CN113358542A - Device and method for testing fluid displacement efficiency in different pore throat size ranges - Google Patents
Device and method for testing fluid displacement efficiency in different pore throat size ranges Download PDFInfo
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Abstract
The invention discloses a device and a method for testing fluid displacement efficiency in different pore throat size ranges, wherein the device comprises a fluid displacement system, a fluid measurement system, a flow metering system and a pressure pipeline; the fluid displacement system comprises a high-pressure injection pump and a middle water container for storing heavy water, the fluid measuring system comprises a rock core holder, a nuclear magnetic resonance analyzer and a manual confining pressure pump, the rock core holder is positioned in the nuclear magnetic resonance analyzer, and the fluid measuring system comprises a transparent glass tube and a measuring cylinder. The device is insensitive to the change of external conditions, does not need to take out a sample and then carry out nuclear magnetic resonance testing, has higher accuracy of experimental testing, and can provide technical support and theoretical guidance for the development of oil and gas reservoirs. The method has simple and convenient operation, adopts the nuclear magnetic resonance on-line displacement method, has high precision and low signal interference, can accurately measure the fluid displacement efficiency and obtain the T2Spectral scanning and nuclearAnd the accuracy of the experimental result is improved by the magnetic resonance imaging result.
Description
Technical Field
The invention relates to the technical field of hydrodynamics, in particular to a device and a method for testing fluid displacement efficiency in different pore throat size ranges.
Background
In recent years, various visualization techniques (such as magnetic resonance imaging and three-dimensional CT imaging) have been combined with ideal homogeneous porous media experiments (such as glass bead and microfluidic cell experiments) to provide visualization kinetics of invasive fluids. However, in tight sandstone reservoirs, the strong heterogeneity and small pore throat size complicate the dynamic behavior of the invading fluid and the unmiscible displacement process. Due to poor displacement stability, the displacement efficiency of a heterogeneous pore system is lower than that of a homogeneous pore system. Furthermore, the surface chemistry of pore channels can affect the affinity between solid and fluid molecules, making the ideal model unsuitable for studying the invasion mechanism of immiscible fluids in tight sandstones.
In view of the above problems, the nuclear magnetic resonance technology is a non-destructive research means and can accurately reveal the occurrence relationship of fluid in pores, and its importance in the petroleum industry has been increasing year by year in recent years. The nuclear magnetic pore diameter measurement is performed by taking water molecules (hydrogen-containing nuclei) as probes, the minimum pore throat at the nanometer level can be measured, and only when the pore diameter of the water molecules is too small, the nuclear magnetic signals are slightly lost due to too fast relaxation. At present, the nuclear magnetic resonance test mode of the fluid displacement experiment is mainly off-line test, namely after the experiment is finished, the rock core is taken out of the holder and then nuclear magnetic resonance scanning is carried out. Because the nuclear magnetic resonance equipment is very sensitive to the change of the external environment, the nuclear magnetic resonance test is carried out after the sample is taken out, so that larger experimental error is easily caused, and the accuracy of the test result is influenced. At present, scholars at home and abroad develop some online nuclear magnetic resonance measurement experimental devices, but the devices are not widely applied due to the defects of complex structure, difficult operation, nuclear magnetic signal interference and the like. Therefore, there is a need to design and develop an apparatus and method for testing nuclear magnetic resonance, which is easy to operate, has low signal interference and accurate test results.
Disclosure of Invention
In order to solve the problems in the prior art, the invention providesA device and a method for testing the displacement efficiency of fluids in different pore throat size ranges can obtain the displacement efficiency and nuclear magnetic temperature T of the fluids in different pore throat size ranges under different conditions2The spectrum change condition, the device operation is convenient, the accuracy is high, and the device can be used for calculating the fluid displacement efficiency in different pore throat size ranges, thereby solving the problems mentioned in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
an apparatus for testing fluid displacement efficiency across different pore throat dimensions, the apparatus comprising a fluid displacement system, a fluid measurement system, a flow metering system and a pressure line for interfacing; the fluid displacement system comprises a high-pressure injection pump and a middle water container for storing heavy water, the fluid measuring system comprises a rock core holder, a nuclear magnetic resonance analyzer and a manual confining pressure pump, the rock core holder is connected with the nuclear magnetic resonance analyzer 1 through a pressure pipeline, and the fluid measuring system comprises a transparent glass tube and a measuring cylinder.
Preferably, one end of the intermediate water container is connected with the high-pressure injection pump, and the other end of the intermediate water container is in threaded connection with the communication part at the side end of the core holder.
Preferably, the core holder comprises a hollow rubber barrel with metal kettle covers at two ends, a rubber ring is further arranged in the core holder, fluid can only flow to the end face along the throat and cannot seep to the side surface of the rock sample, the rock sample can be completely sealed after the rubber ring is heated, a metal shell is arranged on the outer surface of the core holder, the metal shell is fixedly connected with a fixed supporting device, the fixed supporting device enables the position of the core holder to be kept fixed, and the core holder is prevented from shaking.
Preferably, the other end of the core holder is connected with a manual confining pressure pump, and the manual confining pressure pump is used for applying constant pressure to two ends of the core.
Preferably, a uniflow valve and a pressure gauge are further arranged between the intermediate water container and the core holder; the uniflow valve is used for controlling the flow and the speed of fluid, and the pressure gauge is used for acquiring the pressure conditions of two ends of the rock core and water flooding.
Preferably, the measuring cylinder is used for directly reading the discharged oil quantity, and the scale value of the measuring cylinder is accurate to 1 ml.
Preferably, the pressure pipeline is made of stainless steel materials, so that corrosion of the pressure pipeline caused by flowing liquid is prevented.
A method for testing fluid displacement efficiency within different pore throat size ranges comprises the following steps:
s1, placing the saturated oil sample into a core holder;
s2, applying constant confining pressure to the core holder by using a manual confining pressure pump; and nuclear magnetic resonance T under the confining pressure2The spectral curve is used as reference, and the pore distribution range of the sample can be obtained quantitatively;
s3, under constant pressure, injecting heavy water into the core through a middle water container by using a high-pressure injection pump, and driving white oil out of the core;
s4, quantitatively measuring accumulated oil production and water production through a metering system connected to the lower end of the core holder, increasing the displacement of reservoir oil along with the increase of injection time, stopping injecting heavy water until the oil mass on the outlet side is not increased any more, storing related experimental data, and acquiring the nuclear magnetic resonance T of water displacement under different capillary numerical control through a nuclear magnetic resonance analyzer2And mapping to obtain the displacement efficiency.
Preferably, the preparation of the saturated oil sample in the step S1 specifically comprises: cleaning and drying the sample to remove residual formation water, hydrocarbon fluid and salt, then aging the sample to keep the original wettability of the core, then applying vacuum to the sample, and saturating the sample with white oil under constant pressure until the sample is completely saturated to obtain a saturated oil sample.
Preferably, the sample is saturated with white oil at constant pressure for 48h, the viscosity of white oil μ o being 5mpa · s.
The invention has the beneficial effects that: the device is insensitive to the change of external conditions, does not need to take out a sample and then carry out nuclear magnetic resonance test, has higher accuracy of experimental test, and can be used for opening oil and gas reservoirsThe device is simple and convenient to operate, reasonable in method, and significant in mastering and controlling a water flooding dominant channel, inhibiting unstable interface flow, improving water flooding efficiency and the like. The method has simple and convenient operation, adopts the nuclear magnetic resonance on-line displacement method, has high precision and low signal interference, can accurately measure the fluid displacement efficiency and obtain the T2The method has repeatability, can be used for carrying out repeated research under the same experimental conditions, and can also adopt a controlled variable research method to change one of the conditions and research the influence and change rule of the controlled variable research on the displacement efficiency.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
FIG. 2 is a schematic view of a core holder according to the present disclosure;
FIG. 3 is a schematic view of the structure of the intermediate water container of the present invention;
FIG. 4 shows the nuclear magnetic resonance T of core sample J305-3 under different capillary numerical control for water flooding2The atlas (a) is a water displacement nuclear magnetic resonance T2 atlas of the rock core sample J305-3 under the displacement pressure of 3MPa, (b) is a water displacement nuclear magnetic resonance T2 atlas of the rock core sample J305-3 under the displacement pressure of 10MPa, and (c) is a water displacement nuclear magnetic resonance T2 atlas of the rock core sample J305-3 under the displacement pressure of 15 MPa;
in the figure, 1-nuclear magnetic resonance analyzer; 2-a pressure line; 3-a transparent glass tube; 4-a core holder; 5-measuring cylinder; 6-a single flow valve; 7-a pressure gauge; 8, manually surrounding and pressing the pump; 9-a base; 10-a middle water container; 11-high pressure injection pump; 12-a rubber ring; 13-a metal housing; 14-connecting screw threads; 15-fixing the support device; 16-metal kettle cover; 17-heavy water; 18-shim.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-4, the present invention provides a technical solution: an apparatus for testing fluid displacement efficiency over a range of different pore throat sizes, the apparatus being as shown in figure 1 in block diagram form, the apparatus comprising a fluid displacement system, a fluid measurement system, a flow metering system and a pressure line 2 for connection; the fluid displacement system comprises a high-pressure injection pump 11 and a middle water container 10 for storing heavy water, the fluid measuring system comprises a rock core holder 4, a nuclear magnetic resonance analyzer 1 and a manual confining pressure pump 8, the rock core holder 4 is located inside the nuclear magnetic resonance analyzer 1, and the fluid measuring system is composed of a transparent glass tube 3 and a measuring cylinder 5.
The device utilizes white oil to saturate the rock core, then utilizes a high-pressure injection pump to inject heavy water into the rock core through a middle water container, and replaces the white oil on the wetting surface until the state of residual oil is reached. Directly reading the discharged oil and water amount by using a measuring cylinder, and obtaining the nuclear magnetic resonance T of the water flooding oil through a nuclear magnetic resonance analyzer2And (4) mapping. In addition, the manual confining pressure pump can be used for providing constant confining pressure for the core holder, so that the influence of the change of external environment factors on an experimental result is eliminated, and the fluid displacement efficiency in different pore throat size ranges can be tested.
Further, a nuclear magnetic resonance analyzer (MesoMR23-070H-I) is used for testing transverse relaxation time and T in the water flooding process2Cutting to obtain T of the core2And (4) obtaining a spectrum to obtain the average oil saturation and the displacement efficiency of the rock core.
Further, one end of the intermediate water container 10 is connected with a high-pressure injection pump 11, and the other end is connected with a communication thread 14 at the side end of the core holder 4(TCWC-15 a). The high pressure injection pump 11 can provide accurate and reliable liquid delivery, and besides standard configuration, the high pressure injection pump can also provide a proper high pressure plunger pump for experiments according to self requirements, such as flow rate, pressure, pipe orifice size, software and the like. The core holder plays a role in fixing and supporting the core. The metal kettle covers 16 and the gaskets 18 at the two end parts of the intermediate water container have the sealing effect to prevent the overflowing of the internal liquid, and the structure of the intermediate water container is shown in figure 3, so that the sealing performance of the intermediate water container is better. And filling heavy water in the intermediate water container, and displacing oil saturated in the rock core by using the heavy water. Wherein, the heavy water is water containing deuterium and oxygen isotopes, which well shields hydrogen signals in nuclear magnetic resonance and does not generate resonance. Meanwhile, due to the chemical stability and the thermal oxidation stability of the heavy water, the heavy water does not interact with rock materials or white oil, so that oil displacement in the pore throat can be detected through an instrument.
Further, the core holder structure is as shown in fig. 2, the core holder 4 is composed of a hollow rubber barrel with metal kettle covers 16 at two ends, a rubber ring 12 is further arranged in the core holder, fluid can only flow to the end face along the throat and cannot seep to the side surface of the rock sample, the rock sample can be completely sealed after the rubber ring is heated, a metal shell 13 is arranged on the outer surface of the core holder, a fixed supporting device 15 is fixedly connected with the metal shell, the position of the core holder is kept fixed by the fixed supporting device, and errors of experimental results caused by shaking of the core holder are avoided.
Furthermore, the other end of the core holder is connected with a manual confining pressure pump 8(SYL-19), the manual confining pressure pump is used for applying constant pressure to the two ends of the core, and the manual confining pressure pump is provided with a base which is used for placing and placing the manual confining pressure pump.
Furthermore, a uniflow valve 6 and a pressure gauge 7 are also arranged between the intermediate water container and the core holder; the single flow valve is used for controlling the flow and the speed of the fluid and can ensure that the experiment development can be carried out under various conditions. The pressure gauge is used for acquiring the pressure conditions of two ends of the rock core and the oil-water displacement so as to maintain the pressure of the two ends of the rock core stable.
Furthermore, the measuring cylinder 5 is used for directly reading the discharged oil amount, and the scale value of the measuring cylinder 5 is accurate to 1ml (errors caused by inaccurate reading to an experimental result are prevented), so that the change of residual oil in different pore ranges under different displacement pressures along with the displacement time can be monitored.
Furthermore, the pressure pipeline 2 is made of stainless steel materials, so that corrosion to the pressure pipeline caused by flowing liquid is prevented.
A method for testing fluid displacement efficiency within different pore throat size ranges comprises the following steps:
s1, placing the saturated oil sample into a core holder;
s2, applying constant confining pressure to the core holder by using a manual confining pressure pump (so as to prevent pore deformation and cause experimental errors); and nuclear magnetic resonance T under the confining pressure2In this state, the measured NMR T is taken as a reference2The spectral curve reflects the distribution state and the number of the radius of each communicated pore of the sample in the overlying strata state, and the pore distribution range of the sample can be obtained quantitatively;
s3, injecting heavy water 17 into the core through the intermediate water container 10 by using the high-pressure injection pump 11 under constant pressure, and driving the white oil out of the core;
s4, quantitatively measuring accumulated oil production and water production through a metering system connected to the lower end of the core holder, increasing the displacement of reservoir oil along with the increase of injection time, stopping injecting heavy water until the oil mass on the outlet side is not increased any more, storing related experimental data, and acquiring the nuclear magnetic resonance T of water displacement under different capillary numerical control through a nuclear magnetic resonance analyzer2And mapping to obtain the displacement efficiency.
Prior to the experiment, the analytical samples were washed and dried to remove residual formation water, hydrocarbon fluids and salts. And then, carrying out aging treatment on the sample twice to ensure that the core keeps the original wettability. A vacuum was applied to the samples prior to the experiment. The sample was saturated with white oil at constant pressure for 48h until complete saturation to give a saturated oil sample.
In the core water flooding experiment, two-phase unmixed phase displacement is carried out by adopting white oil (viscosity mu o is 5mpa · s) and heavy water (heavy water; mu w is 1mpa · s), and a core sample is sealed by a plastic heat shrinkage tube and placed in a rubber barrel.
The working principle of the invention is as follows: sealing a saturated oil sample in a rock core holder of a nuclear magnetic resonance analyzer, and heating a rubber ring of the holder to finish the operationAnd is fully sealed so that fluid can only flow along the throat to the end face and cannot seep to the rock sample side surface. Performing rapid positioning scanning by using a nuclear magnetic resonance analyzer, adjusting the core to the center of an imaging window, obtaining a core image in a saturated oil state, and testing and recording the T (core saturated oil) in the state2Spectra. Displacing oil phase in the core with heavy water at constant pressure, and simultaneously recording T of the core at different stages2And (4) spectral line characteristics. During the experiment, the confining pressure was kept constant until no more oil was driven out.
The device is a device which is designed by developing a fluid-fluid displacement experiment under the control of capillary numerical control of different orders of magnitude by utilizing a nuclear magnetic resonance technology in order to explore the control and influence of the capillary number on a compact reservoir multiphase flow dominant channel, and obtains the displacement efficiency and the T corresponding to the device under constant pressure2Quantitative description displacement mode index data such as cutoff value, average oil saturation and residual oil film thickness, and the like, and the change rule of the dense oil two-phase flow dominant channel is proved on the basis. The research result can provide a design principle for immiscible displacement characteristics required by the novel porous medium, and has great significance for mastering and controlling a water flooding dominant channel, inhibiting unstable flow of an interface, improving water flooding efficiency and the like.
One dimension of the thinking of the invention is the dominant channel, and the dominant channel is always the focus of attention and research in the engineering and academic circles at home and abroad due to the wide application of the dominant channel, so that the research on the dominant channel in the current industry is mainly focused on the dynamic flow of fluids such as conventional reservoir oil and gas, fracture-cavity oil reservoirs, unconsolidated sandstones and the like, and the recognition and influence factor research on the dominant channel in the oil-water two-phase seepage process of a compact reservoir is rarely reported. Experiments are carried out through the device, the influence of the capillary number Ca on the change of the dominant channel in the water flooding process of the compact oil reservoir can be obtained, but the conclusion is slightly deviated from that obtained by a traditional Critical Path Analysis (CPA). The CPA analysis method only considers the influence of a larger pore throat space. When Ca is small, capillary force is dominant, and the invading fluid flows in the direction of the larger throat under the capillary force, and as Ca increases, the total length of the critical path becomes too large so that the viscous resistance becomes too large, so that the flow rate of the fluid in the path of the larger throat decreases and the invading fluid flows in the direction of the decrease in the viscous resistance. In the above research, the percolation path from the ideal model to the heterogeneous porous medium is affected and controlled by Ca, but at present, no experimental device is available to prove how the gradually changing Ca affects the dominant path of two-phase flow in the tight oil reservoir.
The device can utilize heavy water and heavy oil to carry out a two-phase immiscible-phase oil displacement experiment under the conditions of low Ca, medium Ca and high Ca, and combines the nuclear magnetic resonance technology to know how the flow process of immiscible fluid in a compact reservoir affects and controls the dominant channel, and the change rule of the dominant channel of the two-phase flow of the compact oil is ascertained, so that the distribution rule of the residual oil is obtained.
And (3) experimental verification: the influence of different capillary numbers of the tight oil reservoir on the experimental results. At three displacement pressures P ═ 3MPa, 10MPa, and 15MPa, the T corresponding to different waterflooding times for each sample was recorded2Graph curves. About 13-19 times of T with different time intervals are collected in each water injection experiment according to the difference between the pore throat structure and the oil-water displacement amount2Graph curves. Wherein, T2The integral of the curve over the whole frequency spectrum reflects the saturation of pore fluid in the non-miscible displacement process, so that the oil displacement efficiency of each time period can be calculated. Furthermore, since heavy water has no hydrogen nuclei, T2The curve can understand the change of the residual oil saturation along with the transverse relaxation time and record T according to each time2Spectral curve and initial saturated oil T2The area difference of the spectral curve and the abscissa can deduce the fluid recovery ratio of pores with different sizes.
In sample J305-3, saturated oil and nuclear magnetism T were displaced at constant pressures P ═ 3MPa, 10MPa and 15MPa, respectively2The spectral distribution is shown in fig. 4(a, b, c). Comparison T2The spectral amplitude change is known, T after water flooding2The spectrum distribution presents a 'bimodal' state, which indicates that the rock core has strong heterogeneity.
When the displacement pressure Ca ≈ 2.71 × 10-6(P ═ 3MPa), the injected water preferentially enters the macropores, expressed as the relaxation time T2>The amplitude of 100ms is obviously reduced, and the water flooding dominant channel mainly follows the large holeThe throat direction is through. According to T2A cutoff value calculation method for finding a movable fluid T in a residual oil state2The cut-off was 86.975ms and the final displacement efficiency was 52.076%, indicating that a large amount of oil remained in the medium and small pore throats at this pressure.
When the displacement pressure P is 10MPa, T2>The 100ms large hole portion curve substantially coincides with the saturated oil condition, indicating that under this pressure condition, the oil in the large hole can be rapidly displaced to a residual oil condition. At the same time, T2<The curve of the medium and small pores with the length of 100ms obviously deviates to the left compared with that of Ca & lt 2.71X 10-6(P & lt 3MPa), and the descending range of the curve is obvious, which shows that when Ca & lt 1.24X 10-5 & gt, oil in the large pores is rapidly expelled out, and the dominant channel is gradually formed in the throats of the medium and small pores along with the gradual enhancement of the viscous force. Under the control of the capillary number, the movable fluid T is in the state of residual oil2The cut-off value was 75.646ms, indicating that water had entered the medium and small pores and displaced the oil from the space with a displacement efficiency of 55.057%.
When the capillary number is further increased to Ca ≈ 0.74 × 10-4(P ═ 15MPa), the oil in the large pore throat is further expelled, the residual oil amplitude in the small and medium pore throats is further reduced, and the mobile fluid T in the state of residual oil is at this time2The cut-off value was 65.793ms, and the displacement efficiency was 62.732%.
From the water flooding process of sample J305-3, it can be seen that: along with the increase of the number of capillaries, the displacement efficiency is gradually increased, and the movable fluid T in the state of residual oil2Decreasing cut-off value, nuclear magnetic T2The curve is shifted to the left, which shows that the number of capillaries has an important influence on the water flooding dominant channel and makes the capillary gradually transit from flowing mainly along the large pore throat to flowing along the medium and small pore throats.
In summary, the control effect of the capillary number on the water flooding dominant channel can be understood as follows: under the condition of low capillary number, the interfacial tension occupies the main position in the oil-water displacement process, water overcomes the capillary resistance and enters pores, oil is discharged in the form of small liquid drops, and the liquid drops gradually form a spherical shape in the transmission process to reduce the surface area of the liquid drops; when the number of capillaries is large, the viscous force plays a major role, and the fluid droplets are easily deformed during the transport due to the viscous force, and the droplets are stretched into an irregular shape and flow in the throat.
The verification result shows that:
(1) ca with different orders of magnitude has control effect on the fluid dominant channel in the pore throat space of the compact oil reservoir. When Ca is low, the research result is consistent with the traditional critical path analysis method. When Ca is present>10-5During the process, along with the enhancement of the viscous force action, the fluid dominant channel is controlled by the small throat with higher viscous force pressure drop, and the dominant channel formed by water flooding gradually moves towards the direction along which the viscous force is reduced.
(2) Along with the increase of the number of capillaries, the displacement efficiency is increased by 10.6 to 19.5 percent, and T2The cut-off value is continuously reduced, the oil in the middle and small pore throats is continuously driven out, and the average thickness of a residual oil liquid film is reduced by 5.946 mu m to 9.585 mu m.
(3) At low capillary numbers, the invader fluid enters the pore throat, mainly overcoming the capillary resistance, displacing the oil in the pores. As the number of capillaries increases, the viscous force dominates, the displacement rate in the small pores is much greater than that of the large pores, and therefore the invaded fluid enters the small pores and forms a dominant path.
(4) Along with the increase of the number of the capillaries, the saturation of residual oil in the pore throat space within the range of 10-100 ms is reduced to the maximum extent, and the volume of the fluid displaced from the corresponding medium-small pore throat is larger than that of the fluid displaced from the large-pore throat space within the range of more than 100ms, so that the control and influence of the number of the capillaries on the formation of the dominant channel in different scale spaces are further verified.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.
Claims (10)
1. An apparatus for testing fluid displacement efficiency over a range of different pore throat sizes, the apparatus comprising a fluid displacement system, a fluid measurement system, a flow metering system and a pressure line (2) for connection; the fluid displacement system comprises a high-pressure injection pump (11) and a middle water container (10) for storing heavy water, the fluid measuring system comprises a rock core holder (4), a nuclear magnetic resonance analyzer (1) and a manual confining pressure pump (8), the rock core holder (4) is connected with the nuclear magnetic resonance analyzer (1) through a pressure pipeline (2), and the fluid measuring system is composed of a transparent glass tube (3) and a measuring cylinder (5).
2. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: one end of the intermediate water container (10) is connected with the high-pressure injection pump (11), and the other end of the intermediate water container is connected with a communicating thread (14) at the side end of the rock core holder (4).
3. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: the core holder (4) comprises a hollow rubber barrel with metal kettle covers (16) at two ends, a rubber ring (12) is further arranged in the core holder, fluid can only flow to the end face along a throat and cannot seep to the side surface of a rock sample, the rock sample can be completely sealed after the rubber ring is heated, a metal shell (13) is arranged on the outer surface of the core holder, the metal shell is fixedly connected with a fixed supporting device (15), the position of the core holder is kept fixed by the fixed supporting device, and the core holder is prevented from shaking.
4. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: the other end of the rock core holder is connected with a manual confining pressure pump (8) which is used for applying constant pressure to the two ends of the rock core.
5. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: a uniflow valve (6) and a pressure gauge (7) are also arranged between the intermediate water container and the core holder; the uniflow valve is used for controlling the flow and the speed of fluid, and the pressure gauge is used for acquiring the pressure conditions of two ends of the rock core and water flooding.
6. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: the measuring cylinder (5) is used for directly reading the discharged oil quantity, and the scale value of the measuring cylinder (5) is accurate to 1 ml.
7. The apparatus for testing fluid displacement efficiency over a range of different pore throat sizes of claim 1, wherein: the pressure pipeline (2) is made of stainless steel materials, so that the pressure pipeline is prevented from being corroded by circulating liquid.
8. A method of testing fluid displacement efficiency over a range of different pore throat sizes according to the device of any one of claims 1 to 7, wherein: the method comprises the following steps:
s1, placing the saturated oil sample into a core holder;
s2, applying constant confining pressure to the core holder by using a manual confining pressure pump; and nuclear magnetic resonance T under the confining pressure2The spectral curve is used as reference, and the pore distribution range of the sample can be obtained quantitatively;
s3, injecting heavy water 17 into the core through the intermediate water container 10 by using the high-pressure injection pump 11 under constant pressure, and driving the white oil out of the core;
s4, quantitatively measuring accumulated oil production and water production through a metering system connected to the lower end of the core holder, increasing the displacement of reservoir oil along with the increase of injection time, stopping injecting heavy water until the oil mass on the outlet side is not increased any more, storing related experimental data, and acquiring the nuclear magnetic resonance T of water displacement under different capillary numerical control through a nuclear magnetic resonance analyzer2And mapping to obtain the displacement efficiency.
9. The method of claim 8, wherein: the preparation of the saturated oil sample in the step S1 is specifically as follows: cleaning and drying the sample to remove residual formation water, hydrocarbon fluid and salt, then aging the sample to keep the original wettability of the core, then applying vacuum to the sample, and saturating the sample with white oil under constant pressure until the sample is completely saturated to obtain a saturated oil sample.
10. The method of claim 9, wherein: the sample was saturated with white oil at constant pressure for 48h, the viscosity of which was 5mpa · s.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113884531A (en) * | 2021-09-29 | 2022-01-04 | 西南石油大学 | Imaging device and method for researching different section sequences of rock core based on nuclear magnetic resonance |
| CN114798029A (en) * | 2022-06-24 | 2022-07-29 | 中国石油大学(华东) | Microfluidic chip for testing stability of two-phase interface of pore throat structure and preparation method thereof |
| CN116603583A (en) * | 2023-07-20 | 2023-08-18 | 中国科学院地质与地球物理研究所 | Electric heating method and nuclear magnetic resonance online displacement system |
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2021
- 2021-06-11 CN CN202110655061.1A patent/CN113358542A/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| TING ZHAO: "Control of Generalized Capillary Number on Immiscible Displacement Path_ NMR Online and Network Simulation of Fluid Displacement Mechanism", 《ENERGY FUELS》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113884531A (en) * | 2021-09-29 | 2022-01-04 | 西南石油大学 | Imaging device and method for researching different section sequences of rock core based on nuclear magnetic resonance |
| CN114798029A (en) * | 2022-06-24 | 2022-07-29 | 中国石油大学(华东) | Microfluidic chip for testing stability of two-phase interface of pore throat structure and preparation method thereof |
| CN116603583A (en) * | 2023-07-20 | 2023-08-18 | 中国科学院地质与地球物理研究所 | Electric heating method and nuclear magnetic resonance online displacement system |
| CN116603583B (en) * | 2023-07-20 | 2023-09-15 | 中国科学院地质与地球物理研究所 | Electric heating method and nuclear magnetic resonance online displacement system |
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