)
Figure BDA0003616963130000113
crude oil density ρ 0 Is 0.861g/cm 3 ；
The porosity was found to be 14.8%.
(2) Re-washing the core column with oil, grinding into core slices 43 with the length of 60mm, the width of 23mm and the thickness of 1mm, adhering the core slices on a quartz glass slide 42, carving flow guide areas 44 and 45 with the lengths of 18mm and the widths of 2mm on the left and right sides of the core to prepare a real core model 34, and weighing the weight M 1 It was 7.53 g.
(3) Putting a real core model 34 into a high-temperature high-pressure microscopic visual holder 17, wherein the upper part of the real core model 34 is provided with a transparent rubber cushion 32, the lower part of the real core model is provided with a transparent rubber cushion 33, the real core model 34 is wrapped, a sealing ring 29 is arranged between an upper body 38 and a lower body 39 of the core holder to seal the core holder 17 through an inner hexagon bolt 41;
(4) injecting liquid into the cavity 40 from the ring pressure upper conduit 36 and the ring pressure lower conduit 37 at a constant flow rate through a three-way valve 46 by using a ring pressure tracking pump 16, wherein the pressure at the upper part and the lower part of the cavity is the same to provide confining pressure for the real core model 34, slowly injecting confining pressure liquid into the cavity 40 of the core holder, discharging air in the cavity 40 of the core holder, controlling the pressure difference between the inlet end and the ring pressure of the core holder by using the ring pressure tracking pump 16, installing a flexible heating protective sleeve 19 on the outer sides of the upper body 38 and the lower body 39 of the core holder, and starting a temperature controller 20 to control the temperature to be 60 ℃ to heat the core holder 17;
(5) dyeing experimental crude oil with oil red, dyeing mineralization water used in the experiment with methyl blue, loading the crude oil into a piston container 9A, loading the mineralization water into a piston container 10B, and loading CO used in the experiment 2 Gas is filled into the C piston container 11, the circulating water bath kettle 13 is started, and the ABC piston containers 9, 10 and 11 are heated at the set temperature of 60 ℃;
(6) connecting all experimental equipment according to a flow chart, turning on a light source 18, a microscope 27, a high-definition video system 26 and a computer 28, continuously recording real cores 34 in a core holder 17 in the whole displacement process, turning on a six-way valve switch of a valve 2, a valve 5, a valve 7 and a connecting pipeline, turning off the valve 1, the valve 3, the valve 4 and the valve 6, setting the flow rate of an ISCO micro-injection pump 12 to be 0.001ml/min, setting the mode of a ring pressure tracking pump 16 to be a tracking mode, pressurizing by using the confining pressure higher than the inlet end pressure by 2MPa, starting to saturate mineralized water for the real cores, and stopping the displacement when 3PV mineralized water is collected by a gas-liquid separation device 24;
(7) closing the valve 2 and the valve 5, opening the valve 1 and the valve 4, saturating crude oil in the real rock core in the same way, stopping displacement when the liquid at the outlet end of the gas-liquid separation device is 100% crude oil, and reducing the original stratum state of the real rock core at the moment;
(8) closing the six-way valve 14 and the valve 7 connected with the inlet end of the core holder, unloading inlet pressure through the six-way valve 14, unloading confining pressure through the ring pressure tracking pump 16, opening the core holder and weighing the weight M of the real core model 2 The weight of the core holder is 8.49g, the core holder is installed after weighing, and the core holder is communicated with experimental equipment;
(9) closing the valve 1, opening the valve 4, opening the valve 3, setting the flow rate of the ISCO micro-injection pump 12 to be 10ml/min, pressurizing the gas in the C piston container 11, stopping injection when the pressure is increased to 8MPa, and suspending the ISCO micro-injection pump 12;
(10) pressurizing the back pressure pump 22, setting the back pressure to be 6MPa, and displacing by using the pressure difference of 2MPa at an inlet and an outlet;
(11) opening ISCO micro injection pump 12, performing displacement at constant pressure of 8MPa, opening valve 6, pipeline valve with inlet end of core holder 17 connected with six-way valve, and starting CO at 8MPa 2 Displacing crude oil, taking pictures and recording real cores in real time, and recording output liquid in the gas-liquid-water separator 24 in real time;
(12) FIG. 4 shows CO 2 In the initial stage of crude oil displacement, namely 10 hours of displacement, the real core slice 43 is photographed by a digital high-definition video system 26 through a vertical long-focus high-power microscope, the magnification is 2 times, the displacement can be seen from the displacement direction, the displacement is from left to right, the red color on the left side in the picture is relatively shallow, the situation that most of the crude oil at the position is driven is shown, two large high-permeability channels are arranged on the right side, and CO in the initial stage of the displacement is detected 2 Mainly flows along the hypertonic channel, and the residual red color is the distribution of the residual oil in the early stage.
(13) FIG. 5 shows CO 2 When the crude oil displacement is finished, namely 40 hours of the crude oil displacement, the real core slice 43 is photographed, the magnification factor is 2 times, and the large-area red area becomes white, which indicates that most of the crude oil in the pores is displaced, only the crude oil in the dead pores can not be displaced, and the residual red is the distribution of the residual oil after the crude oil displacement is finished.
(14) Observing the residual oil distribution in the real rock core through a high-definition video system, stopping displacement when the oil-gas distribution in the rock core does not change for a long time, and recording the accumulated injection volume V on a display screen of an ISCO (interference signal processor) advection pump 0 0.65ml, the cumulative gas quantity V of the gas flowmeter 2 When the volume is 865ml, closing all equipment, opening a six-way valve emptying displacement pressure, opening an annular pressure tracking pump emptying valve, emptying annular pressure, and removing the core holder after the temperature of the core holder is reduced to normal temperature and the core holder is cooled for a long time; weighing mass M of real core model 3 9.12 g;
from the formula of oil displacement efficiency
Figure BDA0003616963130000131
The oil displacement efficiency is 65.6 percent
Checking by a plate method to obtain CO at 60 ℃ and 8MPa 2 By a compression factor Z 0 Is 0.65, a compression factor Z at atmospheric pressure 1 Is 1; p 0 Is 8MPa, P 1 Is 0.101 MPa;
according to the gas state equation:
PV＝ZnRT (6)
the actual state equation is as follows:
P 0 V 0 ＝Z 0 nRT 0 (7)
from the law of conservation of mass, the temperature T can be converted 0 At atmospheric pressure P 1 Gas volume under conditions V 1
P 1 V 1 ＝Z 1 nRT 0 (8)
From the above formula
Figure BDA0003616963130000141
Get V 1 ＝792ml
The volume of gas retained in the core and dissolved in the displacement fluid is:
V＝V 1 -V 2 (12)
get V73 ml
(15) And cleaning the whole set of experimental equipment, and processing the experimental result.

Claims (6)

1. The real core microscopic visual displacement system under the high-temperature and high-pressure condition is characterized by comprising a displacement module, a temperature control module, a pressure adjusting module, a real core clamping module, a high-definition video digital processing module and an auxiliary module;
the displacement module comprises three ABC piston containers (9, 10 and 11) connected in parallel, and outlets of the three ABC piston containers (9, 10 and 11) are communicated with a real core model (34) in the real core clamping module through a six-way valve (14);
the temperature control module comprises a water bath circulating pump (13) and a visual holder heating device, the water bath circulating pump (13) is communicated with a water bath heating cavity arranged outside the ABC piston container (9, 10 and 11), the visual holder heating device comprises a flexible heating cloth protective sleeve (19) arranged on the visual holder (17) and a temperature control regulator (20) connected with an electric heating conductor inside the flexible heating cloth protective sleeve (19);
the real core clamping module comprises a visual clamping device (17), and a real core model (34) is clamped in the visual clamping device (17);
the pressure regulating module comprises an ISCO micro injection pump (12) and a ring pressure tracking pump (16), and outlet pipelines of the injection pump (12) are respectively connected with inlets at the bottoms of the three ABC piston containers (9, 10 and 11); the ring pressure tracking pump (16) is provided with two connecting pipelines, wherein one pipeline is connected with the six-way valve (14), and the other pipeline is respectively connected with the upper body (38) and the lower body (39) of the visual core holder (17) through a three-way valve (46);
the high-definition video digital processing module comprises a microscope (27) and a digital high-definition video system (26) which are arranged above the visual core holder (17), and signals of the microscope (27) and the digital high-definition video system (26) are externally connected with a computer digital image processing system (28);
the auxiliary module comprises a back-pressure valve (23), the inlet of the back-pressure valve (23) is connected with an outlet guide pipe (31) of the rock core holder (17), a pipe opening of the back-pressure valve (23) is connected with a back-pressure pump (22) through a valve (8), the outlet end of the back-pressure valve (23) is connected with an oil-gas-water separation device (24), and a gas flowmeter (25) is connected behind the oil-gas-water separation device (24).
2. The real core microscopic visual displacement system under the high-temperature and high-pressure condition as claimed in claim 1, wherein the real core model (34) comprises a core piece (43) fixed on a quartz glass slide (42), the left and right ends of the core piece (43) are respectively provided with an injection end flow guide area (44) and an outlet end flow guide area (45), the inlet flow guide area (44) is connected with the inlet guide pipe (30), and the outlet flow guide area (45) is connected with the outlet guide pipe (31); the inlet conduit (30) is connected to the six-way valve (14).
3. The microscopic visualization displacement system for the real core under the high temperature and high pressure conditions as claimed in claim 1, wherein the visualization holder (17) comprises a slice holding upper body (38) and a slice holding lower body (39), the joint of the slice holding upper body (38) and the slice holding lower body (39) is an annular pressing cavity (40) for placing the real core model (34), and an annular pressing upper conduit (36) and an annular pressing lower conduit (37) which can pressurize the slice holding upper body (38) and the slice holding lower body (39) are respectively communicated with the upper part and the lower part of the annular pressing cavity (40); sapphire glass (35) for observing the condition in the annular pressing cavity (40) is arranged on the sheet clamping upper body (38) and the sheet clamping lower body (39), and the sapphire glass (35) is fixed through a sheet clamping pressing cap (47).
4. The use method of the real core microscopic visualization displacement system under the high-temperature and high-pressure condition is characterized by comprising the following steps of:
step 1: manufacturing a real core model (34), wherein the real core model (34) consists of a quartz glass slide (42) and a real core piece (43), sticking the real core on the quartz glass slide (42), and grinding into a real core model with a certain size according to experimental requirements;
step 2: placing a real core model (34) into a high-temperature high-pressure microscopic visual holder (17), wherein transparent rubber pads (32, 33) are arranged on the upper part and the lower part of the real core, the transparent rubber pads (32, 33) respectively form a cavity (40) with an upper body (38) and a lower body (39) of the visual holder, and the cavity (40) is used for injecting fluid to provide confining pressure for the real core;
and step 3: slowly injecting confining pressure liquid into the cavity (40) of the core holder at a constant flow rate by using an annular pressure tracking pump (16), exhausting air in the cavity (40) of the core holder, and controlling the pressure difference between the inlet end of the core holder and annular pressure by using the annular pressure tracking pump (16);
and 4, step 4: placing a microscope (27) above a core holder (17), and using a parallel light source (18) to polish a real core model (34) in the core holder from the side upper side, so that the fluid distribution in a real core (43) can be clearly observed through the microscope (27), the fluid flow state observed by the microscope (27) is monitored in real time through a high-definition video system (26), and the fluid flow state is stored in a computer digital image processing system (28);
and 5: crude oil used for experiments is filled into a piston container (9) A, mineralization water used for experiments is filled into a piston container (10) B, high-pressure gas used for experiments is filled into a piston container (11) C, and an ABC piston container (9, 10, 11) is heated by a water bath circulating pump (13);
step 6: installing two flexible heating cloth protective sleeves (19) on the outer sides of an upper body (38) and a lower body (39) of a core holder, starting a core holder heating device, electrically heating a conductor in the protective sleeves through a temperature control regulator (20), heating the upper body (38) and the lower body (39) of the visual holder through heat conduction, and finally heating a real core model in the holder;
and 7: an ISCO micro injection pump (12) provides displacement pressure for an ABC piston container, and displacement media in the ABC piston container enter a six-way valve (14) through a main pipeline and then enter a core holder (17) through the six-way valve (14) to displace a real core (34);
and 8: adding prepared mineralization water into a piston container B (10), injecting the mineralization water in the piston container B (10) into a real core model (34) by using an ISCO (ISCO) micro injection pump (12), switching a piston container A (9) containing crude oil, injecting the crude oil into the real core model (34), and reducing the original stratum state of the real core;
and step 9: c, a piston container (11) is switched to be high-pressure gas for experiments, a back pressure pump (22) is adjusted to control back pressure, and the back pressure is replaced by a fixed pressure difference through a back pressure valve (23) to prevent gas channeling;
step 10: during the whole experiment, the ring pressure provided by the ring pressure tracking pump (16) and the inlet pressure are operated at a fixed pressure difference; ensuring that the displacement medium passes through the rock core in the displacement process, and preventing the displacement medium from passing through the upper surface and the lower surface of the real rock core;
step 11: monitoring the fluid flowing characteristics in the rock core in real time through a high-definition video system (26) in the displacement process, and stopping the displacement when the fluid in the pore throat gap space in the real rock core is not changed any more;
step 12: after the displacement experiment is finished, analyzing the experiment parameters in the whole displacement process, and analyzing and processing the acquired pictures and videos by using computer special software to finally obtain an experiment result.
5. The use method of the real core microscopic visualization displacement system under the high temperature and high pressure condition as claimed in claim 4, wherein,
before the core slice (43) is manufactured, the gas logging permeability of an original core column is measured, and the specific formula is as follows:
Figure FDA0003616963120000041
when the expansion that occurs in the gas is isothermal,
QP＝Q o P o ＝c (2)
Figure FDA0003616963120000042
integration of the separation variables:
Figure FDA0003616963120000043
in the formula:
Q 0 outlet gas flow, cm 3 ；
P 0 -atmospheric pressure, MPa;
μ -viscosity of the gas, mPas;
l is the length of the original core column, cm;
K g gas permeability, μm 2 ；
A-area of end face of original core, cm 2 ；
P 1 、P 2 Absolute pressures on the inlet and outlet end faces, MPa;
measuring the porosity phi of the original rock core column by a saturated fluid method for the original rock core column used in the experiment:
V p ＝(m 2 -m 1 )/ρ 0 (5)
Figure FDA0003616963120000051
in the formula:
V P pore volume of original core column, cm 3 ；
m 1 、m 2 -mass of core before and after saturation of original core column, g;
ρ 0 density of fluid, g/cm 3 ；
Phi-original core column porosity;
V b total volume of original core-pillar, cm 3 。
6. The use method of the real core microscopic visualization displacement system under the high temperature and high pressure condition as claimed in claim 4, wherein,
the real rock core model (34) is obtained by weighing the real rock core model (34) with the mass M before the experiment 1 And 8, beginning to saturate the experimental fluid, and weighing the real rock core model (34) with the mass M after saturation 2 And after the saturation is finished, performing the steps 9-11, developing a gas displacement experiment, and after the displacement is finished, weighing the mass of the real rock core model to be M 3 The oil displacement efficiency eta can be calculated by the following formula;
the oil displacement efficiency is as follows:
Figure FDA0003616963120000061
according to the gas state equation:
PV＝ZnRT (8)
by checking the gas pressure P by means of a graphic method 0 Temperature T 0 Compression factor of Z 0 Can be observed from a constant flow pump to obtain V 0 The actual state equation is as follows:
P 0 V 0 ＝Z 0 nRT 0 (9)
conversion of temperature T from law of conservation of mass 0 At atmospheric pressure P 1 Gas volume under conditions V 1 ；
P 1 V 1 ＝Z 1 nRT 0 (10)
Can be obtained from the above formula
Figure FDA0003616963120000062
Temperature T is obtained from the above formula 0 Volume V of gas entering into real core model under condition 1 The volume of the gas at the outlet end of the back pressure valve is directly measured as V by the gas flowmeter 2 The volume of gas remaining in the real core model and dissolved in the displacement fluid is:
V＝V 1 -V 2 (12)。
CN202210446144.4A 2022-04-26 2022-04-26 Real core microcosmic visual displacement system under high-temperature and high-pressure conditions and use method Pending CN115032192A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116148154A (en) * 2023-01-06 2023-05-23 中国科学院地质与地球物理研究所 Experimental device and interpretation method for simulating core seepage heat and mass transfer under high temperature and high pressure

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116148154A (en) * 2023-01-06 2023-05-23 中国科学院地质与地球物理研究所 Experimental device and interpretation method for simulating core seepage heat and mass transfer under high temperature and high pressure
CN116148154B (en) * 2023-01-06 2023-09-19 中国科学院地质与地球物理研究所 Experimental device and interpretation method for simulating core seepage heat and mass transfer under high temperature and high pressure

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