CN108505991B - Method and device for determining extraction degree of oil in rock core - Google Patents
Method and device for determining extraction degree of oil in rock core Download PDFInfo
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- CN108505991B CN108505991B CN201810122003.0A CN201810122003A CN108505991B CN 108505991 B CN108505991 B CN 108505991B CN 201810122003 A CN201810122003 A CN 201810122003A CN 108505991 B CN108505991 B CN 108505991B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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Abstract
The embodiment of the application discloses a method and a device for determining the extraction degree of oil in a rock core. The method comprises the following steps: determining a target capillary radius of a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in a single capillary at a specified displacement pressure differential; determining the extraction degree of oil in the single capillary under the specified displacement differential pressure based on the target capillary radius; and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core. According to the technical scheme provided by the embodiment of the application, the accuracy of the extraction degree of the oil in the determined rock core can be improved.
Description
Technical Field
The application relates to the technical field of oil reservoir development, in particular to a method and a device for determining the extraction degree of oil in a rock core.
Background
Chinese dense oil resources are rich, the amount of the dense oil resources in the main basin is initially evaluated to be 80-100 hundred million tons, and the dense oil becomes an important succesive resource. In order to realize the high-efficiency commercial development of the compact oil reservoir, a large-scale horizontal well staged fracturing modification technology is adopted, ten thousand square water is injected to 'break the reservoir', the seepage distance between the fracture and the matrix is shortened, and the yield-increasing modification effect is achieved.
The current mine field experiment results show that the water storage rate of a reservoir can be increased by not flowing back after the compact oil reservoir is pressurized, stopping the pump and stewing for a period of time, and then, more matrix crude oil is replaced by imbibition under the combined action of displacement pressure difference and capillary force generated in the fracturing fluid filtration process, so that the crude oil recovery rate is improved. However, the micro-pore structure of the water-wet compact core is complex, and how to accurately obtain the extraction degree of the oil in the water-wet compact core under a certain displacement pressure difference is used for optimizing a proper displacement pressure difference, so that the extraction degree of the compact core under the combined action of the displacement pressure difference and the tubular force is the highest, and the method is of great importance for improving the recovery ratio of the compact oil reservoir.
At present, the conventional method for determining the extraction degree of oil in a water-wet compact rock core mainly simulates the spontaneous imbibition water displacement process of the rock core through a water displacement theoretical model established based on a piston type water displacement model, so that the extraction degree of the oil in the rock core is determined. However, the model does not consider the unique micro-nano micro-pore structure characteristics of the compact core completely, which may result in low accuracy of the oil extraction degree in the determined water-wet compact core, and thus, the reasonable displacement pressure difference is difficult to be accurately and preferably selected.
Disclosure of Invention
An object of the embodiments of the present application is to provide a method and an apparatus for determining a recovery degree of oil in a core, so as to improve accuracy of the determined recovery degree of oil in the core.
In order to solve the above technical problem, an embodiment of the present application provides a method and an apparatus for determining a recovery degree of oil in a core, which are implemented as follows:
a method for determining the extraction degree of oil in a rock core is provided with a capillary tube bundle for representing the pore structure of the rock core in a target work area and initial capillary radius distribution data of the capillary tube bundle; the method comprises the following steps:
determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
determining a degree of production of oil from the single capillary at a specified displacement pressure differential based on the target capillary radius;
and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
In a preferred embodiment, determining a target capillary radius of a single capillary in the capillary bundle based on the initial capillary radius distribution data comprises:
determining a boundary layer thickness at which fluid imbibes in the single capillary at a specified displacement differential pressure;
and acquiring the initial capillary radius of the single capillary from the initial capillary radius distribution data, and subtracting the thickness of the boundary layer from the initial capillary radius to obtain the target capillary radius of the single capillary.
In a preferred scheme, the boundary layer thickness of the fluid in the single capillary tube for seepage under a specified displacement pressure difference is determined by the following formula:
δi＝δ0+r0i·exp(-B·(Δp)-C)
wherein, deltaiRepresents the boundary layer thickness, δ, of the fluid imbibed in the ith single capillary in the capillary bundle0Indicates the thickness of the fluid boundary solidified layer, r0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, Δ p represents the specified displacement pressure differential, B represents a parameter associated with the material of the wall of the single capillary, and C represents a parameter associated with the viscosity of the fluid.
In a preferred embodiment, the oil production level in the single capillary at a given displacement pressure difference is determined using the following formula:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
In a preferred embodiment, the extent of oil production from the capillary bundle at the specified displacement pressure differential is determined using the following equation:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
An apparatus for determining the extent of oil production from a core, the apparatus providing a capillary bundle for characterizing the pore structure of the core in a work area of interest, and initial capillary radius distribution data for the capillary bundle; the device comprises: the device comprises a target radius determining module, a single capillary extraction degree determining module and a rock core extraction degree determining module; wherein the content of the first and second substances,
the target radius determination module is used for determining the target capillary radius of the single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
the single-capillary extraction degree determining module is used for determining the extraction degree of the oil in the single capillary under the specified displacement pressure difference based on the target capillary radius;
and the core extraction degree determining module is used for determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the core.
In a preferred embodiment, the target radius determining module is configured to determine a boundary layer thickness when fluid is imbibed in the single capillary under a specified displacement pressure difference, obtain an initial capillary radius of the single capillary from the initial capillary radius distribution data, and subtract the boundary layer thickness from the initial capillary radius to obtain a target capillary radius of the single capillary.
In a preferred embodiment, the single capillary extraction degree determining module is configured to determine the extraction degree of oil in the single capillary at a specified displacement pressure difference by using the following formula:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwIs indicative of the viscosity of the wetting phase in said fluid,Δ p represents the specified displacement pressure differential, σ represents the interfacial tension between the wetting and non-wetting phases in the fluid, θ represents the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
In a preferred embodiment, the core extraction degree determining module is configured to determine the extraction degree of oil in the capillary bundle under the specified displacement pressure difference by using the following formula:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
An apparatus for determining the extent of oil production from a core, comprising a memory, a processor, and a computer program stored on the memory, the memory having stored therein a capillary bundle for characterizing the pore structure of the core in a work area of interest, and initial capillary radius distribution data for the capillary bundle, the computer program when executed by the processor performing the steps of:
determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
determining a degree of production of oil from the single capillary at a specified displacement pressure differential based on the target capillary radius;
and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
According to the technical scheme provided by the embodiment of the application, the embodiment of the application provides a method and a device for determining the extraction degree of oil in a rock core, the pore structure of the rock core in a target work area is represented by a capillary tube bundle, wherein the capillary tube bundle has the distribution characteristic of the capillary tube radius represented by initial capillary tube radius distribution data, so that the unique micro-nano micro pore structure characteristic in a compact rock core can be considered more comprehensively, and the extraction degree of the oil in the capillary tube bundle is taken as the extraction degree of the oil in the rock core, so that the accuracy of the determined extraction degree of the oil in the rock core can be improved; moreover, the extraction degree of the oil in the single capillary tube under the specified displacement pressure difference is determined according to the target capillary tube radius of the single capillary tube in the capillary tube bundle, wherein the target capillary tube radius is used for representing the radius of an effective flow channel when the fluid is subjected to imbibition in the single capillary tube under the specified displacement pressure difference, and the radius of the effective flow channel is more consistent with an actual channel when the fluid is subjected to imbibition in a rock core.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.
FIG. 1 is a flow chart of an embodiment of a method of determining a production level of oil in a core according to the present application;
FIG. 2 is a schematic illustration of imbibition of a fluid in a single capillary at a specified displacement pressure differential in an embodiment of the application;
FIG. 3 is a schematic diagram of a variation relationship between maximum extraction degrees and a specified displacement pressure difference, which is obtained by a simulation calculation method and an experiment method of the present application respectively in an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating the components of one embodiment of an apparatus for determining the extent of oil production from a core according to the present disclosure;
fig. 5 is a schematic diagram of a composition of another embodiment of the apparatus for determining the extent of oil production from a core of the present application.
Detailed Description
The embodiment of the application provides a method and a device for determining the extraction degree of oil in a rock core.
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides a method for determining the extraction degree of oil in a rock core. The method for determining the extraction degree of oil in the core is provided with a capillary bundle for representing the pore structure of the core in a target work area and initial capillary radius distribution data of the capillary bundle.
In this embodiment, the core in the target work area may be a tight sandstone core, such as a quartzite feldspar sandstone core.
In the embodiment, since the pore structure in the compact core is mostly a micro-nano pore system, the spontaneous imbibition displacement process is relatively slow, and the imbibition displacement process can be effectively characterized by adopting a capillary tube model. Thus, a capillary bundle with certain capillary radius distribution characteristics can be adopted to characterize the pore structure of the core in the target work area. The capillary bundle can be composed of mutually independent parallel capillaries, and the initial capillary radius distribution data of the capillary bundle can be the capillary radius distribution data meeting the normal distribution rule.
FIG. 1 is a flow chart of an embodiment of a method of determining the extent of oil production in a core according to the present application. As shown in fig. 1, the method for determining the extraction degree of oil in the core comprises the following steps.
Step S101: determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement pressure differential.
In this embodiment, determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data may specifically include determining a boundary layer thickness at which fluid imbibes in the single capillary at a specified displacement pressure differential. Wherein the value range of the specified displacement pressure difference can comprise 1 MPa to 10 MPa. An initial capillary radius of the single capillary may be obtained from the initial capillary radius distribution data, and the boundary layer thickness may be subtracted from the initial capillary radius to obtain a target capillary radius of the single capillary. Wherein the target capillary radius may be used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement pressure differential. The fluid may be a mixture of water and oil.
In this embodiment, the boundary layer thickness at which fluid imbibes in the single capillary at a given displacement differential pressure may be determined using the following equation:
δi＝δ0+r0i·exp(-B·(Δp)-C)
wherein, deltaiRepresents the boundary layer thickness, δ, of the fluid imbibed in the ith single capillary in the capillary bundle0Indicates the thickness of the fluid boundary solidified layer, r0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, Δ p represents the specified displacement pressure differential, B represents a parameter associated with the material of the wall of the single capillary, and C represents a parameter associated with the viscosity of the fluid.
Step S102: based on the target capillary radius, a degree of production of oil from the single capillary at a specified displacement pressure differential is determined.
In this embodiment, based on the target capillary radius, the extent of oil production in the single capillary at a given displacement differential pressure may be determined using the following equation:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time. Specifically, the imbibition process of a fluid in a single capillary at a specified displacement pressure difference as shown in fig. 2, the single capillary displacement imbibition model can be characterized using the following formula:
wherein p isciRepresents the capillary pressure, L, within the ith single capillary in the capillary bundleiRepresents the movement distance, μ, of the wetting phase of the fluid in the ith monocapillary tube in the capillary bundlenwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time. L in FIG. 2 denotes the distance of movement of the wetting phase of the fluid in the monocapillary tube, qwIndicates the amount of water injected, qoThe oil production is indicated.
Equations (2) and (3) can be substituted into equation (1) to yield:
the two sides of equation (4) can be integrated separately to obtain:
solving equation (5) can yield:
according to formula (6)
Obtaining the extraction degree of oil in the single capillary under the specified displacement pressure difference:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
Step S103: and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
In this embodiment, based on the oil production level in each of the single capillaries in the capillary bundle at the specified displacement pressure difference, the oil production level in the capillary bundle at the specified displacement pressure difference can be determined by using the following formula:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
In this embodiment, the extent of oil production from the capillary bundle may be used as the extent of oil production from the core.
In one embodiment of the present application, the method for determining the extraction degree of oil from the core may further include: the maximum extraction degree of the oil in the rock core under a plurality of specified displacement pressure differences can be respectively determined according to the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure differences; and determining the optimal displacement pressure difference according to the maximum extraction degree of the oil in the rock core under a plurality of specified displacement pressure differences. Specifically, for example, the specified displacement pressure differences may be 1 mpa, 3 mpa, 5 mpa, and 7 mpa, respectively determining a variation curve of the oil extraction degree of the core with the imbibition time under the specified displacement pressure differences, and taking the oil extraction degree when the oil extraction degree is close to stability as the maximum extraction degree, so as to obtain the maximum extraction degree of the oil in the core respectively under the specified displacement pressure differences of 1 mpa, 3 mpa, 5 mpa, and 7 mpa, as shown in the calculation result in fig. 3, because the maximum extraction degree of the oil in the core changes relatively slowly when the specified displacement pressure difference is greater than or equal to 3 mpa, the specified displacement pressure difference with the displacement pressure difference of 3 mpa may be taken as the optimal displacement pressure difference. Wherein the abscissa and ordinate in fig. 3 are the displacement pressure difference and the maximum production degree, respectively, in units of mpa and percent (%).
In order to verify the accuracy of the method for determining the extraction degree of oil in the rock core, 4 compact sandstone core samples with similar physical properties can be selected to perform a constant-pressure water flooding physical simulation experiment. For example, the 4 tight sandstone core samples all belong to the quartziferous feldspar sandstone, wherein the clay minerals mainly comprise three types of illite, chlorite and illite/montmorillonite mixed layer. Before the experiment, the oil washing treatment and the drying treatment can be firstly carried out on the core sample in the shape of a column, then a small section (for example, the height is 1-2 cm) is cut out from the end face of the core sample to measure the contact angle, and the vacuum pumping and the pressurization saturated oil treatment are carried out on the rest part (for example, the height is 4-5 cm). Wherein the oil may be kerosene. After the 4 tight sandstone core samples are processed before the experiment, a constant-pressure water flooding physical simulation experiment is respectively carried out on the 4 tight sandstone core samples by using a displacement-low magnetic field resonance integrated device (for example, a displacement-low magnetic field resonance integrated device with the device model number of MesoMR 23-060H-HTHP-I). In the experimental process, a deuterium aqueous solution of potassium chloride with the concentration of 2% is continuously injected into the inlet end of the equipment, the displacement pressure difference is 1 MPa, 3 MPa, 5 MPa and 7 MPa in sequence, and the low-field nuclear magnetism T is monitored once every 30-60 minutes2Spectrum signal, and T to be monitored2Converting the spectrum signal into the quality of kerosene, and calculating the extraction degree of the kerosene by adopting the following formula:
wherein R isoilRepresents the degree of extraction of kerosene, m0Represents the mass m of saturated kerosene in the core sample before the constant pressure water flooding physical simulation experimentjAnd the mass of the residual kerosene in the rock core sample measured at the j moment in the process of carrying out the constant-pressure water flooding physical simulation experiment is shown. According to the experimental results, the maximum extraction degree of the oil in the rock core under the displacement pressure difference of 1 MPa, 3 MPa, 5 MPa and 7 MPa can be respectively obtained, wherein the experimental knot in the figure 3As shown in the result, when the displacement pressure difference is greater than or equal to 3 mpa, the maximum extraction degree of the oil in the core is basically unchanged, and the specified displacement pressure difference with the displacement pressure difference of 3 mpa can be used as the optimal displacement pressure difference. Therefore, the result obtained by the method is basically consistent with the experimental result, and the method for determining the oil extraction degree in the rock core has higher accuracy.
In the method for determining the extraction degree of the oil in the rock core, the pore structure of the rock core in a target work area is represented by the capillary tube bundle, wherein the capillary tube bundle has the distribution characteristic of the capillary radius represented by initial capillary radius distribution data, so that the unique micro-nano micro pore structure characteristic in the compact rock core can be considered more comprehensively, and the extraction degree of the oil in the capillary tube bundle is taken as the extraction degree of the oil in the rock core, so that the accuracy of the determined extraction degree of the oil in the rock core can be improved; moreover, the extraction degree of the oil in the single capillary tube under the specified displacement pressure difference is determined according to the target capillary tube radius of the single capillary tube in the capillary tube bundle, wherein the target capillary tube radius is used for representing the radius of an effective flow channel when the fluid is subjected to imbibition in the single capillary tube under the specified displacement pressure difference, and the radius of the effective flow channel is more consistent with an actual channel when the fluid is subjected to imbibition in a rock core.
FIG. 4 is a schematic diagram illustrating the components of one embodiment of the apparatus for determining the extent of oil production from a core of the present application. The device for determining the extraction degree of oil in the rock core provides a capillary tube bundle for representing the pore structure of the rock core in a target work area and initial capillary radius distribution data of the capillary tube bundle. As shown in fig. 4, the apparatus for determining the extent of oil production in a core may include: the system comprises a target radius determination module 100, a single capillary extraction degree determination module 200 and a core extraction degree determination module 300.
The target radius determination module 100 may be configured to determine a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement pressure differential.
The single-capillary extraction degree determination module 200 may be configured to determine an extraction degree of oil in the single capillary at a specified displacement pressure difference based on the target capillary radius.
The core extraction degree determining module 300 may be configured to determine the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and use the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the core.
In this embodiment, the target radius determination module 100 may be configured to determine a boundary layer thickness when a fluid is imbibed in the single capillary under a specified displacement pressure difference, obtain an initial capillary radius of the single capillary from the initial capillary radius distribution data, and subtract the boundary layer thickness from the initial capillary radius to obtain a target capillary radius of the single capillary.
In this embodiment, the single-capillary extraction level determination module 200 may be configured to determine the extraction level of oil in the single capillary at a given displacement pressure difference using the following equation:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of the wetting phase in the fluid, Δ p representing the specified displacement pressure difference, σ representing the interfacial tension between the wetting and non-wetting phases in the fluid, and θ representing the contactCorner, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
In this embodiment, the core production degree determining module 300 may be configured to determine the production degree of oil in the capillary bundle at the specified displacement pressure difference by using the following formula:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
Fig. 5 is a schematic diagram of a composition of another embodiment of the apparatus for determining the extent of oil production from a core of the present application. As shown in fig. 5, the apparatus for determining the extent of oil production from a core may include a memory having stored therein a capillary bundle for characterizing the pore structure of the core in a work zone of interest, and initial capillary radius distribution data for the capillary bundle, a processor, and a computer program stored on the memory, the computer program when executed by the processor performing the steps of:
step S101: determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
step S102: determining a degree of production of oil from the single capillary at a specified displacement pressure differential based on the target capillary radius;
step S103: and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
The device embodiment for determining the extraction degree of the oil in the rock core corresponds to the method embodiment for determining the extraction degree of the oil in the rock core, so that the technical scheme of the method embodiment for determining the extraction degree of the oil in the rock core can be realized, and the technical effects of the method embodiment can be obtained.
In the 90 s of the 20 th century, improvements in a technology could clearly distinguish between improvements in hardware (e.g., improvements in circuit structures such as diodes, transistors, switches, etc.) and improvements in software (improvements in process flow). However, as technology advances, many of today's process flow improvements have been seen as direct improvements in hardware circuit architecture. Designers almost always obtain the corresponding hardware circuit structure by programming an improved method flow into the hardware circuit. Thus, it cannot be said that an improvement in the process flow cannot be realized by hardware physical modules. For example, a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), is an integrated circuit whose Logic functions are determined by programming the Device by a user. A digital system is "integrated" on a PLD by the designer's own programming without requiring the chip manufacturer to design and fabricate application-specific integrated circuit chips. Furthermore, nowadays, instead of manually making an Integrated Circuit chip, such Programming is often implemented by "logic compiler" software, which is similar to a software compiler used in program development and writing, but the original code before compiling is also written by a specific Programming Language, which is called Hardware Description Language (HDL), and HDL is not only one but many, such as abel (advanced Boolean Expression Language), ahdl (alternate Language Description Language), traffic, pl (core unified Programming Language), HDCal, JHDL (Java Hardware Description Language), langue, Lola, HDL, laspam, hardbyscript Description Language (vhr Description Language), and the like, which are currently used by Hardware compiler-software (Hardware Description Language-software). It will also be apparent to those skilled in the art that hardware circuitry that implements the logical method flows can be readily obtained by merely slightly programming the method flows into an integrated circuit using the hardware description languages described above.
The controller may be implemented in any suitable manner, for example, the controller may take the form of, for example, a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro) processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, and an embedded microcontroller, examples of which include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320, the memory controller may also be implemented as part of the control logic for the memory.
Those skilled in the art will also appreciate that, in addition to implementing the controller as pure computer readable program code, the same functionality can be implemented by logically programming method steps such that the controller is in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Such a controller may thus be considered a hardware component, and the means included therein for performing the various functions may also be considered as a structure within the hardware component. Or even means for performing the functions may be regarded as being both a software module for performing the method and a structure within a hardware component.
The apparatuses and modules illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions.
For convenience of description, the above devices are described as being divided into various modules by functions, and are described separately. Of course, the functionality of the various modules may be implemented in the same one or more software and/or hardware implementations as the present application.
From the above description of the embodiments, it is clear to those skilled in the art that the present application can be implemented by software plus necessary general hardware platform. With this understanding in mind, the present solution, or portions thereof that contribute to the prior art, may be embodied in the form of a software product, which in a typical configuration includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory. The computer software product may include instructions for causing a computing device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in the various embodiments or portions of embodiments of the present application. The computer software product may be stored in a memory, which may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium. Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include transitory computer readable media (transient media), such as modulated data signals and carrier waves.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The application is operational with numerous general purpose or special purpose computing system environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
The application may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The application may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
While the present application has been described with examples, those of ordinary skill in the art will appreciate that there are numerous variations and permutations of the present application without departing from the spirit of the application, and it is intended that the appended claims encompass such variations and permutations without departing from the spirit of the application.
Claims (10)
1. A method for determining the extraction degree of oil in a rock core is characterized in that a capillary tube bundle for representing the pore structure of the rock core in a target work area and initial capillary radius distribution data of the capillary tube bundle are provided; the method comprises the following steps:
determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
determining a degree of production of oil from the single capillary at a specified displacement pressure differential based on the target capillary radius;
and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
2. The method of claim 1, wherein determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data comprises:
determining a boundary layer thickness at which fluid imbibes in the single capillary at a specified displacement differential pressure;
and acquiring the initial capillary radius of the single capillary from the initial capillary radius distribution data, and subtracting the thickness of the boundary layer from the initial capillary radius to obtain the target capillary radius of the single capillary.
3. The method of claim 2, wherein the boundary layer thickness at which fluid imbibes in the monocapillary at a specified displacement differential pressure is determined using the following equation:
δi＝δ0+r0i·exp(-B·(Δp)-C)
wherein, deltaiRepresents the boundary layer thickness, δ, of the fluid imbibed in the ith single capillary in the capillary bundle0Indicates the thickness of the fluid boundary solidified layer, r0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, Δ p represents the specified displacement pressure differential, B represents a parameter associated with the material of the wall of the single capillary, and C represents a parameter associated with the viscosity of the fluid.
4. The method of claim 1, wherein the extent of oil production in the monocapillary at a given displacement pressure differential is determined using the following equation:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
5. The method of claim 1, wherein the extent of oil production in the capillary bundle at the specified displacement pressure differential is determined using the following equation:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
6. The device for determining the extraction degree of oil in the rock core is characterized by providing a capillary tube bundle for representing the pore structure of the rock core in a target work area and initial capillary radius distribution data of the capillary tube bundle; the device comprises: the device comprises a target radius determining module, a single capillary extraction degree determining module and a rock core extraction degree determining module; wherein the content of the first and second substances,
the target radius determination module is used for determining the target capillary radius of the single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
the single-capillary extraction degree determining module is used for determining the extraction degree of the oil in the single capillary under the specified displacement pressure difference based on the target capillary radius;
and the core extraction degree determining module is used for determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the core.
7. The apparatus of claim 6, wherein the target radius determination module is configured to determine a boundary layer thickness of the fluid imbibed in the single capillary at a specified displacement differential pressure, obtain an initial capillary radius of the single capillary from the initial capillary radius distribution data, and subtract the boundary layer thickness from the initial capillary radius to obtain a target capillary radius of the single capillary.
8. The apparatus of claim 6, wherein the single capillary production determination module is configured to determine the degree of production of oil in the single capillary at a specified displacement pressure differential using the following equation:
wherein R isiRepresents the extent of oil production, μ, in the ith single capillary in the capillary bundle at the specified displacement pressure differentialnwRepresents the viscosity, μ, of a non-wetting phase in said fluidwRepresenting the viscosity of a wetting phase in said fluid, Δ p representing said specified displacement pressure difference, σ representing the interfacial tension between a wetting phase and a non-wetting phase in said fluid, θ representing the contact angle, riRepresents a target capillary radius, L, for an ith single capillary in the capillary bundleTubeRepresents the length of a single capillary in the capillary bundle, and t represents the imbibition time.
9. The apparatus of claim 6, wherein the core production level determination module is configured to determine the production level of oil in the capillary bundle at the specified displacement pressure differential using the following equation:
wherein R isBundlesRepresenting the extent of oil production, R, in the capillary bundle at the specified displacement pressure differenceiRepresenting the extent of oil production in the ith monocapillary tube in the capillary bundle at the specified displacement pressure differential, f (r)0i) Representing the probability density, r, of the ith single capillary in the capillary bundle0iRepresents the initial capillary radius of the ith single capillary in the capillary bundle, N represents the number of capillaries in the capillary bundle, N represents the number of capillaries in the capillary bundle, σ represents the number of capillaries in the capillary bundle0Represents the standard deviation of the initial capillary radii of the n capillaries in the capillary bundle, and ν represents the average of the initial capillary radii of the n capillaries in the capillary bundle.
10. An apparatus for determining the extent of oil production from a core, comprising a memory, a processor, and a computer program stored on the memory, wherein the memory has stored therein a capillary bundle for characterizing the pore structure of the core in a work area of interest, and initial capillary radius distribution data for the capillary bundle, the computer program when executed by the processor performs the steps of:
determining a target capillary radius for a single capillary in the capillary bundle based on the initial capillary radius distribution data; wherein the target capillary radius is used to characterize the radius of the effective flow channel for fluid imbibition in the single capillary at a specified displacement differential pressure;
determining a degree of production of oil from the single capillary at a specified displacement pressure differential based on the target capillary radius;
and determining the extraction degree of the oil in the capillary tube bundle under the specified displacement pressure difference according to the extraction degree of the oil in each single capillary tube in the capillary tube bundle under the specified displacement pressure difference, and taking the extraction degree of the oil in the capillary tube bundle as the extraction degree of the oil in the rock core.
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