CN107727527B - System for determining critical pressure gradient generated by foam at permeability mutation position - Google Patents
System for determining critical pressure gradient generated by foam at permeability mutation position Download PDFInfo
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- CN107727527B CN107727527B CN201710780568.3A CN201710780568A CN107727527B CN 107727527 B CN107727527 B CN 107727527B CN 201710780568 A CN201710780568 A CN 201710780568A CN 107727527 B CN107727527 B CN 107727527B
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- 239000006260 foam Substances 0.000 title claims abstract description 80
- 230000035699 permeability Effects 0.000 title claims abstract description 57
- 230000035772 mutation Effects 0.000 title claims abstract description 21
- 239000004576 sand Substances 0.000 claims abstract description 139
- 239000011521 glass Substances 0.000 claims abstract description 41
- 239000011324 bead Substances 0.000 claims abstract description 38
- 238000002347 injection Methods 0.000 claims abstract description 31
- 239000007924 injection Substances 0.000 claims abstract description 31
- 239000002245 particle Substances 0.000 claims abstract description 14
- 239000005341 toughened glass Substances 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims description 31
- 230000008859 change Effects 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 16
- 238000005187 foaming Methods 0.000 claims description 13
- 238000012360 testing method Methods 0.000 claims description 10
- 230000001965 increasing effect Effects 0.000 claims description 7
- 238000007789 sealing Methods 0.000 claims description 6
- 239000011148 porous material Substances 0.000 claims description 5
- 239000000243 solution Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
- 238000009825 accumulation Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims description 3
- 239000004711 α-olefin Substances 0.000 claims description 3
- 230000037050 permeability transition Effects 0.000 claims 2
- 238000011160 research Methods 0.000 abstract description 4
- 230000006872 improvement Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000004088 foaming agent Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000007619 statistical method Methods 0.000 description 2
- 239000004604 Blowing Agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000005465 channeling Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
- G01N7/10—Analysing materials by measuring the pressure or volume of a gas or vapour by allowing diffusion of components through a porous wall and measuring a pressure or volume difference
-
- 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
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- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
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- Dispersion Chemistry (AREA)
- Fluid Mechanics (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention belongs to the field of oil reservoir air-flooding exploitation, and particularly relates to a system for measuring a critical pressure gradient generated by foam at a permeability mutation position. The sand filling pipe is provided with an injection end and an outflow end, two sections of filling media with different particle sizes are arranged in the sand filling pipe, the filling media with smaller particle sizes are filled close to the injection end to form a front sand filling section, the filling media with larger particle sizes are filled close to the outflow end to form a rear sand filling section, the sand filling pipe is a transparent toughened glass pipe, the filling media are black glass beads, the sand filling pipe further comprises an observation device, the observation device comprises a microscope right facing the outer circumferential surface of the sand filling pipe and a computer connected with the microscope, and the microscope is provided with a camera. The system can measure the critical pressure gradient of the foam at the position of the permeability mutation, and the foam is placed in a porous medium environment for research so as to truly reflect the influence of the permeability mutation in the heterogeneous oil reservoir on the foam generation.
Description
Technical Field
The invention belongs to the field of oil reservoir air-flooding exploitation, and particularly relates to a system for measuring a critical pressure gradient generated by foam at a permeability mutation position.
Background
The foam fluid has higher apparent viscosity and better plugging performance, can be used as a plugging agent, improves swept volume and water injection profile, and can also be used as an oil displacement agent to improve the oil displacement efficiency of a heterogeneous oil layer. In actual mines, gas and a foaming agent system are generally injected into the formation at the same time, and the gas and the foaming agent system are mixed in the formation to form foam, so that the foam can play a role. The foam presents a minimal pressure gradient in the porous medium, i.e., a critical pressure gradient. When the formation pressure gradient is smaller than the critical pressure gradient, weak foam which has larger bubble size, is looser and has high gas flow rate is generated; when the formation pressure gradient is larger than the critical pressure gradient, strong foam with smaller bubble size, large liquid film number density and lower gas fluidity is generated. The weak foam has poor plugging capability on pores, and the strong foam has strong plugging capability. The presence of a critical pressure gradient is detrimental to enhanced oil recovery applications using foam flooding, and the magnitude of the critical pressure gradient affecting foam generation is closely related to the velocity of the injected gas and liquid phases, the pore shape of the porous media, the oil saturation, the type and concentration of the surfactant, and the like.
The sudden increase in permeability facilitates the formation of foam as the blowing agent solution and gas permeate from the hypotonic layer to the hypertonic layer. In the current indoor experiment, a foaming device is mainly adopted to inject foamed foam serving as a displacing agent into a porous medium, and then the resistance coefficient of the foam is researched; or to study the effect of different factors on the properties of the resulting foam. These studies are premised on that foam has been generated, and do not consider the effect of very poor permeability at the boundaries of sudden permeability increases on foam generation. In addition, the existing observation on the form of the generated foam generally comprises the steps of sampling and then moving to a microscope for observation, or connecting a hollow sampler at the outlet end of a core, wherein the foam is separated from the porous medium environment, so that the influence on the foam generation when the permeability of the actual heterogeneous oil reservoir is mutated cannot be truly reflected.
Disclosure of Invention
Aiming at the problem that the influence of the permeability mutation on the foam generation is not considered by the existing laboratory foam flooding experiential prescription, the invention aims to provide a system for measuring the critical pressure gradient of the foam generation at the permeability mutation position, the influence of the permeability mutation on the foam generation is considered, the critical pressure gradient of the foam generation at the permeability mutation position can be measured, and the foam is placed in a porous medium environment for research so as to truly reflect the influence of the permeability mutation on the foam generation in the heterogeneous oil reservoir.
It is another object of the present invention to provide a method for determining the critical pressure gradient for foam generation at a permeability discontinuity using the above system.
The invention provides the following technical scheme:
a system for measuring a critical pressure gradient generated by foam at a permeability mutation position comprises a sand filling pipe, a liquid supply device, a gas supply device and a data acquisition device connected with the sand filling pipe, wherein the sand filling pipe is provided with an injection end and an outflow end, two sections of filling media with different particle sizes are arranged in the sand filling pipe, the filling media with smaller particle sizes are filled close to the injection end to form a front sand filling section, the filling media with larger particle sizes are filled close to the outflow end to form a rear sand filling section, the front sand filling section is connected with the rear sand filling section, and the liquid supply device and the gas supply device are respectively communicated with the injection end through a constant pressure pump.
The system comprises a sand filling pipe, a liquid supply device, a gas supply device and a data acquisition device, wherein the liquid supply device and the gas supply device provide foaming liquid and gas to be mixed in the filling pipe to form foam, a front sand filling section and a rear sand filling section which are arranged in the sand filling pipe form two heterogeneous medium filling sections with different permeabilities, and the permeability of the front sand filling section is smaller than that of the rear sand filling section due to the small diameter of the front sand filling section and the large diameter of the rear sand filling section, so that the foam is more easily formed due to the sudden change of the permeability in the process that the foaming liquid and the gas flow from the front sand filling section to the rear sand filling section. The data acquisition device acquires the pressure change in the sand filling pipe so as to calculate the critical pressure gradient generated by the foam, fully considers the influence of the permeability range at the boundary with suddenly increased permeability on the generation of the foam, and improves the calculation precision of the critical pressure gradient.
As an improvement of the invention, the sand filling pipe is a transparent toughened glass pipe, and the filling medium is black glass beads. The generation state of foam in the sand filling pipe can be observed through arranging the transparent toughened glass pipe, and the contrast effect is strengthened through the black glass beads.
As an improvement of the invention, the ports of the injection end and the outflow end are provided with screens, and the aperture of each screen is smaller than the particle size of the filling medium. Enhancing the stability of the filling medium.
As an improvement of the sand filling device, the length ratio of the front sand filling section to the rear sand filling section is 1: 1-2: 1. Ensuring that the fluid fully flows in the front sand-filling section.
As an improvement of the invention, the data acquisition device comprises a plurality of pressure sensors, a pressure data acquisition unit connected with the pressure sensors and a computer connected with the pressure data acquisition unit, wherein the sand-filled pipe is provided with a sealing hole, the pressure sensors penetrate through the sealing hole and extend into the sand-filled pipe, and the pressure sensors are uniformly distributed along the length direction of the sand-filled pipe. The pressure loss at each section of the sand pack pipe can be measured, and the position where the pressure loss mainly occurs can be judged.
As an improvement of the invention, two sides of the boundary of two sections of filling media of the sand filling pipe are respectively provided with a pressure sensor. And detecting the pressure change at the two sides of the permeability mutation position, and judging whether foam is generated or not.
As an improvement of the method, the sand filling pipe sand filling device further comprises an observation device, wherein the observation device comprises a microscope facing the outer circumferential surface of the sand filling pipe and a computer connected with the microscope, and the microscope is provided with a camera. The form and migration rule of the foam, particularly the form change of the foam before and after the permeability mutation, are clearly observed, and the parameters capable of reflecting the performance of the foam are obtained through the statistical analysis of the foam.
A method of determining a critical pressure gradient for foam generation at a permeability discontinuity, comprising the steps of:
(1) and (3) determination of medium permeability: selecting a transparent toughened glass tube as a sand filling tube, filling black glass beads with small diameters in the sand filling tube, vacuumizing the sand filling tube, then adding water to saturate pores in the sand filling tube, heating the sand filling tube to a target oil reservoir temperature to measure permeability, replacing the black glass beads with large diameters to fill the sand filling tube, and measuring the permeability;
(2) assembling a system: filling black glass beads with small diameter in the step (1) into one side of an injection end of a sand filling pipe to form a front sand filling section, filling black glass beads with large diameter to form a rear sand filling section, communicating the injection end of the sand filling pipe with a liquid supply device and a gas supply device through a constant pressure pump, connecting an outflow end of the sand filling pipe with a liquid accumulation barrel, connecting a data acquisition device and an observation device with the sand filling pipe to obtain a system for measuring the critical pressure gradient generated by foam at a permeability mutation position, and testing the air tightness of the system;
(3) injecting foaming liquid: injecting 0.4wt% of alpha-olefin sulfonate solution serving as foaming liquid into the sand filling pipe, wherein the injection number is 8-10 PV;
(4) drawing a relation graph: keeping the inflow velocity of foaming liquid injection unchanged, injecting gas through a gas supply device, collecting pressure values of all parts in the sand filling pipe after the pressure of the sand filling pipe is stable, recording the form change of foam, gradually increasing the pressure of the gas until the gas flow velocity is reduced by 10 times, and drawing a relation curve graph of the pressure gradient along with the change of the gas flow velocity, wherein the pressure gradient is the ratio of the pressure difference of any front part and any back part on the sand filling pipe to the length of the sand filling pipe;
(5) obtaining a critical pressure gradient: and (4) finding an inflection point appearing on the relation curve chart obtained in the step (4), and if the foam density at the boundary of the corresponding front sand-packed section and the corresponding rear sand-packed section is increased, the pressure gradient value corresponding to the inflection point is the critical pressure gradient.
Two kinds of black glass beads with different meshes are filled in a transparent toughened glass tube, the black glass beads with smaller meshes are filled in the front half part to form a porous medium with lower permeability, and the black glass beads with larger meshes are filled in the rear half part to form a porous medium with higher permeability. The method comprises the following steps of uniformly distributing a plurality of pressure measuring points on the whole glass tube, wherein one pressure measuring point is distributed on each boundary with abrupt change of permeability, namely two sides of the high-permeability and low-permeability connecting end surfaces, injecting gas and foaming agent solution from the low-permeability end, detecting pressure change of each pressure measuring point, and obtaining the position where foam is generated as the part where displacement pressure difference is abrupt change. The foam is placed in a porous medium environment for research, whether the foam is generated and the form of the foam are observed in real time through the outer wall of the toughened glass tube and an observation device, the shot image is subjected to statistical analysis to obtain parameters capable of reflecting the performance of the foam, the influence of the sudden change of the permeability in the heterogeneous oil reservoir on the foam generation is truly reflected, and finally the influence of the critical pressure gradient and the extremely poor permeability on the foam generation limit is obtained according to the pressure difference change and the performance parameters of the foam.
As an improvement of the method of the invention, the black glass beads in the step (1) are firstly bonded on the inner wall surface of the sand filling pipe through epoxy resin to form a glass bead layer, and then the residual black glass beads are filled. Preventing the injected foaming liquid and gas from channeling on the wall surface of the toughened glass tube.
As an improvement of the method, the method for testing the air tightness of the system is to place the system under the pressure of 2MPa to test the pressure for 30min without air leakage. Ensuring good air tightness of the system.
The invention has the following beneficial effects:
the system can measure the critical pressure gradient generated by the foam at the position of the permeability mutation, and the foam is placed in a porous medium environment for research so as to truly reflect the influence of the permeability mutation in the heterogeneous oil reservoir on the foam generation.
Drawings
FIG. 1 is a block diagram of the system of the present invention.
FIG. 2 is a graph of pressure gradient versus gas flow rate for experimental group 1 of the method of the invention.
FIG. 3 is a graph showing the foam morphology at a pressure gradient of 0.030MPa/m in test group 1 according to the method of the present invention.
FIG. 4 is a graph showing the foam morphology at a pressure gradient of 0.078MPa/m in test group 1 of the process of the present invention.
FIG. 5 is a graph of pressure gradient versus gas flow rate for experimental group 2 of the method of the invention.
In the figure: 1. the device comprises a sand filling pipe 11, a front sand filling section 12, a rear sand filling section 2, a liquid supply device 3, a gas supply device 31, a gas flowmeter 32, a one-way valve 4, a data acquisition device 41, a pressure sensor 42, a pressure acquisition device 43, a computer 5, an observation device 51, a microscope 6, a constant pressure pump 7 and a liquid accumulating cylinder.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings.
As shown in the attached figure 1, the system for measuring the critical pressure gradient generated by the foam at the abrupt change of the permeability comprises a sand filling pipe 1, a liquid supply device 2, a gas supply device 3, a data acquisition device 4 and an observation device 5, wherein the data acquisition device 4 and the observation device 5 are connected with the sand filling pipe, the sand filling pipe is provided with an injection end and an outflow end, two sections of filling media with different particle sizes are arranged in the sand filling pipe, the filling media with smaller particle sizes are filled close to the injection end to form a front sand filling section 11, the filling media with larger particle sizes are filled close to the outflow end to form a rear sand filling section 12, the front sand filling section is connected with the rear sand filling section, the length ratio of the front sand filling section to the rear sand filling section is 1: 1-2: 1, preferably 2:1, the liquid supply device and the gas supply device are respectively communicated with the injection end through a constant pressure pump 6, a gas flowmeter 31 is arranged on a pipeline between the gas, the outflow end is communicated with the effusion barrel 7.
The sand filling pipe is a transparent toughened glass pipe, the inner diameter of the glass pipe is 2-5 cm, the length of the glass pipe is 30-60 cm, the filling medium is black glass beads, the ports of the injection end and the outflow end are provided with screens, the data acquisition device comprises a plurality of pressure sensors 41, a pressure data acquisition unit 42 connected with the pressure sensors and a computer 43 connected with the pressure data acquisition unit, the sand filling pipe is provided with sealing holes, the pressure sensors penetrate through the sealing holes and extend into the sand filling pipe, the pressure sensors are uniformly distributed along the length direction of the sand filling pipe, the precision of the pressure sensors is 0.001MPa, preferably 5 pressure sensors are arranged, the sand filling pipe comprises two pressure sensors arranged on two sides of a boundary of two sections of the filling medium of the sand filling pipe, one pressure sensor is arranged on each of a port of the injection end and a port of the outflow end of the sand filling pipe, the observation device comprises a microscope 51, a microscope, a, The computer is connected with the microscope, the microscope is provided with a camera, the model of the microscope is MBL2000, the optical resolution is 480 times, and the camera is a CCD camera with seven million pixels.
A method of determining a critical pressure gradient for foam generation at a permeability discontinuity, comprising the steps of:
(1) and (3) determination of medium permeability: selecting a transparent toughened glass tube as a sand filling tube, filling black glass beads with small diameters in the sand filling tube, vacuumizing the sand filling tube, adding water to saturate pores in the sand filling tube, wherein the injection number of the water is 1 PV, heating the sand filling tube to a target oil reservoir temperature to measure the permeability, replacing the black glass beads with large diameters to fill the sand filling tube and measure the permeability, bonding the black glass beads on the inner wall surface of the sand filling tube by using epoxy resin to form a glass bead layer when filling the black glass beads, and then continuously filling the rest black glass beads;
(2) assembling a system: filling black glass beads with small diameter in the step (1) into one side of an injection end of a sand filling pipe to form a front sand filling section, then filling black glass beads with large diameter to form a rear sand filling section, communicating the injection end of the sand filling pipe with a liquid supply device and a gas supply device through a constant pressure pump, connecting an outflow end of the sand filling pipe with a liquid accumulation barrel, and connecting a data acquisition device and an observation device with the sand filling pipe to obtain a system for measuring the critical pressure gradient generated by foam at a permeability mutation position, and testing the air tightness of the system by placing the system under the pressure of 2MPa to test the pressure for 30min to ensure that the system is airtight;
(3) injecting foaming liquid: injecting 0.4wt% of alpha-olefin sulfonate solution serving as foaming liquid into the sand filling pipe, wherein the injection number is 8-10 PV;
(4) drawing a relation graph: keeping the inflow velocity of foaming liquid unchanged, injecting gas through a gas supply device, collecting pressure values of all parts in a sand filling pipe after the pressure of the sand filling pipe is stable, recording the form change of foam, gradually increasing the pressure of the gas until the gas flow velocity is reduced by 10 times, and drawing a relation curve graph of the pressure gradient along with the change of the gas flow velocity, wherein the pressure gradient is the ratio of the pressure difference of any front part and any rear part on the sand filling pipe to the length of the sand filling pipe, and preferably the ratio of the pressure difference between an injection end and an outflow end of the sand filling pipe to the length of the sand filling pipe;
(5) obtaining a critical pressure gradient: and (4) finding an inflection point appearing on the relation curve chart obtained in the step (4), wherein the foam density at the boundary of the front sand-packed section and the rear sand-packed section at the moment of the inflection point is increased, and the pressure gradient value corresponding to the inflection point is the critical pressure gradient.
Test data
Experimental group 1: the diameter of the black glass beads in the front sand filling section is 0.15mm, the permeability is 1.2D, the diameter of the black glass beads in the rear sand filling section is 0.42mm, the permeability is 6.1D, the permeability range of the front sand filling section and the rear sand filling section is 5.08, the liquid injection speed is 0.7m/D, the obtained pressure gradient and the gas flow rate are plotted to obtain a graph 2, the critical pressure gradient is 0.072MPa/m, namely the value of the longitudinal coordinate corresponding to the point A in the graph 2, wherein the foam form obtained when the pressure gradient is 0.030MPa/m is shown in a graph 3, and the foam form obtained when the pressure gradient is 0.078MPa/m is shown in a graph 4. As can be seen from comparison between fig. 3 and 4, when the pressure gradient is smaller than the critical pressure gradient, the foam is loose and has a larger size, and when the pressure gradient is larger than the critical pressure gradient, the foam is dense and has a smaller size.
Experimental group 2: the diameter of the black glass beads in the front sand filling section is 0.084mm, the permeability is 0.5D, the diameter of the black glass beads in the rear sand filling section is 0.59mm, the permeability is 8.6D, the permeability range of the front sand filling section and the rear sand filling section is 17.2, the liquid injection speed is 0.7m/D, the obtained relation curve of the pressure gradient and the gas flow rate is shown in figure 5, and the critical pressure gradient is 0.020MPa/m, namely the value of the vertical coordinate corresponding to the point B in figure 5.
Claims (8)
1. A system for measuring a critical pressure gradient generated by foam at a permeability mutation position is characterized by comprising a sand filling pipe, a liquid supply device, a gas supply device and a data acquisition device connected with the sand filling pipe, wherein the sand filling pipe is provided with an injection end and an outflow end, two sections of filling media with different particle sizes are arranged in the sand filling pipe, the filling media with smaller particle sizes are filled close to the injection end to form a front sand filling section, the filling media with larger particle sizes are filled close to the outflow end to form a rear sand filling section, the front sand filling section is connected with the rear sand filling section, so that the permeability of the front sand filling section is smaller than that of the rear sand filling section, and the liquid supply device and the gas supply device are respectively communicated with the injection end through a constant pressure pump; the filling medium is glass beads;
the glass beads are bonded on the inner wall surface of the sand filling pipe through epoxy resin to form a glass bead layer, and then the residual glass beads are filled;
the length ratio of the front sand filling section to the rear sand filling section is 1: 1-2: 1;
the data acquisition device comprises a plurality of pressure sensors, and two sides of a boundary of two sections of filling media of the sand filling pipe are respectively provided with one pressure sensor.
2. The system for determining the critical pressure gradient for foam generation at a permeability transition as claimed in claim 1, wherein the sand-filled pipe is a transparent tempered glass pipe and the filling medium is black glass beads.
3. The system for determining the critical pressure gradient of foam generation at a permeability jump as claimed in claim 1 or 2, wherein a screen is provided at the port of the injection end and the outflow end, and the aperture of the screen is smaller than the particle size of the filling medium.
4. The system for determining the critical pressure gradient of foam generation at a permeability mutation as claimed in claim 1, wherein the data acquisition device further comprises a pressure data acquisition unit connected with the pressure sensor and a computer connected with the pressure data acquisition unit, the sand-packed pipe is provided with a sealing hole, the pressure sensor passes through the sealing hole and extends into the sand-packed pipe, and the pressure sensor is uniformly distributed along the length direction of the sand-packed pipe.
5. The system for determining the critical pressure gradient for foam generation at a permeability transition as claimed in claim 2, further comprising an observation device, wherein the observation device comprises a microscope facing the outer circumferential surface of the sand pack pipe, and a computer connected with the microscope, and the microscope is provided with a camera.
6. A method for determining the critical pressure gradient for foam generation at a permeability discontinuity using the system of claim 5, comprising the steps of:
(1) and (3) determination of medium permeability: selecting a transparent toughened glass tube as a sand filling tube, filling black glass beads with small diameters in the sand filling tube, vacuumizing the sand filling tube, then adding water to saturate pores in the sand filling tube, heating the sand filling tube to a target oil reservoir temperature to measure permeability, replacing the black glass beads with large diameters to fill the sand filling tube, and measuring the permeability;
(2) assembling a system: filling black glass beads with small diameter in the step (1) on one side of an injection end of a sand filling pipe to form a front sand filling section, then filling black glass beads with large diameter in the step (1) to form a rear sand filling section, communicating the injection end of the sand filling pipe with a liquid supply device and a gas supply device through a constant pressure pump, connecting an outflow end of the sand filling pipe with a liquid accumulation cylinder, connecting a data acquisition device and an observation device with the sand filling pipe to obtain a system for measuring the critical pressure gradient generated by foam at a permeability mutation position, and testing the air tightness of the system;
(3) injecting foaming liquid: injecting 0.4wt% of alpha-olefin sulfonate solution serving as foaming liquid into the sand filling pipe, wherein the injection number is 8-10 PV;
(4) drawing a relation graph: keeping the inflow velocity of foaming liquid injection unchanged, injecting gas through a gas supply device, collecting pressure values of all parts in the sand filling pipe after the pressure of the sand filling pipe is stable, recording the form change of foam, gradually increasing the pressure of the gas until the gas flow velocity is reduced by 10 times, and drawing a relation curve graph of the pressure gradient along with the change of the gas flow velocity, wherein the pressure gradient is the ratio of the pressure difference of any front part and any back part on the sand filling pipe to the length of the sand filling pipe;
(5) obtaining a critical pressure gradient: and (4) finding an inflection point appearing on the relation curve chart obtained in the step (4), and if the foam density at the boundary of the corresponding front sand-packed section and the corresponding rear sand-packed section is increased, the pressure gradient value corresponding to the inflection point is the critical pressure gradient.
7. The method according to claim 6, wherein the black glass beads in step (1) are bonded to the inner wall surface of the sand-filled pipe by epoxy resin to form a glass bead layer, and then the remaining glass beads are filled.
8. The method of claim 6, wherein the airtightness of the system is tested by placing the system under a pressure of 2MPa and testing the pressure for 30 min.
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| CN109594960A (en) * | 2019-01-07 | 2019-04-09 | 中国海洋石油集团有限公司 | The visual experimental apparatus and its visualization sandpack column of analog composite foam profile control |
| CN109856326A (en) * | 2019-01-11 | 2019-06-07 | 成都理工大学 | A kind of novel foam evaluating apparatus and method |
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| CN111185478A (en) * | 2020-03-13 | 2020-05-22 | 昆明理工大学 | Method for restoring cadmium-polluted soil based on switch surfactant |
| CN112782045B (en) * | 2021-02-05 | 2022-04-12 | 西南石油大学 | Device for measuring permeability of high-temperature and high-pressure foam liquid film and using method thereof |
| CN114278258B (en) * | 2021-09-24 | 2023-07-18 | 中国海洋石油集团有限公司 | Length-adjustable temperature-resistant visual sand filling pipe |
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| CN102288517A (en) * | 2010-06-21 | 2011-12-21 | 中国石油天然气股份有限公司 | Method for evaluating foam property |
| CN204374167U (en) * | 2014-12-04 | 2015-06-03 | 中国石油天然气股份有限公司 | A kind of foaming properties evaluation system |
| CN204903506U (en) * | 2015-09-02 | 2015-12-23 | 中国石油集团渤海钻探工程有限公司 | Foam flooding evaluation device |
| CN105842127B (en) * | 2016-05-31 | 2019-01-11 | 上海大学 | For studying the experimental provision of displacement of reservoir oil liquid foams drainage migration process form |
| CN106526084B (en) * | 2016-11-11 | 2018-09-07 | 中国石油天然气股份有限公司 | A kind of recover the oil uses foaming properties measurement device and method |
| CN106814011A (en) * | 2016-12-26 | 2017-06-09 | 浙江海洋大学 | It is a kind of to determine the device and method that foam generates boundary in porous media |
| CN107064434B (en) * | 2017-05-25 | 2020-01-03 | 浙江海洋大学 | Device for measuring effective migration distance of air foam between wells |
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2017
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