CN117725445B - Sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity - Google Patents
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 272
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 139
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 139
- 238000004364 calculation method Methods 0.000 title claims abstract description 50
- 239000011435 rock Substances 0.000 claims abstract description 41
- 239000012530 fluid Substances 0.000 claims abstract description 40
- 238000005342 ion exchange Methods 0.000 claims abstract description 16
- 238000004090 dissolution Methods 0.000 claims abstract description 13
- 230000003321 amplification Effects 0.000 claims abstract description 9
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 188
- 239000011148 porous material Substances 0.000 claims description 114
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 94
- 239000012071 phase Substances 0.000 claims description 68
- 229920006395 saturated elastomer Polymers 0.000 claims description 53
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 40
- 210000004027 cell Anatomy 0.000 claims description 34
- 239000011780 sodium chloride Substances 0.000 claims description 20
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 claims description 18
- 239000008346 aqueous phase Substances 0.000 claims description 14
- 238000005315 distribution function Methods 0.000 claims description 6
- 238000002474 experimental method Methods 0.000 claims description 4
- 150000002500 ions Chemical class 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 150000001450 anions Chemical class 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 150000001768 cations Chemical class 0.000 claims description 3
- 210000005056 cell body Anatomy 0.000 claims description 3
- 229910001415 sodium ion Inorganic materials 0.000 claims description 3
- 238000006467 substitution reaction Methods 0.000 claims description 3
- 238000011161 development Methods 0.000 abstract description 3
- 238000012544 monitoring process Methods 0.000 abstract description 3
- 238000009736 wetting Methods 0.000 abstract description 3
- 238000012512 characterization method Methods 0.000 abstract description 2
- 230000009919 sequestration Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000033558 biomineral tissue development Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000008398 formation water Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
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Abstract
The invention discloses a sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity, and relates to the technical field of oil and gas field exploration and development. According to the invention, a complex-structure porous medium model is established according to the real internal structure of rock, after the porous medium is characterized based on a fractal theory, a rectangular capillary bundle model is established in the complex-structure porous medium model, the cross section shape and the wall roughness of the capillary bundle model are set, the amplification radiuses of different apertures Mao Guanshu in a representative unit body are characterized, the influence of wettability and miscible fluid on the capillary bundle is established, an electric conductivity model considering ion flow, wetting wall ion exchange and supercritical carbon dioxide dissolution is established, and the complex-structure porous medium model is utilized to invert to obtain the change condition of the saturation aperture of each phase fluid and the saturation of supercritical carbon dioxide. The invention realizes accurate characterization of complex porous medium structure and rock conductivity in the sandstone reservoir, and improves the monitoring precision of supercritical carbon dioxide saturation in the sandstone reservoir.
Description
Technical Field
The invention relates to the technical field of oil and gas field exploration and development, in particular to a sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity.
Background
Geological sequestration of supercritical carbon dioxide (scCO 2) is the injection of carbon dioxide captured in industry into deep rock, thereby permanently removing carbon dioxide from the atmosphere, and has become an important means to achieve sustainable development of global carbon neutralization. In recent years, supercritical carbon dioxide sequestration technology has become mature, and on-site sequestration experiments have been developed at multiple sites around the world with staged results. But there is increasing evidence that the safety of supercritical carbon dioxide geological sequestration is a major challenge limiting its large-scale application. Therefore, how to effectively prevent, monitor and control the leakage of supercritical carbon dioxide and ensure the safety of geological storage of supercritical carbon dioxide has become an important issue for those skilled in the art to pay attention to at present.
By adopting resistivity logging and fractal theory, the saturation change of formation water, supercritical carbon dioxide and miscible fluid in the supercritical carbon dioxide sealing process can be effectively calculated. However, since the sandstone reservoir has a complex porous medium structure, carbon dioxide is injected into the stratum to be in a supercritical state, and the conductivity of stratum water is changed due to the dissolution of supercritical carbon dioxide, the existing fractal calculation method greatly simplifies the sandstone pore structure, for example, ignoring factors such as the shape of the pore cross section, the pore-throat ratio, the roughness of the wall surface, the wettability of the wall surface, the diameter change of capillary bundles, the dissolution of scCO2 and the like, and cannot accurately represent the sandstone porous structure, so that the change of saturation degree during geological storage of the supercritical carbon dioxide cannot be accurately monitored, the error of the calculation result of the saturation degree of the supercritical carbon dioxide is larger, and the direct guiding significance is lacked.
The Chinese patent No. 114112841A discloses a calculation method of the irreducible water saturation of a tight sandstone reservoir, but the method assumes that the diameter of a single capillary bundle is unchanged, excessively simplifies the structure of a tight sandstone pore, ignores important factors such as the shape of a porous medium and the roughness of a wall surface, is only suitable for immiscible two-phase fluid, and cannot accurately calculate the saturation change of supercritical carbon dioxide in the sandstone pore.
Because the fractal theory adopted in the prior art cannot accurately represent the porous medium structure of sandstone, the rock conductivity change caused by supercritical carbon dioxide dissolution is ignored, and the accuracy requirement for monitoring the saturation change of the supercritical carbon dioxide sealed in the sandstone reservoir cannot be met. Therefore, it is highly desirable to propose a method for calculating the supercritical carbon dioxide saturation of a sandstone reservoir based on conductivity, so as to realize accurate calculation of the supercritical carbon dioxide saturation in the sandstone reservoir.
Disclosure of Invention
The invention aims to realize accurate calculation of the supercritical carbon dioxide saturation in a sandstone reservoir, provides a sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity, realizes accurate characterization of rock conductivity change caused by a sandstone reservoir complex porous medium structure and supercritical carbon dioxide dissolution, and improves the accuracy of monitoring the supercritical carbon dioxide sealing saturation in the sandstone reservoir.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the sandstone reservoir supercritical carbon dioxide saturation calculating method based on conductivity comprises the following steps:
step 1, constructing a porous medium model with a complex structure according to the real structure of the porous medium, and representing the porous medium in the porous medium model with the complex structure based on a fractal theory;
Step 2, constructing a rectangular capillary bundle model in the porous medium model with the complex structure, and setting the cross-sectional shape and the wall roughness of the capillary bundle model;
Step 3, selecting a substitution table unit body in the complex structure porous medium model, and representing the amplification radii of different apertures Mao Guanshu in the unit body;
step 4, constructing the influence of wettability and miscible fluid on different pore diameters Mao Guanshu;
Step 5, constructing a conductivity model considering ion flow, wetted wall ion exchange and supercritical carbon dioxide dissolution;
And 6, inverting by using a porous medium model with a complex structure to obtain the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid at different moments, and obtaining the change condition of the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid.
Preferably, in the step 1, a distribution rule of pore sizes in the porous medium is obtained based on a real structure of the porous medium, as shown in formula (1):
（1）
In the method, in the process of the invention, Is the total number of capillary bundles, and is dimensionless; /(I)The unit is mu m for the maximum capillary bundle radius in the sandstone porous medium; /(I)The unit is mu m for the capillary bundle radius in the sandstone porous medium; /(I)Fractal dimension of pore area, on two dimensionsDimensionless;
Deriving the formula (1) to obtain the relationship between the number of pores and the pore size in the pore radius range, as shown in the formula (2):
（2）
In the method, in the process of the invention, Mao Guanshu,/>, within an infinitely small rangeIs an aperture in an infinitely small range;
determining a total number of capillary bundles between a minimum capillary bundle radius and a maximum capillary bundle radius in a sandstone porous medium The method comprises the following steps:
（3）
In the method, in the process of the invention, Is the smallest Mao Guanshu radius in the sandstone porous medium, and the unit is mu m;
combining equation (2) and equation (3) to obtain a probability density distribution function, as shown in equation (4):
（4）
In the method, in the process of the invention, Is a probability density function and is dimensionless;
integrating probability density distribution function to determine the applicable condition of fractal theory to obtain Or/>When the fractal theory is adopted, the fractal theory formula is as follows:
（5）
wherein,
（6）
In the method, in the process of the invention,Is the porosity of the porous medium and is dimensionless.
Preferably, in the step 2, the micro conical structures are geometrically and uniformly distributed on the surface of the capillary bundle model, so as to characterize the rough surface of the capillary bundle wall surface, as shown in formula (7):
（7）
In the method, in the process of the invention, The average height of the mini cone is expressed in mu m; /(I)The height of the micro cone is expressed in mu m; /(I)Is the pore size length, in μm; /(I)The coarse porosity of the wall surface is dimensionless;
setting the true pore radius of the capillary bundle in the capillary bundle model, as shown in formula (8):
（8）
In the method, in the process of the invention, The unit is the minimum pore radius on the section of the unit in the real pore; /(I)The maximum pore radius is saturated by bound water in a real pore, and the unit is mu m; /(I)The maximum pore radius is saturated by water in real pores, and the unit is mu m; The maximum pore radius is saturated by the mixed phase of supercritical carbon dioxide and water in real pores, and the unit is mu m; /(I) The unit is the maximum pore radius on the section of the unit in the real pore; /(I)The true pore radius is expressed in mu m; /(I)The unit is mu m, which is the maximum pore radius of the mixed phase saturation of the supercritical carbon dioxide and water in the sandstone porous medium; /(I)The maximum pore radius of the binding water saturation in the sandstone porous medium is expressed in mu m.
Preferably, in the step 3, a surface unit body is selected and replaced in the porous medium model with a complex structure, and the enlarged radius of different apertures Mao Guanshu in the representative unit body is changed to represent the enlarged deformation condition of the capillary bundles inside sandstone;
selecting a representative unit body, and calculating the total length of the bends Mao Guanshu in the representative unit body, as shown in formula (9):
（9）
In the method, in the process of the invention, Fractal dimension, two-dimensional space/>, of geometric tortuosity of capillary bundlesDimensionless; /(I)The total length of the bend Mao Guanshu is expressed in mu m; /(I)Average pore radius in μm; /(I)To represent the total length of the unit cell, the units are μm;
The capillary bundle radii of different pore sizes were characterized as:
（10）
In the method, in the process of the invention, The maximum capillary bundle growth radius is the true pore, and the unit is mu m; /(I)The unit is mu m for the maximum capillary bundle growth radius; /(I)The maximum radius in μm representing the unit body of the largest pore Mao Guanshu among the true pores; /(I)The method is a capillary bundle radius change period and is dimensionless;
The volume of the single hair bundle is determined as follows:
（11）
In the method, in the process of the invention, The volume of the capillary bundle in the sandstone porous medium is expressed as mu m 3.
Preferably, in the step 4, classification is performed on capillary bundle saturated fluids with different apertures, and the wettability of the wall surface of the water-wet rock and the influence of supercritical carbon dioxide and water mixing on each aperture Mao Guanshu are represented;
Respectively determining the total pore volume of the representative unit body, the total volume of the restrained capillary tube bundle, the total volume of the water saturated capillary tube bundle, the total volume of the mixed phase saturated capillary tube bundle and the total volume of supercritical carbon dioxide saturation Mao Guanshu;
The calculation formula of the total pore volume of the representative unit body is as follows:
（12）
In the method, in the process of the invention, To represent the total pore volume of the unit cell, in μm 3;
The calculation formula of the total volume of the restrained water capillary bundles in the representative unit body is as follows:
（13）
In the method, in the process of the invention, The unit is mu m 3 for representing the total volume of the restrained capillary bundles inside the unit body;
The total volume calculation formula of the water saturated capillary bundles in the representative unit body is as follows:
（14）
In the method, in the process of the invention, To represent the total volume of water saturation Mao Guanshu inside the unit cell, the unit is μm 3;
the total volume calculation formula of the mixed phase saturated capillary bundles in the representative unit body is as follows:
（15）
In the method, in the process of the invention, To represent the total volume of miscible saturation Mao Guanshu inside the unit cell, the unit is μm 3;
the calculation formula of the total volume of the supercritical carbon dioxide saturation Mao Guanshu in the representative unit body is as follows:
（16）
In the method, in the process of the invention, To represent the total volume of supercritical carbon dioxide saturation Mao Guanshu inside the unit cell, the unit is μm 3.
Preferably, the irreducible water saturation, the aqueous phase saturation, the miscible fluid saturation and the supercritical carbon dioxide saturation of the proxy unit are determined based on the total pore volume of the proxy unit and the total volume of the irreducible water capillary bundle, the total volume of the water saturated capillary bundle, the total volume of the mixed phase saturated capillary bundle and the total volume of the supercritical carbon dioxide saturation Mao Guanshu inside the proxy unit;
the calculation formula of the irreducible water saturation of the representative unit body is as follows:
（17）
In the method, in the process of the invention, To represent the irreducible water saturation of the unit cell;
the water phase saturation calculation formula of the representative unit body is as follows:
（18）
In the method, in the process of the invention, Water phase saturation representing the unit cell;
the formula for calculating the saturation of the mixed phase fluid of the representative unit body is as follows:
（19）
In the method, in the process of the invention, To represent the miscible fluid saturation of the unit cell;
the calculation formula of the supercritical carbon dioxide saturation of the representative unit body is as follows:
（20）
In the method, in the process of the invention, Is representative of the supercritical carbon dioxide saturation of the unit cell.
Preferably, in the step 5, the resistivity of the water saturation Mao Guanshu in the conductivity model is:
（21）
In the method, in the process of the invention, The resistivity of water saturation Mao Guanshu is expressed as omega-m; /(I)Is a form factor in μm; /(I)Saturated capillary radius for aqueous phase in μm; /(I)Specific surface conductivity of the water phase wetted wall surface ion exchange is S; /(I)To represent the cross-sectional area of the cell body, the unit is μm 2;
the resistivity of the supercritical carbon dioxide and water miscible phase saturation Mao Guanshu is:
（22）
In the method, in the process of the invention, The specific resistance of the water-carbon dioxide/water mixed phase saturation Mao Guanshu is omega-m; /(I)For normalizing the conductivity coefficient, dimensionless; /(I)Specific surface conductivity of the mixed phase wall surface ion exchange is S; /(I)Is the radius of a mixed phase saturated capillary, and the unit is mu m; /(I)Is reservoir pressure, in MPa; /(I)、/>、/>、/>、/>、/>、/>、/>Are all experience parameters; /(I)The concentration of NaCl in the water phase is expressed in g/L; /(I)Temperature in K;
The total conductivity of the representative unit cell is:
（23）
In the method, in the process of the invention, To represent the total conductivity of the unit cell, the unit is S/m;
In combination with tortuosity, the overall conductivity of the representative unit body is reduced to:
（24）
In the method, in the process of the invention, Is the tortuosity of capillary bundles,/>And the method is dimensionless.
Preferably, in the step 6, since the miscible volumes of the supercritical carbon dioxide and the aqueous phase are related to the solubility of the supercritical carbon dioxide in the aqueous phase, the total volume of the miscible saturated capillary bundles dissolved in the aqueous phase in the porous medium model with a complex structure is set as shown in the formula (25):
（25）
wherein,
（26）
（27）
In the method, in the process of the invention,The total volume of the mixed phase saturated capillary bundles dissolved in the water phase in the conductivity model is determined; /(I)Is the volume fraction of supercritical carbon dioxide, and is dimensionless; /(I)Saturation for supercritical carbon dioxide; /(I)The unit of the solubility of supercritical carbon dioxide in NaCl-containing ionized water is mol/kg; /(I)The unit is mol/kg of solubility of supercritical carbon dioxide in water; /(I)Is a ternary action parameter of anions, cations and supercritical carbon dioxide; /(I)Is the molar mass concentration of sodium ions; /(I)The unit is mol/L of the molar mass concentration of chloride ions; /(I)Is a binary action parameter of supercritical carbon dioxide and water, has no dimension, and is a method for preparing the supercritical carbon dioxide waterWherein/>、/>、/>Are binary action coefficients and have no dimension;
The solubility of the supercritical carbon dioxide in the aqueous solution is as follows:
（28）
In the method, in the process of the invention, 、/>、/>、/>、/>、/>、/>Are all temperature related parameters, have no dimension, and have the calculation formula:
（29）
In the method, in the process of the invention, Is a temperature-related parameter,/>Is the sequence number of the temperature related parameter,/>And/>Is an integer; /(I)、/>、、/>、/>、/>The fitting coefficients are all supercritical carbon dioxide dissolution experiment fitting coefficients, and the fitting coefficients are dimensionless.
Preferably, in the inversion process of the complex-structure porous medium model, setting an error value, inverting the conductivity value according to the supercritical carbon dioxide saturation by using the complex-structure porous medium model, gradually increasing the supercritical carbon dioxide saturation value in the inversion process, stopping inversion calculation when the error between the conductivity value obtained by inversion calculation of the complex-structure porous medium model and the test conductivity is lower than a preset error value, and outputting the fluid saturation aperture and the supercritical carbon dioxide saturation obtained by inversion of the complex-structure porous medium model at different moments to obtain the change condition of the fluid saturation aperture and the supercritical carbon dioxide saturation of each phase.
The beneficial technical effects brought by the invention are as follows:
according to the sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity, the cross-section geometric shape of the real sandstone pores Mao Guanshu is reconstructed based on the fractal theory, and the simplified circular capillary bundle model is reconstructed into the rectangular capillary bundle model, so that the influence of the cross-section shape and the wall roughness of the capillary bundle is comprehensively considered, the capillary bundle model is more reasonable, and the capillary structure in sandstone can be accurately reproduced.
According to the sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity, the real simulation of complex porous media inside sandstone is realized by changing the amplification radius of the pore diameter Mao Guanshu in the representing unit body and considering capillary bundle models with different pore diameters, meanwhile, capillary bundle saturated fluids with different pores are classified, the influence of water-wet rock wall wettability and supercritical carbon dioxide on the capillary bundle models is represented, a partial saturation model conforming to the water-wet rock is constructed, and according to the influence of the water-wet rock wall wettability on the capillary bundle models, an ion flow, wetting wall ion exchange and supercritical carbon dioxide dissolution conductivity model is established, and the change of fluid saturation pore diameters and the change of supercritical carbon dioxide saturation of each phase in sandstone are obtained through inversion calculation.
The complex-structure porous medium model constructed by the invention can truly simulate the influence of porous medium structure and supercritical carbon dioxide dissolution in sandstone on rock conductivity, and can accurately monitor the change of the saturation of supercritical carbon dioxide when the sandstone reservoir is sealed.
Drawings
FIG. 1 is a flow chart of a method of conductivity-based sandstone reservoir supercritical carbon dioxide saturation calculation.
FIG. 2 is a schematic diagram of inversion results of a complex structured porous media model, luong model, and Archie model.
FIG. 3 is a graph of simulated conductivity versus measured conductivity for rock number one.
FIG. 4 is a graph of simulated conductivity versus measured conductivity for rock number two.
FIG. 5 is a graph of simulated conductivity versus measured conductivity for rock number three.
FIG. 6 is a graph of simulated conductivity versus measured conductivity for rock number four.
FIG. 7 is a graph of simulated versus measured conductivity of rock at a NaCl concentration of 0.2925 g/L.
FIG. 8 is a graph of simulated versus measured conductivity for rock at a NaCl concentration of 0.585 g/L.
FIG. 9 is a graph of simulated versus measured conductivity for rock at a NaCl concentration of 5.85 g/L.
FIG. 10 is a graph of simulated versus measured conductivity for rock at a NaCl concentration of 9.945 g/L.
FIG. 11 is a graph of simulated versus measured conductivity for rock at a NaCl concentration of 29.835 g/L.
FIG. 12 shows the fluid conductivity at various supercritical carbon dioxide saturation conditions at a NaCl concentration of 0.2925 g/L.
FIG. 13 shows the fluid conductivity at different supercritical carbon dioxide saturation levels at NaCl concentrations of 0.585 g/L.
FIG. 14 shows the fluid conductivity at different supercritical carbon dioxide saturation levels at NaCl concentrations of 5.85 g/L.
FIG. 15 shows the fluid conductivity at various supercritical carbon dioxide saturation conditions at NaCl concentrations 9.945 g/L.
FIG. 16 shows the fluid conductivity at various supercritical carbon dioxide saturation conditions at a NaCl concentration of 29.835 g/L.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Example 1
The embodiment discloses a sandstone reservoir supercritical carbon dioxide saturation calculating method based on conductivity, which comprises the following steps as shown in fig. 1:
Step 1, constructing a porous medium model with a complex structure according to the real structure of the porous medium, and representing the porous medium in the porous medium model with the complex structure based on a fractal theory.
In the step 1, based on the real structure of the porous medium, a distribution rule of pore sizes in the porous medium is obtained, as shown in a formula (1):
（1）
In the method, in the process of the invention, Is the total number of capillary bundles, and is dimensionless; /(I)The unit is mu m for the maximum capillary bundle radius in the sandstone porous medium; /(I)The unit is mu m for the capillary bundle radius in the sandstone porous medium; /(I)Fractal dimension of pore area, on two dimensionsAnd the method is dimensionless.
Deriving the formula (1) to obtain the relationship between the number of pores and the pore size in the pore radius range, as shown in the formula (2):
（2）
In the method, in the process of the invention, Mao Guanshu,/>, within an infinitely small rangeIs a pore in an infinitely small range.
Determining a total number of capillary bundles between a minimum capillary bundle radius and a maximum capillary bundle radius in a sandstone porous mediumThe method comprises the following steps:
（3）
In the method, in the process of the invention, Is the smallest Mao Guanshu radius in sandstone porous media, and has a unit of μm.
Combining equation (2) and equation (3) to obtain a probability density distribution function, as shown in equation (4):
（4）
In the method, in the process of the invention, Is a probability density function and is dimensionless.
Integrating probability density distribution function to determine the applicable condition of fractal theory to obtainOr/>When the fractal theory is adopted, the fractal theory formula is as follows:
（5）
wherein,
（6）
In the method, in the process of the invention,Is the porosity of the porous medium and is dimensionless.
And 2, constructing a rectangular capillary bundle model in the porous medium model with the complex structure, and setting the cross-sectional shape and the wall roughness of the capillary bundle model.
In the step 2, the micro conical structure is geometrically and uniformly distributed on the surface of the capillary bundle model, and is used for representing the rough surface of the capillary bundle wall surface, as shown in formula (7):
（7）
In the method, in the process of the invention, The average height of the mini cone is expressed in mu m; /(I)The height of the micro cone is expressed in mu m; /(I)Is the pore size length, in μm; /(I)The porous ceramic is coarse in porosity of the wall surface and is dimensionless.
Setting the true pore radius of the capillary bundle in the capillary bundle model, as shown in formula (8):
（8）
In the method, in the process of the invention, The unit is the minimum pore radius on the section of the unit in the real pore; /(I)The maximum pore radius is saturated by bound water in a real pore, and the unit is mu m; /(I)The maximum pore radius is saturated by water in real pores, and the unit is mu m; The maximum pore radius is saturated by the mixed phase of supercritical carbon dioxide and water in real pores, and the unit is mu m; /(I) The unit is the maximum pore radius on the section of the unit in the real pore; /(I)The true pore radius is expressed in mu m; /(I)The unit is mu m, which is the maximum pore radius of the mixed phase saturation of the supercritical carbon dioxide and water in the sandstone porous medium; /(I)The maximum pore radius of the binding water saturation in the sandstone porous medium is expressed in mu m.
And 3, selecting a substitution table unit body in the complex-structure porous medium model, and representing the amplification radii of different apertures Mao Guanshu in the unit body.
In the step 3, a surface unit body is selected and replaced in the complex-structure porous medium model, the amplification radius of different apertures Mao Guanshu in the representative unit body is changed, and the amplification deformation condition of the capillary bundles inside sandstone is represented.
Selecting a representative unit body, and calculating the total length of the bends Mao Guanshu in the representative unit body, as shown in formula (9):
（9）
In the method, in the process of the invention, Fractal dimension, two-dimensional space/>, of geometric tortuosity of capillary bundlesDimensionless; /(I)The total length of the bend Mao Guanshu is expressed in mu m; /(I)Average pore radius in μm; /(I)To represent the total length of the unit cell, the unit is μm.
The capillary bundle radii of different pore sizes were characterized as:
（10）
In the method, in the process of the invention, The maximum capillary bundle growth radius is the true pore, and the unit is mu m; /(I)The unit is mu m for the maximum capillary bundle growth radius; /(I)The maximum radius in μm representing the unit body of the largest pore Mao Guanshu among the true pores; /(I)The method is a capillary bundle radius change period and is dimensionless.
The volume of the single hair bundle is determined as follows:
（11）
In the method, in the process of the invention, The volume of the capillary bundle in the sandstone porous medium is expressed as mu m 3.
And 4, constructing the influence of wettability and miscible fluid on different pore diameters Mao Guanshu. Classifying capillary tube bundle saturated fluids with different apertures, characterizing the wettability of the wall surface of the water-wet rock and the influence of supercritical carbon dioxide and water mixing on each aperture Mao Guanshu, and respectively determining the total pore volume of the representative unit body and the total volume of bound capillary tube bundles, the total volume of water saturated capillary tube bundles, the total volume of mixed phase saturated capillary tube bundles and the total volume of supercritical carbon dioxide saturation Mao Guanshu in the representative unit body.
The calculation formula of the total pore volume of the representative unit body is as follows:
（12）
In the method, in the process of the invention, To represent the total pore volume of the unit cell, the unit is μm 3.
The calculation formula of the total volume of the restrained water capillary bundles in the representative unit body is as follows:
（13）
In the method, in the process of the invention, To represent the total volume of the bundled water capillary bundles inside the unit cell, the unit is μm 3.
The total volume calculation formula of the water saturated capillary bundles in the representative unit body is as follows:
（14）
In the method, in the process of the invention, To represent the total volume of water saturation Mao Guanshu inside the unit cell, the unit is μm 3.
The total volume calculation formula of the mixed phase saturated capillary bundles in the representative unit body is as follows:
（15）
In the method, in the process of the invention, To represent the total volume of miscible saturation Mao Guanshu within the unit cell, the unit is μm 3.
The calculation formula of the total volume of the supercritical carbon dioxide saturation Mao Guanshu in the representative unit body is as follows:
（16）
In the method, in the process of the invention, To represent the total volume of supercritical carbon dioxide saturation Mao Guanshu inside the unit cell, the unit is μm 3.
The irreducible water saturation, water phase saturation, miscible fluid saturation and supercritical carbon dioxide saturation of the representative unit are determined based on the total pore volume of the representative unit, the total volume of the bound water capillary bundle, the total volume of the water saturated capillary bundle, the total volume of the mixed phase saturated capillary bundle and the total volume of supercritical carbon dioxide saturation Mao Guanshu within the representative unit.
The calculation formula of the irreducible water saturation of the representative unit body is as follows:
（17）
In the method, in the process of the invention, To represent the irreducible water saturation of the unit cell.
The water phase saturation calculation formula of the representative unit body is as follows:
（18）
In the method, in the process of the invention, To represent the water phase saturation of the unit cell.
The formula for calculating the saturation of the mixed phase fluid of the representative unit body is as follows:
（19）
In the method, in the process of the invention, Representing the miscible fluid saturation of the unit cell.
The calculation formula of the supercritical carbon dioxide saturation of the representative unit body is as follows:
（20）
In the method, in the process of the invention, Is representative of the supercritical carbon dioxide saturation of the unit cell.
And 5, constructing a conductivity model considering ion flow, wetted wall ion exchange and supercritical carbon dioxide dissolution.
In the step 5, in the conductivity model, the resistivity of the water saturation Mao Guanshu is:
（21）
In the method, in the process of the invention, The resistivity of water saturation Mao Guanshu is expressed as omega-m; /(I)Is a form factor in μm; /(I)Saturated capillary radius for aqueous phase in μm; /(I)Specific surface conductivity of the water phase wetted wall surface ion exchange is S; /(I)To represent the cross-sectional area of the cell body, the unit is μm 2.
The resistivity of the supercritical carbon dioxide and water miscible phase saturation Mao Guanshu is:
（22）
In the method, in the process of the invention, The specific resistance of the water-carbon dioxide/water mixed phase saturation Mao Guanshu is omega-m; /(I)For normalizing the conductivity coefficient, dimensionless; /(I)Specific surface conductivity of the mixed phase wall surface ion exchange is S; /(I)Is the radius of a mixed phase saturated capillary, and the unit is mu m; /(I)Is reservoir pressure, in MPa; /(I)、/>、/>、/>、/>、/>、/>、/>Are all experience parameters; /(I)The concentration of NaCl in the water phase is expressed in g/L; /(I)Temperature, in K.
The total conductivity of the representative unit cell is:
（23）
In the method, in the process of the invention, To represent the total conductivity of the unit cell, the unit is S/m.
In combination with tortuosity, the overall conductivity of the representative unit body is reduced to:
（24）
In the method, in the process of the invention, Is the tortuosity of capillary bundles,/>And the method is dimensionless.
And 6, inverting by using a porous medium model with a complex structure to obtain the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid at different moments, and obtaining the change condition of the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid.
In the step 6, since the miscible volume of the supercritical carbon dioxide and the aqueous phase is related to the solubility of the supercritical carbon dioxide in the aqueous phase, the total volume of the miscible saturated capillary bundles dissolved in the aqueous phase in the porous medium model with a complex structure is set as shown in the formula (25):
（25）
wherein,
（26）
（27）
In the method, in the process of the invention,The total volume of the mixed phase saturated capillary bundles dissolved in the water phase in the conductivity model is determined; /(I)Is the volume fraction of supercritical carbon dioxide, and is dimensionless; /(I)Saturation for supercritical carbon dioxide; /(I)The unit of the solubility of supercritical carbon dioxide in NaCl-containing ionized water is mol/kg; /(I)The unit is mol/kg of solubility of supercritical carbon dioxide in water; /(I)Is a ternary action parameter of anions, cations and supercritical carbon dioxide; /(I)Is the molar mass concentration of sodium ions; /(I)The unit is mol/L of the molar mass concentration of chloride ions; /(I)Is a binary action parameter of supercritical carbon dioxide and water, has no dimension, and is a method for preparing the supercritical carbon dioxide waterWherein/>、/>、/>All are binary action coefficients and have no dimension.
The solubility of the supercritical carbon dioxide in the aqueous solution is as follows:
（28）
In the method, in the process of the invention, 、/>、/>、/>、/>、/>、/>Are all temperature related parameters, have no dimension, and have the calculation formula:
（29）
In the method, in the process of the invention, Is a temperature-related parameter,/>Is the sequence number of the temperature related parameter,/>And/>Is an integer; /(I)、/>、、/>、/>、/>The fitting coefficients are all supercritical carbon dioxide dissolution experiment fitting coefficients, and the fitting coefficients are dimensionless.
Setting an error value in the inversion process of the complex-structure porous medium model, utilizing the complex-structure porous medium model to invert the conductivity value according to the supercritical carbon dioxide saturation, gradually increasing the saturation value of the supercritical carbon dioxide in the inversion process, stopping inversion calculation when the error between the conductivity value obtained by inversion calculation of the complex-structure porous medium model and the test conductivity is lower than a preset error value, and outputting fluid saturated pore diameters and supercritical carbon dioxide saturation obtained by inversion of the complex-structure porous medium model at different times to obtain the change condition of fluid saturated pore diameters and supercritical carbon dioxide saturation of each phase.
Example 2
To further verify the effectiveness of the method of the present invention, the complex structured porous media model of example 1 was compared to Luong model and Archie model, the maximum pore radius of the rocks in the complex structured porous media model, luong model and Archie model was set to 50 μm, the porosity was set to 0.05-0.5, the ratio of the minimum pore radius to the maximum pore radius was set to 0.01, the wetted wall ion exchange conductivity was set to 1×10 -4 S/m, the conductivity of the aqueous phase was set to 5×10 -2 S/m, the cementation index was set to 1.5, and the water saturation was set to 100%.
Comparing inversion results of the porous medium model with a complex structure, the Luong model and the Archie model, as shown in fig. 2, the conductivity calculation result of the model is found to be larger than that of the Luong model and the Archie model, because the model reconstructs the cross-section geometric shape of a real sandstone pore Mao Guanshu, and the influence of wetting wall ion exchange on conductivity is comprehensively considered under the condition of amplifying and deforming capillary bundle radius representing different sizes of the unit body.
Example 3
In order to further verify the effect of the method of the present invention, in this embodiment, for four core samples, core conductivity simulation is performed by using the porous medium model with the complex structure in embodiment 1, and the core conductivity is compared with the actually measured conductivity of the core.
In the embodiment, the porosity of the porous medium model with the complex structure is set to be 0.4, the conductivity of the water phase is set to be between 10 -4 and 0.1S/m, the ion exchange conductivity of the wetted wall surface is set to be 5 multiplied by 10 -4 S/m, the ratio of the minimum pore radius to the maximum pore radius is set to be 0.01, the water saturation is set to be 100%, and the four rocks are numbered respectively to obtain a first rock, a second rock, a third rock and a fourth rock, wherein the maximum pore radius of the first rock is 28 mu m, the maximum pore radius of the second rock is 46.5 mu m, the maximum pore radius of the third rock is 90.5 mu m, and the maximum pore radius of the fourth rock is 128 mu m.
Fig. 3 is a graph of comparing the simulated conductivity and the measured conductivity of the first rock, fig. 4 is a graph of comparing the simulated conductivity and the measured conductivity of the second rock, fig. 5 is a graph of comparing the simulated conductivity and the measured conductivity of the third rock, and fig. 6 is a graph of comparing the simulated conductivity and the measured conductivity of the fourth rock, and after comparing the graphs, it is found that the calculated conductivity and the measured conductivity of the complex-structure porous medium model constructed by the method of the invention have higher fitting degree, so that the accuracy of calculating the complex-structure porous medium model constructed by the method of the invention is verified.
Example 4
In order to further verify the effect of the method, in the embodiment, rock conductivity under different NaCl concentration conditions and supercritical carbon dioxide saturation conditions is respectively simulated by using the complex-structure porous medium model in the embodiment 1, and the rock conductivity is compared with the actual measured conductivity of the rock core.
Five core samples are selected in the embodiment, the NaCl concentration in the water phase of each core sample is different, the conductivity of the salt solution is also different, the NaCl concentration is respectively set to 0.2925g/L, 0.585g/L, 5.85g/L, 9.945g/L and 29.835g/L, and the conductivity of the corresponding salt solution is respectively 5X 10 -2 S/m、1×10-1 S/m, 1S/m, 1.7S/m and 5.1S/m.
The simulated conductivities of the rock are obtained by simulating the porous medium model with the complex structure according to 0.2925g/L, 0.585g/L, 5.85g/L, 9.945g/L and 29.835g/L respectively, and are compared with the measured conductivities to obtain the graphs 7-11, and after comparing the graphs 7-11, the matching degree of the calculated conductivities and the measured conductivities of the porous medium model with the complex structure constructed by the method is higher, namely the matching degree of the calculated result and the experimental result of the rock conductivity of the model is better under the condition of different mineralizations.
Meanwhile, the porosity of the complex-structure porous medium model is further set to be 0.2 for the water phase and the oil phase, the water phase wall surface ion exchange is 1 multiplied by 10 -4 S/m, the mixed phase wall surface ion exchange is 7 multiplied by 10 -4 S/m, the experimental temperature is 43 ℃, the pressure is 8MPa, and the complex-structure porous medium model is used for simulating to obtain the conductivities of various phases of fluid under different supercritical carbon dioxide saturation conditions when the NaCl concentration is 0.2925g/L, 0.585g/L, 5.85g/L, 9.945g/L and 29.835g/L respectively, as shown in fig. 12-16, the fitting degree of the rock conductivity calculation result and the experimental result of the model under different supercritical carbon dioxide saturation conditions is better, so that the conductivity contribution values of different fluids can be accurately calculated by verifying the complex-structure porous medium model constructed by the method.
It should be understood that the above description is not intended to limit the invention to the particular embodiments disclosed, but to limit the invention to the particular embodiments disclosed, and that the invention is not limited to the particular embodiments disclosed, but is intended to cover modifications, adaptations, additions and alternatives falling within the spirit and scope of the invention.
Claims (2)
1. The sandstone reservoir supercritical carbon dioxide saturation calculating method based on conductivity is characterized by comprising the following steps of:
step 1, constructing a porous medium model with a complex structure according to the real structure of the porous medium, and representing the porous medium in the porous medium model with the complex structure based on a fractal theory;
Step 2, constructing a rectangular capillary bundle model in the porous medium model with the complex structure, and setting the cross-sectional shape and the wall roughness of the capillary bundle model;
Step 3, selecting a substitution table unit body in the complex structure porous medium model, and representing the amplification radii of different apertures Mao Guanshu in the unit body;
step 4, constructing the influence of wettability and miscible fluid on different pore diameters Mao Guanshu;
Step 5, constructing a conductivity model considering ion flow, wetted wall ion exchange and supercritical carbon dioxide dissolution;
Step 6, inverting by utilizing a porous medium model with a complex structure to obtain the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid at different moments, and obtaining the change condition of the saturated aperture and the supercritical carbon dioxide saturation of each phase of fluid;
in the step 1, based on the real structure of the porous medium, a distribution rule of pore sizes in the porous medium is obtained, as shown in a formula (1):
（1）
In the method, in the process of the invention, Is the total number of capillary bundles, and is dimensionless; /(I)The unit is mu m for the maximum capillary bundle radius in the sandstone porous medium; /(I)The unit is mu m for the capillary bundle radius in the sandstone porous medium; /(I)Fractal dimension of pore area, on two dimensionsDimensionless;
Deriving the formula (1) to obtain the relationship between the number of pores and the pore size in the pore radius range, as shown in the formula (2):
（2）
In the method, in the process of the invention, Mao Guanshu,/>, within an infinitely small rangeIs an aperture in an infinitely small range;
determining a total number of capillary bundles between a minimum capillary bundle radius and a maximum capillary bundle radius in a sandstone porous medium The method comprises the following steps:
（3）
In the method, in the process of the invention, Is the smallest Mao Guanshu radius in the sandstone porous medium, and the unit is mu m;
combining equation (2) and equation (3) to obtain a probability density distribution function, as shown in equation (4):
（4）
In the method, in the process of the invention, Is a probability density function and is dimensionless;
integrating probability density distribution function to determine the applicable condition of fractal theory to obtain Or/>When the fractal theory is adopted, the fractal theory formula is as follows:
（5）
wherein,
（6）
In the method, in the process of the invention,Is the porosity of the porous medium, and is dimensionless;
In the step 2, the micro conical structure is geometrically and uniformly distributed on the surface of the capillary bundle model, and is used for representing the rough surface of the capillary bundle wall surface, as shown in formula (7):
（7）
In the method, in the process of the invention, The average height of the mini cone is expressed in mu m; /(I)The height of the micro cone is expressed in mu m; /(I)Is the pore size length, in μm; /(I)The coarse porosity of the wall surface is dimensionless;
setting the true pore radius of the capillary bundle in the capillary bundle model, as shown in formula (8):
（8）
In the method, in the process of the invention, The unit is the minimum pore radius on the section of the unit in the real pore; /(I)The maximum pore radius is saturated by bound water in a real pore, and the unit is mu m; /(I)The maximum pore radius is saturated by water in real pores, and the unit is mu m; The maximum pore radius is saturated by the mixed phase of supercritical carbon dioxide and water in real pores, and the unit is mu m; /(I) The unit is the maximum pore radius on the section of the unit in the real pore; /(I)The true pore radius is expressed in mu m; /(I)The unit is mu m, which is the maximum pore radius of the mixed phase saturation of the supercritical carbon dioxide and water in the sandstone porous medium; /(I)The maximum pore radius of the water saturation is bound in the sandstone porous medium, and the unit is mu m;
In the step 3, a surface unit body is selected and replaced in the complex-structure porous medium model, the amplification radius of different apertures Mao Guanshu in the representative unit body is changed, and the amplification deformation condition of the capillary bundles inside sandstone is represented;
selecting a representative unit body, and calculating the total length of the bends Mao Guanshu in the representative unit body, as shown in formula (9):
（9）
In the method, in the process of the invention, Fractal dimension, two-dimensional space/>, of geometric tortuosity of capillary bundlesDimensionless; /(I)The total length of the bend Mao Guanshu is expressed in mu m; /(I)Average pore radius in μm; /(I)To represent the total length of the unit cell, the units are μm;
The capillary bundle radii of different pore sizes were characterized as:
（10）
In the method, in the process of the invention, The maximum capillary bundle growth radius is the true pore, and the unit is mu m; /(I)The unit is mu m for the maximum capillary bundle growth radius; /(I)The maximum radius in μm representing the unit body of the largest pore Mao Guanshu among the true pores; /(I)The method is a capillary bundle radius change period and is dimensionless;
The volume of the single hair bundle is determined as follows:
（11）
In the method, in the process of the invention, The volume of the capillary bundle in the sandstone porous medium is shown as mu m 3;
In the step 4, classifying capillary tube bundle saturated fluids with different apertures, and representing the wettability of the wall surface of the water-wet rock and the influence of supercritical carbon dioxide and water mixing on each aperture Mao Guanshu;
Respectively determining the total pore volume of the representative unit body, the total volume of the restrained capillary tube bundle, the total volume of the water saturated capillary tube bundle, the total volume of the mixed phase saturated capillary tube bundle and the total volume of supercritical carbon dioxide saturation Mao Guanshu;
The calculation formula of the total pore volume of the representative unit body is as follows:
（12）
In the method, in the process of the invention, To represent the total pore volume of the unit cell, in μm 3;
The calculation formula of the total volume of the restrained water capillary bundles in the representative unit body is as follows:
（13）
In the method, in the process of the invention, The unit is mu m 3 for representing the total volume of the restrained capillary bundles inside the unit body;
The total volume calculation formula of the water saturated capillary bundles in the representative unit body is as follows:
（14）
In the method, in the process of the invention, To represent the total volume of water saturation Mao Guanshu inside the unit cell, the unit is μm 3;
the total volume calculation formula of the mixed phase saturated capillary bundles in the representative unit body is as follows:
（15）
In the method, in the process of the invention, To represent the total volume of miscible saturation Mao Guanshu inside the unit cell, the unit is μm 3;
the calculation formula of the total volume of the supercritical carbon dioxide saturation Mao Guanshu in the representative unit body is as follows:
（16）
In the method, in the process of the invention, To represent the total volume of supercritical carbon dioxide saturation Mao Guanshu inside the unit cell, the unit is μm 3;
Determining the irreducible water saturation, the water phase saturation, the miscible fluid saturation and the supercritical carbon dioxide saturation of the representative unit based on the total pore volume of the representative unit, the total volume of the bound capillary bundle, the total volume of the water saturated capillary bundle, the total volume of the mixed phase saturated capillary bundle and the total volume of the supercritical carbon dioxide saturation Mao Guanshu inside the representative unit;
the calculation formula of the irreducible water saturation of the representative unit body is as follows:
（17）
In the method, in the process of the invention, To represent the irreducible water saturation of the unit cell;
the water phase saturation calculation formula of the representative unit body is as follows:
（18）
In the method, in the process of the invention, Water phase saturation representing the unit cell;
the formula for calculating the saturation of the mixed phase fluid of the representative unit body is as follows:
（19）
In the method, in the process of the invention, To represent the miscible fluid saturation of the unit cell;
the calculation formula of the supercritical carbon dioxide saturation of the representative unit body is as follows:
（20）
In the method, in the process of the invention, Is the supercritical carbon dioxide saturation representing the unit cell;
in the step 5, in the conductivity model, the resistivity of the water saturation Mao Guanshu is:
（21）
In the method, in the process of the invention, The resistivity of water saturation Mao Guanshu is expressed as omega-m; /(I)Is a form factor in μm; /(I)Saturated capillary radius for aqueous phase in μm; /(I)Specific surface conductivity of the water phase wetted wall surface ion exchange is S; /(I)To represent the cross-sectional area of the cell body, the unit is μm 2;
the resistivity of the supercritical carbon dioxide and water miscible phase saturation Mao Guanshu is:
（22）
In the method, in the process of the invention, The specific resistance of the water-carbon dioxide/water mixed phase saturation Mao Guanshu is omega-m; /(I)For normalizing the conductivity coefficient, dimensionless; /(I)Specific surface conductivity of the mixed phase wall surface ion exchange is S; /(I)Is the radius of a mixed phase saturated capillary, and the unit is mu m; /(I)Is reservoir pressure, in MPa; /(I)、/>、/>、/>、/>、/>、/>、/>Are all experience parameters; /(I)The concentration of NaCl in the water phase is expressed in g/L; /(I)Temperature in K;
The total conductivity of the representative unit cell is:
（23）
In the method, in the process of the invention, To represent the total conductivity of the unit cell, the unit is S/m;
In combination with tortuosity, the overall conductivity of the representative unit body is reduced to:
（24）
In the method, in the process of the invention, Is the tortuosity of capillary bundles,/>Dimensionless;
In the step 6, since the miscible volume of the supercritical carbon dioxide and the aqueous phase is related to the solubility of the supercritical carbon dioxide in the aqueous phase, the total volume of the miscible saturated capillary bundles dissolved in the aqueous phase in the porous medium model with a complex structure is set as shown in the formula (25):
（25）
wherein,
（26）
（27）
In the method, in the process of the invention,The total volume of the mixed phase saturated capillary bundles dissolved in the water phase in the conductivity model is determined; /(I)Is the volume fraction of supercritical carbon dioxide, and is dimensionless; /(I)Saturation for supercritical carbon dioxide; /(I)The unit of the solubility of supercritical carbon dioxide in NaCl-containing ionized water is mol/kg; /(I)The unit is mol/kg of solubility of supercritical carbon dioxide in water; /(I)Is a ternary action parameter of anions, cations and supercritical carbon dioxide; /(I)Is the molar mass concentration of sodium ions; /(I)The unit is mol/L of the molar mass concentration of chloride ions; /(I)Is a binary action parameter of supercritical carbon dioxide and water, has no dimension, and is a method for preparing the supercritical carbon dioxide waterWherein/>、/>、/>Are binary action coefficients and have no dimension;
The solubility of the supercritical carbon dioxide in the aqueous solution is as follows:
（28）
In the method, in the process of the invention, 、/>、/>、/>、/>、/>、/>Are all temperature related parameters, have no dimension, and have the calculation formula:
（29）
In the method, in the process of the invention, Is a temperature-related parameter,/>Is the sequence number of the temperature related parameter,/>And/>Is an integer; /(I)、/>、/>、、/>、/>The fitting coefficients are all supercritical carbon dioxide dissolution experiment fitting coefficients, and the fitting coefficients are dimensionless.
2. The sandstone reservoir supercritical carbon dioxide saturation calculation method based on conductivity of claim 1, wherein in the inversion process of the complex-structure porous medium model, an error value is set, the complex-structure porous medium model is utilized to invert the conductivity value according to the supercritical carbon dioxide saturation, the saturation value of the supercritical carbon dioxide is gradually increased in the inversion process, when the error between the conductivity value obtained by inversion calculation of the complex-structure porous medium model and the tested conductivity is lower than a preset error value, the inversion calculation is stopped, the fluid saturated pore diameter and the supercritical carbon dioxide saturation obtained by inversion of the complex-structure porous medium model at different moments are output, and the change condition of the fluid saturated pore diameter and the supercritical carbon dioxide saturation of each phase is obtained.
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| US20160146969A1 (en) * | 2014-11-24 | 2016-05-26 | King Fahd University Of Petroleum And Minerals | Method of monitoring carbon dioxide leakage in carbon capture and storage reservoirs |
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| WO2021180189A1 (en) * | 2020-03-13 | 2021-09-16 | 重庆科技学院 | Multi-element thermal fluid thermal recovery oil reservoir numerical simulation method |
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