An apparatus, method and equipment for measuring the oil saturation of a core after displacement

Abstract

The present application discloses an apparatus, a method and a device for measuring the oil saturation of a core after displacement, which relates to the technical field of oil and gas field development engineering. The apparatus includes: an ultraviolet laser, an ultraviolet spectrometer and a data processing terminal. The ultraviolet laser emits ultraviolet light and irradiates each scanning point on each core slice of the core after displacement respectively. The ultraviolet spectrometer respectively receives the fluorescence reflected by each scanning point on each core slice after being irradiated by the ultraviolet light, and obtains the fluorescence spectral image of each scanning point on each core slice. The data processing terminal respectively processes the fluorescence spectral image of each scanning point on each core slice to obtain the oil saturation of each scanning point on each core slice, so as to determine the oil saturation distribution of the core after displacement. The present application can achieve non-destructive measurement, and has the advantages of simple operation, low cost, short measurement time and high measurement efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field development engineering, and in particular to a device, method and apparatus for measuring the oil saturation of a core after displacement. Background Art

[0002] Core flooding is an experimental technique used to study the flow of fluids, such as oil and gas, within rock pores. A core is placed in a core holder and, using a displacement device, injected with a displacing fluid (such as oil, gas, water, or a chemical displacing agent) to simulate formation conditions, such as temperature, pressure, and fluid velocity. This displacing fluid, such as oil, gas, water, or a chemical displacing agent, is injected into the core, simulating the displacement process used in oil and gas production. Parameters such as pressure, temperature, and flow rate, as well as the core output, are monitored in real time during the displacement process, allowing analysis of the displacement effect and changes in rock properties. Oil saturation is a key parameter for characterizing tight sandstone reservoirs and calculating reserves. It is the ratio of the volume of oil in the reservoir rock's pores to the total pore volume of the rock, expressed as a percentage. Therefore, a technique for characterizing the oil saturation of cores after core flooding experiments is urgently needed.

[0003] For reservoirs characterized by large variations in formation water salinity, complex pore structures, and high shale content, calculating oil saturation in cores after flooding using only resistivity logging data is difficult. In addition to resistivity logging, dielectric logging data is also used to calculate oil saturation in cores after flooding. Currently, in coreflooding experiments, electrical measurements are generally used to obtain dielectric logging data, which is then further analyzed and calculated to determine oil saturation in the core after flooding. However, this requires laying a large number of electrodes, which is complex and difficult to measure in the entire core area after flooding. While CT scanning (Computed Tomography) and nuclear magnetic resonance imaging can achieve non-destructive measurement, they are costly and time-consuming. Summary of the Invention

[0004] The purpose of this application is to provide a device, method and equipment for measuring the oil saturation of cores after displacement, which can realize non-destructive measurement and has simple operation, low cost and high measurement efficiency.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] In a first aspect, the present application provides a method for determining the oil saturation of a core after flooding, the method comprising:

[0007] Obtaining a fluorescence spectrum image of each scanning point on each core slice of the core after displacement; the fluorescence spectrum image is an image generated after the ultraviolet spectrometer receives the fluorescence reflected by the scanning point after being irradiated by ultraviolet light;

[0008] For each fluorescence spectral image of each scanning point on each core slice, perform grayscale processing on the fluorescence spectral image to obtain a grayscale image; calculate the difference between the dark field image and the grayscale image to perform dark field correction on the grayscale image and obtain a dark field corrected grayscale image; perform normalization processing on the dark field corrected grayscale image to obtain a normalized grayscale image; use a pre-established fluorescence intensity - grayscale value calibration equation to process the normalized grayscale image to obtain a corrected fluorescence spectral image; wherein, the dark field image is a fluorescence spectral image obtained by an ultraviolet spectrometer when the ultraviolet laser does not emit ultraviolet light;

[0009] Extract the characteristic parameters of the corrected fluorescence spectral image of each scanning point on each core slice to obtain the characteristic parameters of each scanning point on each core slice; the characteristic parameters include integral intensity and peak wavelength;

[0010] Respectively take the characteristic parameters of each scanning point on each core slice as inputs, and use a pre-established oil saturation calculation model to determine the oil saturation of each scanning point on each core slice;

[0011] Compose the oil saturation of each scanning point on each core slice into the oil saturation distribution of the core after displacement.

[0012] Optionally, the method for establishing the fluorescence intensity - grayscale value calibration equation includes: obtaining the first standard fluorescence spectral image of each scanning point on the first standard core slice; performing grayscale processing on the first standard fluorescence spectral image to obtain a first standard grayscale image; calculating the difference between the dark field image and the first standard grayscale image to perform dark field correction on the first standard grayscale image and obtain a first dark field corrected standard grayscale image; performing normalization processing on the first dark field corrected standard grayscale image to obtain a first normalized standard grayscale image; performing linear fitting on the grayscale values of the first normalized standard grayscale image and the actual fluorescence intensities of the actual fluorescence spectral images corresponding to the first normalized standard grayscale image to obtain the fluorescence intensity - grayscale value calibration equation; wherein, the first normalized standard grayscale image and the actual fluorescence spectral image of the same scanning point on the first standard core slice correspond to each other.

[0013] Optionally, using the pre-established fluorescence intensity - grayscale value calibration equation to process the normalized grayscale image to obtain a corrected fluorescence spectral image specifically includes: for each pixel point of the normalized grayscale image, take the grayscale value of the pixel point as an input, use the pre-established fluorescence intensity - grayscale value calibration equation to calculate the actual fluorescence intensity of the pixel point, and compose the actual fluorescence intensities of all the pixel points into a corrected fluorescence spectral image.

[0014] Optionally, the method for establishing the oil saturation calculation model includes: obtaining the second standard fluorescence spectral image of each scanning point on the second standard core slice; correcting the second standard fluorescence spectral image to obtain a corrected standard fluorescence spectral image; extracting the characteristic parameters of the corrected standard fluorescence spectral image; performing multiple linear regression on the characteristic parameters of the corrected standard fluorescence spectral image and the oil saturation corresponding to the corrected standard fluorescence spectral image to obtain an oil saturation calculation model; wherein, the oil saturation corresponding to the corrected standard fluorescence spectral image is the oil saturation of the scanning points on the second standard core slice corresponding to the corrected standard fluorescence spectral image;

[0015] Among them, correcting the second standard fluorescence spectral image to obtain a corrected standard fluorescence spectral image specifically includes: performing grayscale processing on the second standard fluorescence spectral image to obtain a second standard grayscale image; calculating the difference between the dark field image and the second standard grayscale image to perform dark field correction on the second standard grayscale image to obtain a second dark field corrected standard grayscale image; performing normalization processing on the second dark field corrected standard grayscale image to obtain a second normalized standard grayscale image; using a pre-established fluorescence intensity - grayscale value calibration equation to process the second normalized standard grayscale image to obtain a corrected standard fluorescence spectral image.

[0016] In a second aspect, the present application provides an apparatus for measuring the oil saturation of a core after displacement. The apparatus for measuring the oil saturation of a core after displacement includes: an ultraviolet laser, an ultraviolet spectrometer, and a data processing terminal;

[0017] The ultraviolet laser is used to emit ultraviolet light and irradiate each scanning point on each core slice of the core after displacement; the core slice is a slice obtained by slicing the core after displacement, and the core after displacement is the core after a core displacement experiment;

[0018] The ultraviolet spectrometer is used to respectively receive the fluorescence reflected by each scanning point on each core slice after being irradiated by ultraviolet light to obtain the fluorescence spectral image of each scanning point on each core slice;

[0019] The data processing terminal is communicatively connected to the ultraviolet spectrometer; the data processing terminal is used to execute the above-mentioned method for measuring the oil saturation of the core after displacement to obtain the oil saturation distribution of the core after displacement.

[0020] Optionally, the wavelength range of the ultraviolet light is 315 nm - 400 nm.

[0021] Optionally, the apparatus for measuring the oil saturation of the core after displacement further includes: a stage and a driving component;

[0022] The core slice is located on the stage.

[0023] The driving component is drivingly connected to the stage; the driving component is used to drive the stage to move, so that the ultraviolet light emitted by the ultraviolet laser irradiates each scanning point on the core slice respectively.

[0024] Optionally, the device for measuring the oil saturation of the core after displacement further includes: a dark box, and the ultraviolet laser, the ultraviolet spectrometer, the stage and the driving component are all located inside the dark box.

[0025] Optionally, the device for measuring the oil saturation of the core after displacement further includes: a glass slide and a cover glass. The glass slide is located above the stage, the core slice is located above the glass slide, and the cover glass is located above the core slice.

[0026] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to implement the above method for measuring the oil saturation of the core after displacement.

[0027] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0028] The present application provides a device, a method and equipment for measuring the oil saturation of the core after displacement, including: an ultraviolet laser, an ultraviolet spectrometer and a data processing terminal. The ultraviolet laser emits ultraviolet light and irradiates each scanning point on each core slice of the core after displacement respectively. The ultraviolet spectrometer respectively receives the fluorescence reflected by each scanning point on each core slice after being irradiated by the ultraviolet light, and obtains the fluorescence spectrum image of each scanning point on each core slice. The data processing terminal respectively processes the fluorescence spectrum image of each scanning point on each core slice to obtain the oil saturation of each scanning point on each core slice, and forms the oil saturation distribution of the core after displacement by the oil saturation of each scanning point on each core slice, so as to determine the oil saturation distribution of the core after displacement. The present application only needs to irradiate the core slice with ultraviolet light, and then receive and process the fluorescence spectrum image to complete the measurement of the oil saturation, and can achieve non-destructive measurement. Compared with the electrical measurement method, there is no need to place electrodes in the core slice, and the operation is simple. Compared with CT scanning and nuclear magnetic resonance scanning, there is no need for expensive equipment, the cost is low, and there is no need to perform a large number of scans and calculations on the core after displacement, the measurement time is short, and the measurement efficiency is high. Description of the Drawings

[0029] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an apparatus for measuring the oil saturation of a core after displacement provided in Embodiment 1 of the present application.

[0031] Figure 2 It is a schematic workflow diagram of an apparatus for measuring the oil saturation of a core after displacement provided in Embodiment 1 of the present application.

[0032] Figure 3 It is a schematic flowchart of a method for measuring the oil saturation of a core after displacement provided in Embodiment 2 of the present application.

[0033] Figure 4 It is a schematic structural diagram of a computer device provided in Embodiment 3 of the present application.

[0034] Reference numerals: 1 - ultraviolet laser; 2 - ultraviolet spectrometer; 3 - data processing terminal; 4 - stage; 5 - motor; 6 - receiving light source. Detailed implementation manners

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0036] Embodiment 1.

[0037] This embodiment provides an apparatus for measuring the oil saturation of a core after displacement, as Figure 1 shown. The apparatus for measuring the oil saturation of a core after displacement includes: an ultraviolet laser 1, an ultraviolet spectrometer 2, and a data processing terminal 3.

[0038] The ultraviolet laser 1 is used to emit ultraviolet light and irradiate each scanning point on each core slice of the core after displacement. The core slice is obtained by slicing the core after displacement, and the core after displacement is the core after the core displacement experiment. Specifically, after the core displacement experiment, the core after displacement obtained at this time is acquired, and using a core cutting machine, the core after displacement is cut multiple times along any direction (such as the horizontal direction, vertical direction or inclined direction), so that the core after displacement is cut into multiple thin slices with different positions in the core after displacement and a thickness less than or equal to 3 mm, obtaining multiple core slices. Multiple position points are randomly selected as scanning points on each core slice, obtaining multiple scanning points on each core slice. Subsequently, each scanning point on each core slice is measured to obtain the oil saturation, that is, the determination of the oil saturation of the entire core after displacement is completed.

[0039] The ultraviolet laser 1 can adopt a combined light source of a mercury lamp and a deep ultraviolet LED (Light Emitting Diode), with a power of 50 mW. The wavelength range of the emitted ultraviolet light can be 315 nm - 400 nm, which is suitable for measuring the oil saturation. The ultraviolet laser 1 has an optical power sensor and can adjust the drive current in real time to ensure that the wavelength of the output ultraviolet light is stable within 315 nm - 400 nm, and the wavelength stability is better than ±0.5 nm. The ultraviolet laser 1 can emit ultraviolet light through an optical fiber.

[0040] In order to enable the ultraviolet light emitted by the ultraviolet laser 1 to irradiate each scanning point on each core slice respectively, the oil saturation measurement device for the core after displacement in this embodiment further includes: a stage 4 and a driving component. The core slice is located on the stage 4, and the driving component is drivingly connected to the stage 4. The driving component is used to drive the stage 4 to move, so that the ultraviolet light emitted by the ultraviolet laser 1 irradiates each scanning point on the core slice respectively.

[0041] The stage 4 is a movable stage, and the core slice can be fixed on the stage 4. The driving component can be a motor 5 or an electric motor. At this time, the stage 4 is driven by the motor 5 or the electric motor, and the left - right movement and the front - back movement of the stage 4 can be realized, that is, the movement of the stage 4 on the horizontal plane is realized, so that the core slice carried on the stage 4 completes the scanning process to achieve the full - area scanning of the core slice. Specifically, by driving the stage 4 to move, each scanning point on the core slice moves to directly below the ultraviolet laser 1 respectively. At this time, the ultraviolet light emitted by the ultraviolet laser 1 irradiates this scanning point, so that the ultraviolet light emitted by the ultraviolet laser 1 irradiates each scanning point on the core slice respectively. After completing the scanning of one core slice, replace the core slice on the stage 4 and scan again until each scanning point on each core slice is irradiated respectively. Among them, the stage 4 can be made of a transparent homogeneous material, and the specific material can be transparent quartz glass, ensuring that the incident light can pass through and is not affected by the medium, ensuring that the ultraviolet light transmission is interference - free. The moving accuracy of the stage 4 can be ±10 μm, and the micron - level scanning of the core slice can be realized.

[0042] When fixing the core slice on the stage 4, the core slice can be first fixed on a glass slide made of quartz glass, and then the glass slide is fixed on the stage 4. At this time, the oil - saturation determination device for the core after displacement in this embodiment further includes: a glass slide and a cover glass. The glass slide is located above the stage 4, the core slice is located above the glass slide, and the cover glass is located above the core slice.

[0043] The ultraviolet spectrometer 2 is used to respectively receive the fluorescence reflected by each scanning point on each core slice after being irradiated by ultraviolet light, and obtain the fluorescence spectral image of each scanning point on each core slice. When the ultraviolet light irradiates the scanning point, the fluorescence effect of the oil - containing components at the scanning point will be excited. Specifically, when the oil - containing components are irradiated by ultraviolet light, they will absorb the energy of the ultraviolet light, causing electrons to jump from the ground state to the excited state. Subsequently, during the process of the electrons returning from the excited state to the ground state, energy is released in the form of photons, thereby generating fluorescence. At this time, the ultraviolet spectrometer 2 respectively receives the fluorescence reflected by each scanning point on each core slice after being irradiated by ultraviolet light, and obtains the fluorescence spectral image of each scanning point on each core slice. The fluorescence spectral image uses the wavelength as the abscissa, representing the wavelength range of light, and the fluorescence intensity as the ordinate, representing the intensity of light.

[0044] The ultraviolet spectrometer 2 can have a light - intensity detection interface (specifically, it can be the receiving light source 6). The ultraviolet spectrometer 2 receives the fluorescence generated and reflected after the ultraviolet laser 1 irradiates the core slice through the light - intensity detection interface, and acquires the fluorescence spectral image of each scanning point on each core slice.

[0045] The data processing terminal 3 is communicatively connected to the ultraviolet spectrometer 2. The data processing terminal 3 is used to process the fluorescence spectral images of each scanning point on each core slice to obtain the oil saturation of each scanning point on each core slice, and form the oil saturation distribution of the core after displacement with the oil saturation of each scanning point on each core slice. The algorithm adopted by the data processing terminal 3 can complete the function of converting the fluorescence spectral image received by the ultraviolet spectrometer 2 into oil saturation.

[0046] In this embodiment, a dark box can be used during the scanning process to eliminate the interference of stray light and ensure the accuracy of the fluorescence spectral image. At this time, the oil saturation measuring device for the core after displacement in this embodiment further includes: a dark box, and the ultraviolet laser 1, the ultraviolet spectrometer 2, the stage 4 and the driving component are all located inside the dark box. It should be noted that the dark box refers to a closed box body that is light-tight and completely black inside.

[0047] Based on the oil saturation measuring device for the core after displacement in this embodiment, a working method for the oil saturation measuring device for the core after displacement is further provided, as Figure 2 shown, including the following steps: (1) Place the core slice on the movable stage 4 controlled by the motor 5, and use the ultraviolet laser 1 to emit ultraviolet light and irradiate each scanning point on each core slice respectively to stimulate the fluorescence effect of the oil-containing components at each scanning point on each core slice, so that each scanning point on each core slice reflects fluorescence, that is, based on the ultraviolet-induced fluorescence effect; (2) After being stimulated in step (1), collect the fluorescence reflected by each scanning point on each core slice through the ultraviolet spectrometer 2 to obtain the fluorescence spectral image of each scanning point on each core slice; (3) Perform digital processing on the fluorescence spectral image, extract the characteristic parameters representing the fluorescence intensity distribution in the fluorescence spectral image, and calculate the oil saturation of each scanning point on each core slice based on the preset corresponding relationship model between the characteristic parameters and the oil saturation (that is, the pre-established oil saturation calculation model).

[0048] At this time, the method for measuring the oil saturation of the core after displacement includes: obtaining the fluorescence spectral image of each scanning point on each core slice of the core after displacement; respectively correcting the fluorescence spectral image of each scanning point on each core slice to obtain the corrected fluorescence spectral image of each scanning point on each core slice; extracting the characteristic parameters of the corrected fluorescence spectral image of each scanning point on each core slice to obtain the characteristic parameters of each scanning point on each core slice, and the characteristic parameters include integral intensity and peak wavelength; respectively using the characteristic parameters of each scanning point on each core slice as inputs, and using the pre-established oil saturation calculation model to determine the oil saturation of each scanning point on each core slice; and composing the oil saturations of each scanning point on each core slice into the oil saturation distribution of the core after displacement.

[0049] Considering that there are errors in the fluorescence intensity in the fluorescence spectral image directly collected by the ultraviolet spectrometer 2, in this embodiment, a correction process of the fluorescence spectral image is introduced. The fluorescence spectral image is grayscale processed to convert the original fluorescence spectral image into a grayscale image. The grayscale image can accurately show the level of oil content at different positions of the core slice. At the position with more oil, the gray color will be deeper. After the dark field correction and normalization processing of the grayscale image, the actual fluorescence intensity is calculated according to the fluorescence intensity-grayscale value calibration equation to obtain the corrected fluorescence spectral image, and the correction of the fluorescence spectral image is completed. Specifically, the dark field image under the condition of no light is subtracted from the grayscale image, that is, the gray value of each pixel point of the dark field image is subtracted from the corresponding pixel point of the grayscale image to eliminate the sensor noise, and the dark field correction of the grayscale image is performed to obtain the grayscale image after dark field correction. The grayscale image after dark field correction is normalized, that is, the gray value of each pixel point of the grayscale image after dark field correction is normalized to the range of [0, 1] to enhance the stability of the data and obtain the normalized grayscale image. The pre-established fluorescence intensity-grayscale value calibration equation is used to process the normalized grayscale image to obtain the corrected fluorescence spectral image. At this time, the fluorescence intensity of each pixel point of the obtained corrected fluorescence spectral image is more consistent with the actual fluorescence intensity, thereby reducing the error in the fluorescence spectral image, and the oil saturation can be calculated more accurately subsequently.

[0050] Among them, the fluorescence intensity-grayscale value calibration equation is established by using the first standard core slice with known actual fluorescence intensity, that is, the quantitative mapping relationship between the grayscale value and the actual fluorescence intensity is established. The expression of the fluorescence intensity-grayscale value calibration equation is actual fluorescence intensity = K × grayscale value + b. Specifically, the actual fluorescence intensity of the actual fluorescence spectral image of each scanning point on the first standard core slice is used as the ordinate, and the grayscale value of the first normalized standard grayscale image of the same scanning point on the first standard core slice is used as the abscissa for linear regression fitting to determine the conversion coefficient K and the intercept b.

[0051] At this time, in this embodiment, the fluorescence spectral images of each scanning point on each core slice are corrected respectively to obtain the corrected fluorescence spectral images of each scanning point on each core slice, which specifically includes: for the fluorescence spectral image of each scanning point on each core slice, performing grayscale processing on the fluorescence spectral image to obtain a grayscale image; calculating the difference between the dark-field image and the grayscale image to perform dark-field correction on the grayscale image to obtain a dark-field corrected grayscale image; performing normalization processing on the dark-field corrected grayscale image to obtain a normalized grayscale image; using the pre-established fluorescence intensity-grayscale value calibration equation to process the normalized grayscale image to obtain the corrected fluorescence spectral image. Among them, the dark-field image is the fluorescence spectral image obtained by the ultraviolet spectrometer 2 when the ultraviolet laser 1 does not emit ultraviolet light.

[0052] Among them, the method for establishing the fluorescence intensity-grayscale value calibration equation includes: obtaining the first standard fluorescence spectral image of each scanning point on the first standard core slice; performing grayscale processing on the first standard fluorescence spectral image to obtain the first standard grayscale image; calculating the difference between the dark-field image and the first standard grayscale image to perform dark-field correction on the first standard grayscale image to obtain the first dark-field corrected standard grayscale image; performing normalization processing on the first dark-field corrected standard grayscale image to obtain the first normalized standard grayscale image; performing linear fitting on the grayscale value of the first normalized standard grayscale image and the actual fluorescence intensity of the actual fluorescence spectral image corresponding to the first normalized standard grayscale image to obtain the fluorescence intensity-grayscale value calibration equation. Among them, the first normalized standard grayscale image and the actual fluorescence spectral image of the same scanning point on the first standard core slice correspond to each other. The independent variable of the fluorescence intensity-grayscale value calibration equation is the grayscale value, and the dependent variable is the actual fluorescence intensity. When performing linear fitting, when the abscissa takes the grayscale value of a certain pixel point in the first normalized standard grayscale image, the ordinate correspondingly takes the actual fluorescence intensity of the corresponding pixel point in the actual fluorescence spectral image corresponding to the first normalized standard grayscale image.

[0053] At this time, using the pre-established fluorescence intensity-grayscale value calibration equation to process the normalized grayscale image to obtain the corrected fluorescence spectral image specifically includes: for each pixel point of the normalized grayscale image, using the grayscale value of the pixel point as the input, and using the pre-established fluorescence intensity-grayscale value calibration equation to calculate the actual fluorescence intensity of the pixel point, and forming the corrected fluorescence spectral image with the actual fluorescence intensities of all pixel points.

[0054] In this embodiment, multiple second standard core slices with known oil saturation are prepared, and an oil saturation calculation model is established through the second standard core slices. Specifically, multiple linear regression analysis is performed on the characteristic parameters and oil saturation. Specifically, more than five groups of second standard core slices with known oil saturation are prepared by indoor experimental methods, and characteristic parameters such as the integrated intensity and peak wavelength of the corrected standard fluorescence spectral image of each scanning point on the second standard core slice are extracted. The integrated intensity refers to the area between the spectral curve and the horizontal axis (wavelength axis), which synthesizes the light intensity information of all wavelengths within the spectral range and reflects the total radiation energy of the light source in a certain wavelength band. The peak wavelength is the wavelength corresponding to the point with the maximum light intensity in the spectrum, that is, the wavelength corresponding to the highest point of the spectral curve, which indicates the wavelength position of the part with the maximum intensity in the light emitted by the light source. Then, multiple linear regression is performed on the characteristic parameters and oil saturation to establish a multiple linear regression equation between the characteristic parameters and oil saturation, and the oil saturation calculation model can be obtained: So = aI + bλmax + c, where So is the oil saturation, I is the integrated intensity, λmax is the peak wavelength, and a, b, and c are all regression coefficients.

[0055] At this time, in this embodiment, the method for establishing the oil saturation calculation model includes: obtaining the second standard fluorescence spectral image of each scanning point on the second standard core slice; correcting the second standard fluorescence spectral image to obtain the corrected standard fluorescence spectral image; extracting the characteristic parameters of the corrected standard fluorescence spectral image; performing multiple linear regression on the characteristic parameters of the corrected standard fluorescence spectral image and the oil saturation corresponding to the corrected standard fluorescence spectral image to obtain the oil saturation calculation model. Among them, the oil saturation corresponding to the corrected standard fluorescence spectral image is the oil saturation of the scanning point on the second standard core slice corresponding to the corrected standard fluorescence spectral image. The independent variable of the oil saturation calculation model is the characteristic parameter, and the dependent variable is the oil saturation.

[0056] Among them, correcting the second standard fluorescence spectral image to obtain the corrected standard fluorescence spectral image specifically includes: performing grayscale processing on the second standard fluorescence spectral image to obtain the second standard grayscale image; calculating the difference between the dark field image and the second standard grayscale image to perform dark field correction on the second standard grayscale image to obtain the second dark field corrected standard grayscale image; performing normalization processing on the second dark field corrected standard grayscale image to obtain the second normalized standard grayscale image; using the pre-established fluorescence intensity - grayscale value calibration equation to process the second normalized standard grayscale image to obtain the corrected standard fluorescence spectral image.

[0057] This embodiment discloses an apparatus for measuring the oil saturation of a core after displacement. An ultraviolet laser 1 is used to emit ultraviolet light with a wavelength of 315 nm - 400 nm to irradiate the core slice. A movable stage 4 controlled by a motor 5 is used to locate the scanning points of the core slice and perform a full-area scan. An ultraviolet spectrometer 2 is used to receive the reflected fluorescence and obtain a fluorescence spectral image, so as to obtain the fluorescence spectral images of all scanning points on each core slice. Based on the quantitative relationship between the characteristic parameters of the fluorescence spectral image and the oil saturation, the calculation of the oil saturation is realized.

[0058] In this embodiment, the fluorescence intensity - gray value calibration equation and the oil saturation calculation model can be established simultaneously through the same standard core slices, which specifically may include the following steps.

[0059] (1)Select a displaced core with a diameter of 2.5 cm, cut it using a core cutter, cut the displaced core into core slices with a thickness of 3 mm, fix the core slices on a glass slide, and ensure they are flat and free of bubbles.

[0060] (2)Prepare five groups of standard core slices with known oil saturations (0%, 20%, 40%, 60%, 80%). Specifically, inject different proportions of simulated crude oil and formation water into the core slices through the vacuum saturation method to ensure uniform distribution, and obtain the standard core slices.

[0061] (3)Place the standard core slices on the stage 4 and adjust the scanning points of the standard core slices through the stage 4.

[0062] (4)Start the ultraviolet laser 1 and perform a full-area scan of the standard core slices, and gradually excite the oil components in the standard core slices to produce fluorescence, so that each scanning point on the standard core slice reflects fluorescence.

[0063] (5)The ultraviolet spectrometer 2 receives the reflected fluorescence through an optical fiber, collects the standard fluorescence spectral images of each scanning point, and keep the ambient light shielded during the scanning process to avoid interference from stray light.

[0064] (6)Convert the standard fluorescence spectral image into a standard gray image, subtract the standard gray image from the dark-field image under the condition of no light illumination to eliminate the sensor noise, obtain the standard gray image after dark-field correction, perform normalization processing on the gray value of each pixel point of the standard gray image after dark-field correction, normalize the gray value to the range of [0, 1] to enhance the data stability, obtain the normalized standard gray image. Take the actual fluorescence intensity of the standard core slice as the ordinate and the gray value after graying, dark-field correction and normalization processing as the abscissa, perform linear regression fitting, and obtain the fluorescence intensity - gray value calibration equation.

[0065] (7) Process the normalized standard grayscale image using the fluorescence intensity - grayscale value calibration equation to obtain the corrected standard fluorescence spectral image. Conduct a multiple linear regression analysis on the characteristic parameters of the corrected standard fluorescence spectral image of the standard core slice and the oil saturation to obtain the oil saturation calculation model.

[0066] Next, the oil saturation measurement device for the core after displacement in this embodiment will be further introduced through two examples.

[0067] Example 1.

[0068] In this example, a betaine solution with a concentration of 0.3% was selected for an indoor core displacement experiment, and the oil saturation of the remaining oil in the core after displacement was roughly calculated to be 20.15%.

[0069] (1) Use a core cutter to cut the core after displacement. The length of the obtained core slice is 1.5 cm, the width is 1 cm, and the thickness is 3 mm.

[0070] (2) Fix the core slice on a glass slide and ensure that there are no bubbles in the glass slide. Place the glass slide on the stage 4 and start the ultraviolet laser 1 to irradiate a certain scanning point on the core slice with ultraviolet light.

[0071] (3) Receive the fluorescence reflected by a certain scanning point on the core slice through the light intensity detection interface, input it into the ultraviolet spectrometer 2 via an optical fiber, and record the fluorescence spectral image of this micro - area of the scanning point.

[0072] (4) Move the core slice through the stage 4 to move it to the next scanning point, irradiate the next scanning point, and record the fluorescence spectral image of the next scanning point until all scanning points are measured, obtaining the fluorescence spectral images of each scanning point on the core slice.

[0073] (5) Replace the core slice on the stage 4 and return to step (2) until the fluorescence spectral images of each scanning point on each core slice are obtained.

[0074] (6) For the fluorescence spectral image of each scanning point on each core slice, correct the fluorescence spectral image through grayscale processing, dark - field correction, and normalization processing to obtain the corrected fluorescence spectral image. Then extract the characteristic parameters of the corrected fluorescence spectral image, calculate the oil saturation based on the characteristic parameters, obtain the oil saturation of each scanning point on each core slice, and thus can obtain the oil saturation values of the core slices taken at different core positions. According to the oil saturation values of the core slices taken at different core positions, the oil saturation distribution of the entire core after displacement can be reconstructed, and finally the oil saturation value of the entire core after displacement is calculated to be 20.21%.

[0075] Example 2

[0076] In this example, a weak base ternary system solution with a concentration of 0.3% was selected for an indoor core displacement experiment. After rough calculation, the oil saturation of the remaining oil in the core after displacement was 18.46%.

[0077] (1) The displaced core was cut using a core cutter. The length of the obtained core slice was 1.5 cm, the width was 1 cm, and the thickness was 3 mm.

[0078] (2) The core slice was fixed on a glass slide, and it was ensured that there were no bubbles in the glass slide. The glass slide was placed on the stage 4, and the ultraviolet laser 1 was started to irradiate a certain scanning point on the core slice with ultraviolet light.

[0079] (3) The fluorescence reflected by a certain scanning point on the core slice was received through the light intensity detection interface, input into the ultraviolet spectrometer 2 via an optical fiber, and the fluorescence spectral image of this micro-region of the scanning point was recorded.

[0080] (4) The movement of the core slice was achieved through the stage 4 to move it to the next scanning point, irradiate the next scanning point, record the fluorescence spectral image of the next scanning point, until the measurement of all scanning points was completed, and the fluorescence spectral images of each scanning point on the core slice were obtained.

[0081] (5) The core slice on the stage 4 was replaced, and the process returned to step (2) until the fluorescence spectral images of each scanning point on each core slice were obtained.

[0082] (6) For the fluorescence spectral images of each scanning point on each core slice, the fluorescence spectral images were corrected through grayscale processing, dark field correction, and normalization processing to obtain the corrected fluorescence spectral images. Then, the characteristic parameters of the corrected fluorescence spectral images were extracted, and the oil saturation was calculated based on the characteristic parameters to obtain the oil saturation of each scanning point on each core slice. Therefore, the oil saturation values of the core slices taken at different core positions can be obtained. Based on the oil saturation values of the core slices taken at different core positions, the oil saturation distribution of the entire displaced core can be reconstructed, and finally, the oil saturation value of the entire displaced core was calculated to be 18.22%.

[0083] In addition to the disadvantages of high cost and long measurement time, CT scans and nuclear magnetic resonance scans have limited resolution for low oil saturation regions. There is an urgent need to develop an oil saturation measurement scheme that combines non-destructiveness, low cost, high precision, and high efficiency. This embodiment specifically provides an oil saturation measurement device for core samples after displacement based on ultraviolet spectral imaging. Through the quantitative mapping relationship between the actual fluorescence intensity and the gray value, the accurate calculation of oil saturation is achieved. The core is to utilize the physical phenomenon that oil-containing components produce characteristic fluorescence under ultraviolet light excitation, extract characteristic parameters through digital processing of the fluorescence spectral image, and further convert the characteristic parameters into oil saturation. Through ultraviolet spectral imaging technology, the cost is reduced while ensuring accuracy, and it is suitable for rapid on-site detection.

[0084] Compared with the prior art, the beneficial effects of this embodiment are as follows: First, it is a non-destructive detection that maintains the integrity of the core; second, it realizes the scanning of all micro-regions of the core slice to obtain the fluorescence spectral image of the entire region of the core slice; third, through digital processing, the fluorescence spectral image of the core slice obtained by the ultraviolet spectrometer 2 is converted into oil saturation, realizing the quantification of oil saturation. Moreover, in the quantification process, the relationship between the gray value - actual fluorescence intensity - oil saturation is established, which can remove errors and improve the measurement accuracy.

[0085] Embodiment 2.

[0086] This embodiment provides an oil saturation measurement method for core samples after displacement, which is applied to the oil saturation measurement device for core samples after displacement described in Embodiment 1. As Figure 3 1 shown, the oil saturation measurement method for core samples after displacement includes the following steps.

[0087] S1: Obtain the fluorescence spectral image of each scanning point on each core slice of the core sample after displacement.

[0088] S2: Respectively correct the fluorescence spectral image of each scanning point on each core slice to obtain the corrected fluorescence spectral image of each scanning point on each core slice.

[0089] S3: Extract the characteristic parameters of the corrected fluorescence spectral image of each scanning point on each core slice to obtain the characteristic parameters of each scanning point on each core slice; the characteristic parameters include integral intensity and peak wavelength.

[0090] S4: Respectively use the characteristic parameters of each scanning point on each core slice as inputs, and utilize the pre-established oil saturation calculation model to determine the oil saturation of each scanning point on each core slice.

[0091] S5: The oil saturations of each scanning point on each core slice form the oil saturation distribution of the core sample after displacement.

[0092] In S2, the fluorescence spectral images of each scanning point on each core slice are corrected respectively to obtain the corrected fluorescence spectral images of each scanning point on each core slice, which specifically includes: for the fluorescence spectral image of each scanning point on each core slice, performing grayscale processing on the fluorescence spectral image to obtain a grayscale image; calculating the difference between the dark field image and the grayscale image to perform dark field correction on the grayscale image and obtain a dark field corrected grayscale image; performing normalization processing on the dark field corrected grayscale image to obtain a normalized grayscale image; using a pre-established fluorescence intensity-grayscale value calibration equation to process the normalized grayscale image to obtain a corrected fluorescence spectral image, where the dark field image is the fluorescence spectral image obtained by the ultraviolet spectrometer when the ultraviolet laser does not emit ultraviolet light.

[0093] Among them, the method for establishing the fluorescence intensity-grayscale value calibration equation includes: obtaining the first standard fluorescence spectral images of each scanning point on the first standard core slice; performing grayscale processing on the first standard fluorescence spectral images to obtain the first standard grayscale images; calculating the difference between the dark field image and the first standard grayscale images to perform dark field correction on the first standard grayscale images and obtain the first dark field corrected standard grayscale images; performing normalization processing on the first dark field corrected standard grayscale images to obtain the first normalized standard grayscale images; performing linear fitting on the grayscale values of the first normalized standard grayscale images and the actual fluorescence intensities of the actual fluorescence spectral images corresponding to the first normalized standard grayscale images to obtain the fluorescence intensity-grayscale value calibration equation, where the first normalized standard grayscale image and the actual fluorescence spectral image of the same scanning point on the first standard core slice correspond to each other.

[0094] At this time, using the pre-established fluorescence intensity-grayscale value calibration equation to process the normalized grayscale image to obtain a corrected fluorescence spectral image, which specifically includes: for each pixel point of the normalized grayscale image, using the grayscale value of the pixel point as the input, calculating the actual fluorescence intensity of the pixel point by using the pre-established fluorescence intensity-grayscale value calibration equation, and forming the corrected fluorescence spectral image with the actual fluorescence intensities of all pixel points.

[0095] Among them, the method for establishing an oil saturation calculation model includes: obtaining the second standard fluorescence spectral image of each scanning point on the second standard core slice; correcting the second standard fluorescence spectral image to obtain a corrected standard fluorescence spectral image; extracting the characteristic parameters of the corrected standard fluorescence spectral image; performing multiple linear regression on the characteristic parameters of the corrected standard fluorescence spectral image and the oil saturation corresponding to the corrected standard fluorescence spectral image to obtain an oil saturation calculation model, where the oil saturation corresponding to the corrected standard fluorescence spectral image is the oil saturation of the scanning points on the second standard core slice corresponding to the corrected standard fluorescence spectral image.

[0096] Among them, correcting the second standard fluorescence spectral image to obtain a corrected standard fluorescence spectral image specifically includes: performing grayscale processing on the second standard fluorescence spectral image to obtain a second standard grayscale image; calculating the difference between the dark field image and the second standard grayscale image to perform dark field correction on the second standard grayscale image to obtain a second dark field-corrected standard grayscale image; performing normalization processing on the second dark field-corrected standard grayscale image to obtain a second normalized standard grayscale image; using a pre-established fluorescence intensity-gray value calibration equation to process the second normalized standard grayscale image to obtain a corrected standard fluorescence spectral image.

[0097] Example 3.

[0098] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 4 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for determining the oil saturation of a core after displacement.

[0099] Those skilled in the art can understand, Figure 4The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0100] In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the oil saturation determination method of the core after displacement in Embodiment 2 is implemented.

[0101] Embodiment 4.

[0102] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the oil saturation determination method of the core after displacement in Embodiment 2 is implemented.

[0103] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0104] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0105] Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, based on the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation on this application.

Claims

1. A method for determining oil saturation of a core after flooding, characterized in that: The method for determining the oil saturation of the core after displacement includes: Obtaining a fluorescence spectrum image of each scanning point on each core slice of the core after displacement; the fluorescence spectrum image is an image generated after the ultraviolet spectrometer receives the fluorescence reflected by the scanning point after being irradiated by ultraviolet light; For each scanning point on each core slice, the fluorescence spectrum image is gray-scaled to obtain a grayscale image; the difference between the dark field image and the grayscale image is calculated to perform dark field correction on the grayscale image to obtain a dark field corrected grayscale image; the dark field corrected grayscale image is normalized to obtain a normalized grayscale image; the normalized grayscale image is processed using a pre-established fluorescence intensity-grayscale value calibration equation to obtain a corrected fluorescence spectrum image; wherein the dark field image is a fluorescence spectrum image obtained by an ultraviolet spectrometer when the ultraviolet laser does not emit ultraviolet light; Extracting characteristic parameters of the corrected fluorescence spectrum image of each scanning point on each core slice to obtain characteristic parameters of each scanning point on each core slice; the characteristic parameters include integrated intensity and peak wavelength; The characteristic parameters of each scanning point on each core slice are used as input, and the oil saturation of each scanning point on each core slice is determined using a pre-established oil saturation calculation model; The oil saturation of each scan point on each core slice is combined into the oil saturation distribution of the core after displacement; The method for establishing the oil saturation calculation model includes: obtaining a second standard fluorescence spectrum image for each scanning point on a second standard core slice; correcting the second standard fluorescence spectrum image to obtain a corrected standard fluorescence spectrum image; extracting characteristic parameters of the corrected standard fluorescence spectrum image; performing multivariate linear regression on the characteristic parameters of the corrected standard fluorescence spectrum image and the oil saturation corresponding to the corrected standard fluorescence spectrum image to obtain an oil saturation calculation model; wherein the oil saturation corresponding to the corrected standard fluorescence spectrum image is the oil saturation of the scanning point on the second standard core slice corresponding to the corrected standard fluorescence spectrum image; Among them, correcting the second standard fluorescence spectral image to obtain a corrected standard fluorescence spectral image specifically includes: grayscale processing the second standard fluorescence spectral image to obtain a second standard grayscale image; calculating the difference between the dark field image and the second standard grayscale image to perform dark field correction on the second standard grayscale image to obtain a second dark field corrected standard grayscale image; normalizing the second dark field corrected standard grayscale image to obtain a second normalized standard grayscale image; and processing the second normalized standard grayscale image using a pre-established fluorescence intensity-grayscale value calibration equation to obtain a corrected standard fluorescence spectral image.

2. The method for determining oil saturation of a core after displacement according to claim 1, characterized in that: The method for establishing the fluorescence intensity-grayscale value calibration equation includes: obtaining a first standard fluorescence spectrum image of each scanning point on a first standard core slice; gray-scaling the first standard fluorescence spectrum image to obtain a first standard grayscale image; calculating the difference between a dark field image and the first standard grayscale image to perform dark field correction on the first standard grayscale image to obtain a first dark field corrected standard grayscale image; normalizing the first dark field corrected standard grayscale image to obtain a first normalized standard grayscale image; linearly fitting the grayscale value of the first normalized standard grayscale image and the actual fluorescence intensity of the actual fluorescence spectrum image corresponding to the first normalized standard grayscale image to obtain a fluorescence intensity-grayscale value calibration equation; wherein, the first normalized standard grayscale image and the actual fluorescence spectrum image of the same scanning point on the first standard core slice correspond to each other.

3. The method for determining oil saturation of a core after flooding according to claim 2, wherein: The normalized grayscale image is processed using a pre-established fluorescence intensity-grayscale value calibration equation to obtain a corrected fluorescence spectrum image, specifically comprising: for each pixel point of the normalized grayscale image, using the grayscale value of the pixel point as input, using the pre-established fluorescence intensity-grayscale value calibration equation to calculate the actual fluorescence intensity of the pixel point, and forming the actual fluorescence intensities of all the pixel points into a corrected fluorescence spectrum image.

4. A device for measuring oil saturation of cores after displacement, characterized in that: The device for measuring oil saturation of the core after displacement includes: an ultraviolet laser, an ultraviolet spectrometer and a data processing terminal; The ultraviolet laser is used to emit ultraviolet light and illuminate each scanning point on each core slice of the core after displacement, respectively; the core slice is a slice obtained by slicing the core after displacement, and the core after displacement is a core after a core displacement experiment; The ultraviolet spectrometer is used to respectively receive the fluorescence reflected by each scanning point on each core slice after being irradiated by ultraviolet light, and obtain a fluorescence spectrum image of each scanning point on each core slice; The data processing terminal is communicatively connected to the ultraviolet spectrometer; the data processing terminal is used to execute the method for determining the oil saturation of the core after displacement according to any one of claims 1 to 3 to obtain the oil saturation distribution of the core after displacement.

5. The device for measuring oil saturation of a core after displacement according to claim 4, characterized in that: The wavelength range of the ultraviolet light is 315 nm-400 nm.

6. The device for measuring oil saturation of a core after displacement according to claim 4, characterized in that: The device for measuring oil saturation of cores after displacement further comprises: a stage and a driving component; The core slice is located on the stage; The driving component is connected to the stage in a driving manner; the driving component is used to drive the stage to move so that the ultraviolet light emitted by the ultraviolet laser illuminates each scanning point on the core slice respectively.

7. The device for measuring oil saturation of a core after displacement according to claim 6, characterized in that: The device for measuring the oil saturation of the core after displacement further includes a dark box, in which the ultraviolet laser, the ultraviolet spectrometer, the stage and the driving component are all located.

8. The device for measuring oil saturation of a core after displacement according to claim 6, characterized in that: The device for determining the oil saturation of the core after displacement further includes: a glass slide and a cover glass. The glass slide is located above the stage, the core slice is located above the glass slide, and the cover glass is located above the core slice.

9. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for determining oil saturation of a core after displacement according to any one of claims 1 to 3.

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