Methods, apparatuses, media, and devices for determining supercritical co2 content in a reservoir

Abstract

The application provides a method, device, medium and equipment for determining the content of supercritical CO2 in an oil reservoir, comprising the following steps: determining the neutron porosity and density porosity in the whole well section of the oil reservoir based on the normalized old well logging data; fitting a first curve based on the normal neutron porosity and density porosity; determining the volume content of supercritical carbon dioxide contained in the oil well, and fitting a second curve based on the slope value corresponding to each first curve and the volume content of supercritical carbon dioxide in the corresponding oil well; and determining the volume content of supercritical carbon dioxide in the explored oil field according to the second curve; thus, since the influence of supercritical carbon dioxide with different contents on the neutron porosity and density porosity is different, the slope corresponding to the first curve and the volume content of supercritical carbon dioxide are twice fitted, so that the relationship between the neutron porosity, the density porosity and the volume content of supercritical carbon dioxide can be accurately reflected, and the oil reservoir productivity can be accurately predicted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas development, and particularly relates to a method, device, medium and equipment for determining the content of supercritical CO2 in an oil reservoir. BACKGROUND

[0002] The subsalt carbonate rock series in a certain basin in Brazil is a hot spot for global oil and gas exploration in recent years, but the discovered oil and gas fields in the subsalt all contain carbon dioxide CO2 to varying degrees, which not only directly reduces the content of hydrocarbon fluids in the oil and gas reservoir and the economic benefits of exploration, but also brings many difficulties and challenges to oil and gas exploration and development and production.

[0003] The calculation of the volume content of supercritical carbon dioxide is one of the key technologies for the deepwater lacustrine carbonate rock oil and gas exploration and development in the basin. However, the content of supercritical carbon dioxide in the oil reservoir cannot be accurately measured before exploitation in the prior art, which leads to the inability to accurately predict the production capacity of the oil reservoir. SUMMARY

[0004] In view of the problems in the prior art, the embodiments of the present application provide a method, device, medium and equipment for determining the content of supercritical CO2 in an oil reservoir, to solve or partially solve the technical problem that the content of supercritical carbon dioxide in the oil reservoir cannot be accurately determined before oil and gas exploration and development in the prior art, which leads to the inability to predict the production capacity of the oil reservoir, and further leads to the inability to ensure the stability of the production rate.

[0005] In a first aspect, the present application provides a method for determining the content of supercritical CO2 in an oil reservoir, characterized in that the method comprises:

[0006] standardizing the well logging data of old wells in the exploration oil field, determining the neutron porosity and the density porosity of the whole well section of the oil reservoir based on the standardized well logging data of the old wells; when the content of supercritical CO2 at each depth in the whole well section is different, the corresponding neutron porosity and the corresponding density porosity are also different;

[0007] removing the abnormal neutron porosity and the abnormal density porosity in the oil layer to obtain normal neutron porosity and normal density porosity;

[0008] for each oil well, fitting a first curve based on the normal neutron porosity and the normal density porosity, determining the slope value corresponding to each first curve, and determining the volume content of supercritical carbon dioxide contained in the oil well;

[0009] fitting a second curve based on the slope value corresponding to each first curve and the volume content of supercritical carbon dioxide in the corresponding oil well;

[0010] determining the volume content of supercritical carbon dioxide in a new well of the exploration oil field according to the second curve.

[0011] In the above scheme, the standardization processing of logging data from multiple oil wells in the exploration oilfield includes:

[0012] Obtain reference density data and reference neutron data corresponding to the reservoir marker layer of the standard well; the reservoir marker layer includes mudstone layer, salt rock layer or gypsum layer;

[0013] Obtain the current density data and current neutron data of the reservoir marker layer from the logging data of the old well; determine the density data calibration amount based on the reference density data and the current density data; and determine the neutron data calibration amount based on the reference neutron data and the current neutron data.

[0014] The density data of the remaining segments in the logging data of the old well are calibrated based on the density data calibration amount, and the neutron data of the remaining segments in the logging data of the old well are calibrated based on the neutron data calibration amount.

[0015] In the above scheme, determining the neutron porosity of the entire reservoir section based on standardized old well logging data includes:

[0016] According to the formula Determine the formation clay content V SH ;

[0017] To obtain the neutron porosity in pure mudstone layers from old well logging data, according to the formula Φ N =Φ log -V SH *Φ Nsh Determine the neutron porosity Φ in the remaining segments N ;in,

[0018] SH is the clay content index, GCUR is a regional empirical constant, and Φ is... log The neutron value for the entire well section, Φ Nsh The neutron porosity is the value of the pure mudstone layer in the logging data of the old well.

[0019] In the above scheme, determining the density and porosity of the entire reservoir section based on standardized old well logging data includes:

[0020] According to the formula Determine the density porosity Φ of the entire well section of the reservoir. D ;in,

[0021] ρ b ρ is the formation density value in the logging data of the old well. ma The ρ is the skeleton density value in the logging data of the old well. f The fluid density value in the logging data of the old well, the ρ sha pure mudstone density value in the well logging data of the old well, the V SH a formation shale content in the well logging data of the old well.

[0022] In the above scheme, the method further comprises:

[0023] determining a shale index SH according to the formula determining a shale index SH; wherein,

[0024] the GR is a true natural gamma value of a current interval in the well logging data of the old well, the GR max a preset maximum natural gamma value, the GR min a preset minimum natural gamma value.

[0025] In the above scheme, the fitting of the first curve based on the normal neutron porosity and the density porosity comprises:

[0026] For each oil well, a linear fitting is performed on the normal neutron porosity and the density porosity based on a preset curve fitting function to obtain a first curve; the first curve has a linear characteristic.

[0027] In the above scheme, the fitting of the second curve based on the slope value corresponding to each first curve and the supercritical carbon dioxide volume content in the corresponding oil well comprises:

[0028] A linear fitting is performed on the slope value corresponding to each first curve and the supercritical carbon dioxide volume content in the corresponding oil well based on a preset curve fitting function to obtain a second curve, and the function corresponding to the second curve is: wherein,

[0029] the a supercritical carbon dioxide volume content, the k is a slope of the second curve, the n is a constant, and the m is a constant.

[0030] In a second aspect of the present application, a device for determining the supercritical CO2 content in an oil reservoir is provided, and the device comprises:

[0031] a data processing unit configured to perform standardization processing on the well logging data of a plurality of oil wells in an oil field under exploration, determine the neutron porosity and the density porosity in the whole well interval of the oil reservoir based on the well logging data after standardization, and when the supercritical CO2 content in the whole well interval is different, the corresponding neutron porosity and the density porosity are also different; and the abnormal neutron porosity and the density porosity are removed to obtain the normal neutron porosity and the density porosity.

[0032] The first fitting unit is configured to, for each oil well, fit a first curve based on the normal neutron porosity and the density porosity, determine a slope value corresponding to each of the first curves, and determine a volume content of supercritical carbon dioxide contained in the oil well;

[0033] The second fitting unit is configured to fit a second curve based on the slope value corresponding to each of the first curves and the volume content of supercritical carbon dioxide in the corresponding oil well.

[0034] The determining unit is configured to determine the volume content of supercritical carbon dioxide in a new well of the exploration oilfield according to the second curve.

[0035] In a third aspect, the present application provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of any of the methods of the first aspect.

[0036] In a fourth aspect, the present application provides a computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of any of the methods of the first aspect when executing the program.

[0037] The present application provides a method, device, medium and equipment for determining the content of supercritical CO2 in an oil reservoir. The method comprises: standardizing the logging data of old wells in a plurality of oil wells of an exploration oilfield, determining the neutron porosity and the density porosity of the whole well section of the oil reservoir based on the standardized logging data of the old wells, determining the volume content of supercritical CO2 in the whole well section, and determining that the corresponding neutron porosity and density porosity are different when the content of supercritical CO2 in the whole well section is different; removing abnormal neutron porosity and density porosity in the oil layer to obtain normal neutron porosity and density porosity; fitting a first curve based on the normal neutron porosity and the density porosity for each oil well, determining a slope value corresponding to each of the first curves, determining the volume content of supercritical carbon dioxide contained in the oil well, fitting a second curve based on the slope value corresponding to each of the first curves and the volume content of supercritical carbon dioxide in the corresponding oil well, and determining the volume content of supercritical carbon dioxide in a new well of the exploration oilfield according to the second curve. Thus, since the effects of supercritical carbon dioxide with different contents on neutron porosity and density porosity are different, the present application performs curve fitting on the corresponding relationship between the fitting curves of neutron porosity and density porosity and the content of supercritical carbon dioxide, and further performs secondary fitting on the slope corresponding to the curve and the volume content of supercritical carbon dioxide, so as to accurately reflect the relationship between neutron porosity, density porosity and the volume content of supercritical carbon dioxide, and then the volume content of supercritical carbon dioxide in the oil reservoir can be accurately determined by using neutron porosity and density porosity, and the productivity of the oil reservoir can be accurately predicted. BRIEF DESCRIPTION OF DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a better understanding of the preferred embodiments, and are not intended to be a limitation on the application. Throughout the drawings, like referenced numerals will be used to designate like components.

[0039] In the drawings:

[0040] Figure 1 A flow chart of a method for determining the content of supercritical carbon dioxide in an oil reservoir according to an embodiment of the present application is shown;

[0041] Figure 2 A first curve diagram obtained by linear fitting of the neutron porosity and the density porosity of each oil well according to an embodiment of the present application is shown;

[0042] Figure 3 A first curve diagram obtained by fitting of the neutron porosity and the density porosity according to an embodiment of the present application when the volume content of supercritical carbon dioxide contained in different depths of the oil layer in the same oil well is substantially the same is shown;

[0043] Figure 4 A first curve diagram obtained by fitting of the neutron porosity and the density porosity according to an embodiment of the present application when the volume content of supercritical carbon dioxide contained in different depths of the oil layer in the same oil well is substantially different is shown;

[0044] Figure 5 A second curve diagram obtained by fitting of the slope value of the first curve and the corresponding volume content of supercritical carbon dioxide according to an embodiment of the present application is shown;

[0045] Figure 6 A structure diagram of a device for determining the content of supercritical CO2 in an oil reservoir according to an embodiment of the present application is shown;

[0046] Figure 7 A first curve diagram corresponding to a certain oil field according to an embodiment of the present application is shown;

[0047] Figure 8 A second curve diagram corresponding to a certain oil field according to an embodiment of the present application is shown;

[0048] Figure 9 A first curve diagram corresponding to the depth of 5460-5500 meters in an oil well to be explored according to an embodiment of the present application is shown;

[0049] Figure 10 A first curve diagram corresponding to the depth of 5500-5560 meters in an oil well to be explored according to an embodiment of the present application is shown;

[0050] Figure 11 Figure 1 shows a first curve diagram corresponding to a layer section of 5570-5660 meters in an oil well to be explored according to an embodiment of the present application. DETAILED DESCRIPTION

[0051] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0052] The present application mainly uses logging, core experiment and other data to study the influence of different content of supercritical carbon dioxide on density porosity and neutron porosity, finally establishes the difference relationship between different content of supercritical carbon dioxide and density porosity and neutron porosity, and numerically values the difference, so as to quickly and accurately calculate the volume content of supercritical carbon dioxide in the oil field to be explored and developed, provides well site deployment and test layer decision basis for oil and gas exploration and development, and guides oil and gas field exploration and development.

[0053] Among them, the neutron logging record is the hydrogen index, and the hydrogen index is the ratio of the number of hydrogen nuclei of any material per unit volume (1cm 3 ) to the number of hydrogen nuclei of the same volume of fresh water. Therefore, according to the definition, the hydrogen index of pure water layer is 1; and the hydrogen index of carbon dioxide is 0 because carbon dioxide does not contain hydrogen atoms; and the hydrogen index of liquid hydrocarbon is similar to that of water, and the hydrogen index of natural gas is very low. If the depth of oil and gas exploration is more than 5000 meters, the formation temperature and pressure are higher than the critical temperature and critical pressure of CO2, so that the carbon dioxide in the formation rock pore has special physical properties, and the density is close to the density of liquid. As can be seen, under the formation conditions, the oil and gas layer containing different content of supercritical carbon dioxide has different response characteristics on density porosity and neutron porosity. Therefore, the present application uses the difference relationship between different content of supercritical carbon dioxide and density porosity and neutron porosity to provide a method for determining the content of supercritical CO2 in the reservoir. As shown in the figure, the method mainly includes the following steps: Figure 1

[0054] S110, standardizing the old well logging data of a plurality of oil wells in the oil field to be explored, determining the neutron porosity and the density porosity in the whole well section of the reservoir based on the standardized old well logging data; when the content of supercritical CO2 in the whole well section is different, the neutron porosity and the density porosity corresponding thereto are also different.

[0055] ​In the same exploration oil field, including many old wells (explored wells) and new wells (just beginning to exploit wells), the embodiment is to use the logging data of the old wells to determine the relationship between the supercritical carbon dioxide and the density porosity and the neutron porosity, so as to determine the volume content of the supercritical carbon dioxide in the new well according to the relationship.

[0056] Based on this, the present application first needs to obtain the old well logging data of a plurality of exploited oil wells in the exploration oil field. The old well logging data may be affected by logging instruments, lithology, borehole conditions, mud invasion and other factors, and there is an error, which further leads to errors in the neutron porosity and the density porosity determined according to the old well logging data.

[0057] In order to improve the accuracy of subsequent supercritical CO2 content determination, the old well logging data of each oil well needs to be standardized, and then the neutron porosity and the density porosity in the whole well section of the reservoir are determined based on the standardized old well logging data. The whole well section of the reservoir generally includes oil layers, dry layers and water layers. Since the water layer and the dry layer do not contain crude oil, after the neutron porosity and the density porosity of the whole well section of the reservoir are determined, only the neutron porosity and the density porosity of the oil layer section are used for subsequent processing.

[0058] Specifically, the oil layer and the water layer can be identified based on a logging crossplot, logging, formation pressure regression fluid density and the like, so as to screen the neutron porosity and the density porosity corresponding to the oil layer from the neutron porosity and the density porosity of the whole well section.

[0059] In one embodiment, the old well logging data of a plurality of oil wells in the exploration oil field is standardized, including:

[0060] Reference density data and reference neutron data corresponding to a reservoir marker layer of a standard well are obtained; the reservoir marker layer includes a mudstone layer, a salt rock layer or a gypsum layer;

[0061] Current density data and current neutron data of the reservoir marker layer in the old well logging data are obtained, a density data calibration amount is determined based on the reference density data and the current density data, and a neutron data calibration amount is determined based on the reference neutron data and the current neutron data;

[0062] The density data of the remaining layer section in the old well logging data is calibrated based on the density data calibration amount, and the neutron data of the remaining layer section in the old well logging data is calibrated based on the neutron data calibration amount.

[0063] Since mudstone, salt rock, or gypsum layers are relatively stable, the data measured by different instruments under different conditions do not differ significantly. Therefore, this embodiment selects mudstone, salt rock, or gypsum layers from standard wells as marker layers. Each marker layer has a corresponding reference density data and a corresponding reference neutron data. Then, the current density data and current neutron data from the old well logging data are obtained. The difference between the reference density data and the current density data is used as the density data calibration value. The density data of the remaining segments in the old well logging data is calibrated based on the density data calibration value. Similarly, the difference between the reference neutron data and the current neutron data is used as the neutron data calibration value. The density data of the remaining segments in the old well logging data is calibrated based on the neutron data calibration value. This is to eliminate deviations caused by non-geological factors such as different instruments or calibration errors.

[0064] The selection criteria for standard wells are: (1) having relatively systematic drilling and coring data; (2) having strong regional representativeness in terms of structure, lithology, and oil-bearing properties; and (3) having a complete, accurate, and comprehensive logging series.

[0065] For example, assuming the formation density of the marker layer in a standard well is 2.5, and the formation density of the corresponding layer in the logging data of an old oil well is 2.55, then the calibration value is -0.05.

[0066] If the fluid density value of the old well logging data in the oil layer of the oil well is A, then the calibrated fluid density value should be A-0.05.

[0067] Then, the neutron porosity throughout the reservoir can be determined using standardized logging data from older wells, including:

[0068] According to the formula Determine the formation clay content V SH ;

[0069] To obtain the neutron porosity in pure mudstone layers from old well logging data, according to the formula Φ N =Φ log -V SH *Φ Nsh Determine the neutron porosity Φ in the remaining segments N ;in,

[0070] SH is the clay content index, and GCUR is a regional empirical constant, which can be determined based on mining experience or fitted core data, and is not limited here. Φ log The neutron value for the entire well section, Φ Nsh Neutron porosity of pure mudstone layers in old well logging data.

[0071] The mud quality index SH is determined as follows:

[0072] According to the formula determine the shale index SH; wherein,

[0073] GR is the true natural gamma value of the current interval in the old well logging data, GR max is the pre-set maximum natural gamma value, GR min is the pre-set minimum natural gamma value.

[0074] It should be noted that the true natural gamma value corresponding to different intervals and different depth sections of the whole well section of the oil well should be different, and the maximum natural gamma value and the minimum natural gamma value can be found in the corresponding old well logging data of the whole well section, so as to determine the corresponding shale index of each interval according to the above formula.

[0075] And the neutron porosity of pure mudstone layer can be directly read from the old well logging data, and the neutron porosity of other intervals needs to be further calculated. Then after obtaining the neutron porosity of the pure mudstone layer, the neutron porosity of other intervals can be determined according to the above formula.

[0076] After the neutron porosity is determined, the density porosity of the whole well section also needs to be determined. In one embodiment, the density porosity in the whole well section of the oil reservoir is determined based on the normalized old well logging data, comprising:

[0077] According to the formula determine the density porosity Φ D of the whole well section of the oil reservoir; wherein,

[0078] ρ b is the formation density value in the old well logging data, ρ ma is the matrix density value in the old well logging data, ρ f is the fluid density value in the old well logging data, ρ sh is the pure mudstone density value in the old well logging data, V SH is the shale content of the formation in the old well logging data.

[0079] In this way, the neutron porosity and the density porosity of the whole well section in each oil well can be determined in the above manner.

[0080] S111, remove the abnormal neutron porosity and density porosity of the oil layer, and obtain the normal neutron porosity and density porosity;

[0081] The oil layer can also include a tight layer, which is generally considered as a dry layer without fluid, so the neutron porosity and density porosity of the dry layer are not helpful for determining the supercritical carbon dioxide content, and thus the abnormal neutron porosity and density porosity in the oil layer, i.e., the neutron porosity and density porosity of the dry layer in the oil layer section, need to be removed.

[0082] In actual removal, a neutron porosity threshold (for example, 5%) and a density porosity threshold (for example, 5%) are set in advance, the neutron porosity lower than the neutron porosity threshold is removed, and the remaining neutron porosity is the normal neutron porosity. Similarly, the density porosity lower than the density porosity threshold is removed, and the remaining density porosity is the normal density porosity.

[0083] In S112, for each oil well, a first curve is fitted based on the normal neutron porosity and the normal density porosity, a slope value corresponding to each first curve is determined, and the volume content of supercritical carbon dioxide contained in the oil well is determined.

[0084] For each oil well, after the normal density porosity and the normal neutron porosity are determined, a first curve can be fitted based on the normal neutron porosity and the normal density porosity, and a slope value corresponding to each first curve is determined.

[0085] In an embodiment, fitting the first curve based on the normal neutron porosity and the normal density porosity includes:

[0086] For each oil well, the normal neutron porosity and the normal density porosity are linearly fitted based on a preset curve fitting function to obtain a first curve; the first curve has a linear characteristic.

[0087] As described above, since only the oil layer contains crude oil, the curve fitting in this embodiment is actually only performed on the normal neutron porosity and the normal density porosity in the oil layer. Then for each oil well, the neutron porosity and the density porosity at different depths in the oil layer can be fitted by using a curve fitting function to obtain a first curve y=kix; where y is the neutron porosity, x is the density porosity, i is the oil well number, and k i is the slope value corresponding to the first curve. i

[0088] The first curve of each oil well can refer to Figure 2 , Figure 2 The first curves corresponding to multiple oil wells are shown as y=k1x, y=k2x, y=k3x, y=k4x, y=k5x, y=k6x, y=k7x, y=k8x, and y=k9x.

[0089] ​It should be noted that, generally speaking, if the volumetric supercritical carbon dioxide content at different depths of the oil layer in the same oil well is roughly the same, then the neutron porosity and density porosity of that oil well will only fit a single curve, such as... Figure 3 As shown. However, if the volumetric supercritical carbon dioxide content at different depths of the oil layer in the same oil well varies significantly, this situation may result in two first curves being fitted, such as... Figure 4 As shown.

[0090] To visually demonstrate the relationship between the volumetric content of supercritical carbon dioxide in the oil well and the slope of the first curve, it is necessary to further determine the volumetric content of supercritical carbon dioxide in the oil well and establish the intersection relationship between the slope of the first curve and the corresponding volumetric content of supercritical carbon dioxide.

[0091] It should be noted that after the old wells are extracted, crude oil samples can be obtained and analyzed to obtain the supercritical carbon dioxide volume content for each extracted well. Thus, once the first curves relating supercritical carbon dioxide volume content, neutron porosity, and density porosity are determined for each well, the intersection relationship between these first curves and the corresponding supercritical carbon dioxide volume content can be established.

[0092] The intersection relationship is essentially used to characterize the relationship between the slope value of the first curve and the volume content of supercritical carbon dioxide. The intersection relationship can be presented in the form of a table, document or graph, and there is no restriction here.

[0093] For example, assuming it is presented in graphic form, it can be... Figure 2 Add the corresponding supercritical carbon dioxide volume content to the first curve in the graph. For the first curve with a slope value of k1, the corresponding supercritical carbon dioxide volume content is V1.

[0094] When presented in tabular form, the first curve can be paired with the corresponding supercritical carbon dioxide volume content in the table.

[0095] Because supercritical carbon dioxide has a relatively small effect on density porosity but a significant effect on neutron porosity, and the higher the carbon dioxide content, the smaller the neutron porosity and the smaller the slope value. That is, if k1>k2>k3>……k i Then V1 <V2<……Vi。

[0096] S113, Fit a second curve based on the slope value of each of the first curves and the supercritical carbon dioxide volume content in the corresponding oil well;

[0097] When the intersection relationship between the first curve and the corresponding supercritical carbon dioxide volume content is determined, the supercritical carbon dioxide volume content of the new well in the exploration oilfield can also be determined based on the intersection relationship, but only a rough range can be determined, and the supercritical carbon dioxide volume content cannot be quantitatively determined.

[0098] For example, assuming that the slope value of the first curve corresponding to the density porosity and the neutron porosity of the new well in the exploration oilfield is between k2 and k3, it indicates that the critical carbon dioxide volume content contained in the new well in the exploration oilfield is between V2 and V3.

[0099] Therefore, in order to accurately and quantitatively determine the supercritical carbon dioxide volume content in the exploration oilfield, a second curve needs to be fitted based on the slope value corresponding to the first curve and the supercritical carbon dioxide volume content in the corresponding oil well. The second curve can represent the relationship between the slope value of the first curve and the supercritical carbon dioxide volume content.

[0100] Specifically, for example, the supercritical carbon dioxide volume content corresponding to k1 is V1, the supercritical carbon dioxide volume content corresponding to k2 is V2, and the supercritical carbon dioxide volume content corresponding to k3 is V3. i If the slope value k of the first curve is k2 and the corresponding supercritical carbon dioxide volume content is V2, then the slope value k of the first curve and the corresponding supercritical carbon dioxide volume content V2 can be fitted to obtain a second curve. The second curve also has a linear relationship, and the slope value of the second curve gradually decreases as the dissolved carbon dioxide volume content in the liquid hydrocarbon increases. i

[0101] In an embodiment, fitting the second curve based on the slope value corresponding to each first curve and the supercritical carbon dioxide volume content in the corresponding oil well comprises:

[0102] Linearly fitting the slope value corresponding to each first curve and the supercritical carbon dioxide volume content in the corresponding oil well based on a preset curve fitting function to obtain a second curve, and the function corresponding to the second curve is:

[0103] wherein,

[0104] is the supercritical carbon dioxide volume content, K is the slope of the second curve, n is a constant, and m is a constant.

[0105] For example, assuming that the slope value corresponding to the first curve and the supercritical carbon dioxide volume content in the above multiple oil wells are fitted to obtain a second curve, which can be referred to as Figure 5 .

[0106] S114, determining the supercritical carbon dioxide volume content of the new well in the exploration oilfield according to the second curve. ​

[0107] After the function corresponding to the second curve is determined, when it is necessary to measure the volume content of supercritical carbon dioxide contained in a new well in the same exploration oilfield, only the slope value of the corresponding first curve needs to be determined according to the logging data of the new well, and then the volume content of supercritical carbon dioxide in the exploration oilfield is quantitatively determined based on the slope value of the first curve and the function corresponding to the second curve.

[0108] For example, assuming that the slope value of the first curve corresponding to the density porosity and the neutron porosity of the new well in the exploration oilfield is 90, 90 can be substituted into the function corresponding to the second curve to obtain a corresponding volume content of supercritical carbon dioxide.

[0109] The present application performs curve fitting on the corresponding relationship between the fitting curve of the neutron porosity and the density porosity and the content of supercritical carbon dioxide, and further performs quadratic fitting on the slope corresponding to the curve and the volume content of supercritical carbon dioxide, so that the relationship between the neutron porosity, the density porosity and the volume content of supercritical carbon dioxide can be accurately reflected, and the volume content of supercritical carbon dioxide in the new well of the oilfield can be accurately determined by using the neutron porosity and the density porosity, and the reservoir productivity can be accurately predicted.

[0110] Based on the same inventive concept as in the foregoing embodiments, the present embodiment also provides a device for determining the content of supercritical CO2 in a reservoir, as shown in Figure 6 The device comprises:

[0111] A data processing unit 61 is configured to perform standardization processing on the well logging data of old wells of a plurality of oil wells in an exploration oilfield, determine the neutron porosity and the density porosity of the whole well section of the reservoir based on the standardization well logging data of the old wells, and remove abnormal neutron porosity and density porosity in the oil layer to obtain normal neutron porosity and density porosity, when the content of supercritical CO2 at each depth in the whole well section is different, the corresponding neutron porosity and density porosity are also different.

[0112] A first fitting unit 62 is configured to fit a first curve based on the normal neutron porosity and the density porosity for each oil well, determine the slope value corresponding to each first curve, and determine the volume content of supercritical carbon dioxide contained in the oil well.

[0113] A second fitting unit 63 is configured to fit a second curve based on the slope value corresponding to each first curve and the volume content of supercritical carbon dioxide in the corresponding oil well.

[0114] A determination unit 64 is configured to determine the volume content of supercritical carbon dioxide of a new well in the exploration oilfield according to the second curve.

[0115] The device is used for the method for determining the content of supercritical CO2 in an oil reservoir according to the embodiments of the present application, and therefore the specific structure and deformation of the device can be understood by those skilled in the art based on the method according to the embodiments of the present application, and therefore will not be described here again. The device used by the method according to the embodiments of the present application belongs to the scope of the present application.

[0116] In practical applications, when the method and device provided by the above embodiments are used to determine the volume content of supercritical carbon dioxide in an oil field, the following is achieved:

[0117] First, the logging data is standardized, and then the neutron porosity and density porosity values of the whole well section are calculated, and the neutron porosity and density porosity lower than 0.05 are removed, and then a first curve is fitted according to the normal neutron porosity and density porosity. The first curve is as shown in Figure 7 .

[0118] In Figure 7 , it can be seen that the slope value of the first curve and the corresponding volume content of supercritical carbon dioxide, for example, k1 is 1.23, and the corresponding V1 is less than 5%; k2 is 0.95, and the corresponding V2 is 12%; k3 is 0.8275, and the corresponding V3 is 25%; k4 is 0.779, and the corresponding V4 is 42.5%; k5 is 0.661, and the corresponding V5 is 45%; k6 is 0.586, and the corresponding V6 is 60%; k7 is 0.427, and the corresponding V7 is 67%; k8 is 0.279, and the corresponding V8 is 76.5%; k9 is -0.067, and the corresponding V9 is greater than 95%.

[0119] Then, the slope value of the first curve and the corresponding volume content of supercritical carbon dioxide are curve fitted to obtain a second curve, as shown in Figure 8 . Figure 8 The function corresponding to the second curve in

[0120]

[0121] When the second curve is used to determine the volume content of supercritical carbon dioxide in a to-be-explored oil well in a certain basin, it is determined that the first curve corresponding to the depth of 5460-5500 meters in the to-be-explored oil well is y=0.7383x+0.0396 according to Figures 9-11 .

[0122] The first curve corresponding to the depth of 5500-5560 meters is

[0123] y=0.7482x+0.0471.

[0124] The first curve corresponding to the depth of 5570-5660 meters is

[0125] y = 0.7168x + 0.0165.

[0126] Wherein, the slope value of the first curve corresponding to the depth section of 5460-5500 meters is 0.7383, the supercritical carbon dioxide volume content of 46.5% can be obtained by substituting the slope value into the function corresponding to the second curve, and the supercritical carbon dioxide volume content of 44% in the depth section is determined by sampling analysis during later exploitation.

[0127] The slope value of the first curve corresponding to the depth section of 5500-5560 meters is 0.7482, the supercritical carbon dioxide volume content of 45.755% can be obtained by substituting the slope value into the function corresponding to the second curve, and the supercritical carbon dioxide volume content of 44% in the depth section is determined by sampling analysis during later exploitation.

[0128] The slope value of the first curve corresponding to the depth section of 5570-5660 meters is 0.7168, the supercritical carbon dioxide volume content of 47.98% can be obtained by substituting the slope value into the function corresponding to the second curve, and the supercritical carbon dioxide volume content of 45% in the depth section is determined by sampling analysis during later exploitation.

[0129] It can be seen that the test error is less than 5% when the supercritical carbon dioxide volume content is determined by using the method of the present application, and the accuracy is high.

[0130] Based on the same inventive concept, the embodiment provides a computer device, as shown in the figure, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to realize any step of the method described above.

[0131] Based on the same inventive concept, the embodiment provides a computer readable storage medium, as shown in the figure, which stores a computer program, and the computer program is executed by the processor to realize the steps of any method described above.

[0132] Through one or more embodiments of the present application, the present application has the following beneficial effects or advantages:

[0133] The application provides a method, device, medium and equipment for determining supercritical CO2 content in an oil reservoir, the method comprising: performing standardization processing on old well logging data of a plurality of oil wells in an exploration oil field, determining neutron porosity and density porosity of the whole well section of the oil reservoir based on the standardization processed old well logging data; when the supercritical CO2 content at each depth in the whole well section is different, the corresponding neutron porosity and density porosity are also different; removing abnormal neutron porosity and density porosity of the oil layer, and obtaining normal neutron porosity and density porosity; for each oil well, fitting a first curve based on the normal neutron porosity and density porosity, determining a slope value corresponding to each first curve; determining the supercritical carbon dioxide volume content contained in the oil well; fitting a second curve based on the slope value corresponding to each first curve and the supercritical carbon dioxide volume content in the corresponding oil well; determining the supercritical carbon dioxide volume content of a new well in the exploration oil field according to the second curve; thus, since the effects of supercritical carbon dioxide with different contents on neutron porosity and density porosity are different, the application performs curve fitting on the corresponding relationship between the fitting curves of neutron porosity and density porosity and the supercritical carbon dioxide content, and further performs secondary fitting on the slope corresponding to the curve and the supercritical carbon dioxide volume content, so that the relationship between neutron porosity, density porosity and the supercritical carbon dioxide volume content can be accurately reflected, and then the supercritical carbon dioxide volume content of the new well in the oil reservoir can be accurately determined by using neutron porosity and density porosity, and the oil reservoir productivity can be accurately predicted.

[0134] The algorithms and displays presented herein are not inherently related to any particular computer, virtual system, or other apparatus. Various general purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will be apparent from the description above. In addition, the present application is not intended to be limited to any particular programming language. It will be appreciated that there are many programming languages that can be used to implement the teachings herein, and any such programming language can be used in connection with the teachings herein.

[0135] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order to not obscure the understanding of this description.

[0136] Similarly, it is to be understood that the embodiments of the present application can be placed into practice notwithstanding modifications to form yet further embodiments of the present application. As such, the terms and expressions of the foregoing description are used solely by way of the example thereof, but to the extent possible no limitation is intended to the details of the construction described herein other than as described in the claims. In this manner, the embodiments of the present application as described herein are susceptible to modifications and alternative forms known to those skilled in the art. It is, therefore, desired to be protected in the broadest scope of the appended claims as they can be interpreted to cover the subject matter of the above description.

[0137] Those skilled in the art can appreciate that modules in the apparatus in the embodiments can be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and further can be divided into multiple sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or apparatus of all the processes or units disclosed in the specification as such can be adopted in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless explicitly stated otherwise, each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature providing the same, equivalent or similar function.

[0138] Furthermore, those skilled in the art will appreciate that the features of the various embodiments can be combined with each other, as the combinations of features from different embodiments are within the scope of the present application and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0139] The various component embodiments of the present application can be implemented in hardware, or as software modules running in one or more processors, or in combinations thereof. As will be appreciated by one skilled in the art, a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functionality of some or all of the components in the gateway, proxy server, system according to embodiments of the present application. The present application can also be implemented as a program of instructions for performing part or all of the methods described herein, e.g., a computer program and a computer program product. Such program of the present application can be stored on a computer readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier medium, or in any other form.

[0140] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the system claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The use of the word 'at least' followed by a list of one or more items means that any item in the list can be present or there can be more than one of a certain item. The use of the terms 'first','second' and 'third', etc. does not limit the quantity and / or order of those terms. These terms are used to distinguish between two entities or steps involved with the application and are not necessarily used to describe a 'first','second' or 'third' or the like by their appearance or order of appearance in the claims or description.

[0141] Although preferred embodiments of the application have been described herein, additional changes and modifications can be suggested to one skilled in the art, particularly in light of the essential novel teachings herein. The disclosures herein are intended to cover such modifications and changes as can fall within the scope of the appended claims.

[0142] The above-described embodiments are merely given as examples and are not intended to limit the scope of the present application. Various modifications made within the scope of the application based on the principles of the application should be considered as falling within the scope of the application.

Claims

1. A method of determining the content of supercritical CO2 in a reservoir, characterized in that, The method comprises: standardizing old well logging data of a plurality of oil wells in an exploration oilfield, determining neutron porosity and density porosity of a whole well section of an oil reservoir based on the standardized old well logging data; when supercritical CO2 content at each depth in the whole well section is different, the corresponding neutron porosity and the density porosity are also different; removing abnormal neutron porosity and density porosity in an oil layer to obtain normal neutron porosity and density porosity; for each oil well, fitting a first curve based on the normal neutron porosity and the density porosity, determining a slope value corresponding to each first curve, and determining the volume content of supercritical carbon dioxide contained in the oil well; fitting a second curve based on the slope value corresponding to each first curve and the volume content of supercritical carbon dioxide in the corresponding oil well; determining the volume content of supercritical carbon dioxide of a new well in the exploration oilfield according to the second curve; wherein fitting a second curve based on the slope value corresponding to each first curve and the volume content of supercritical carbon dioxide in the corresponding oil well comprises: linearly fitting, based on a preset curve fitting function, the slope value corresponding to each of the first curves and the supercritical carbon dioxide volume content in the corresponding oil well, to obtain a second curve, the function corresponding to the second curve being: wherein, The is the supercritical carbon dioxide volume content, k is the slope of the second curve, n is a constant, and m is a constant.

2. The method of claim 1, wherein, the standardizing old well logging data of a plurality of oil wells in an exploration oilfield comprises: obtaining reference density data and reference neutron data corresponding to an oil reservoir marker layer of a standard well; the oil reservoir marker layer comprises a mudstone layer, a salt rock layer or a gypsum layer; obtaining current density data and current neutron data of the oil reservoir marker layer in the old well logging data, determining a density data calibration amount based on the reference density data and the current density data, and determining a neutron data calibration amount based on the reference neutron data and the current neutron data; calibrating density data of a remaining layer section in the old well logging data based on the density data calibration amount, and calibrating neutron data of the remaining layer section in the old well logging data based on the neutron data calibration amount.

3. The method of claim 1, wherein, the determining neutron porosity of a whole well section of an oil reservoir based on standardized old well logging data comprises: According to the formula determining the formation shale content V SH ; The neutron porosity in the pure mudstone layer in the old well logging data is obtained, and the neutron porosity Φ N in the remaining layer section is determined according to the formula log Φ SH = Φ Nsh - V N ; wherein, SH is the shale index, GCUR is the regional empirical constant, Φ log is the neutron value in the whole well section, Φ Nsh is the neutron porosity of the pure shale layer in the old well logging data.

4. The method of claim 1, wherein, the determining density porosity of a whole well section of an oil reservoir based on standardized old well logging data comprises: According to the formula The density porosity Φ in the whole well section of the reservoir is determined D ; wherein, ρ b is a formation density value in the well log data for the old well, p ma is a matrix density value in the well log data for the old well, the p f is a fluid density value in the well log data for the old well, the p sh is a pure shale density value in the well log data for the old well, the V SH is a formation shale content in the well log data for the old well.

5. The method of claim 3, wherein, the method further comprises: According to the formula determining a shale index SH; wherein, The GR is the true natural gamma value of the current interval in the well logging data of the old well, the GR max is the preset maximum natural gamma value, the GR min is the preset minimum natural gamma value.

6. The method of claim 1, wherein, the fitting a first curve based on the normal neutron porosity and the density porosity comprises: for each oil well, performing linear fitting on the normal neutron porosity and the density porosity based on a preset curve fitting function to obtain a first curve; the first curve has linear characteristics.

7. An apparatus for determining the amount of supercritical CO2 in a reservoir, comprising: The device comprises: a data processing unit configured to standardize old well logging data of a plurality of oil wells in an exploration oilfield, determine neutron porosity and density porosity of a whole well section of an oil reservoir based on the standardized old well logging data, and remove abnormal neutron porosity and density porosity in an oil layer to obtain normal neutron porosity and density porosity; when supercritical CO2 content at each depth in the whole well section is different, the corresponding neutron porosity and the density porosity are also different; a first fitting unit configured to, for each oil well, fit a first curve based on the normal neutron porosity and the density porosity, determine a slope value corresponding to each first curve, and determine the volume content of supercritical carbon dioxide contained in the oil well; a second fitting unit configured to fit a second curve based on the slope value corresponding to each of the first curves and the volume content of supercritical carbon dioxide in the corresponding oil well; a determining unit configured to determine the volume content of supercritical carbon dioxide in a new well of the oilfield according to the second curve; and the fitting of the second curve based on the slope value corresponding to each of the first curves and the volume content of supercritical carbon dioxide in the corresponding oil well comprises: linearly fitting, based on a preset curve fitting function, the slope value corresponding to each of the first curves and the supercritical carbon dioxide volume content in the corresponding oil well, to obtain a second curve, the function corresponding to the second curve being: V co2 = m*k + n; wherein, The is the supercritical carbon dioxide volume content, k is the slope of the second curve, n is a constant, and m is a constant.

8. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the steps of the method of any one of claims 1-6.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the steps of the method of any one of claims 1-6.

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