While-drilling gamma-ray energy spectrum acquisition method and while-drilling gamma-ray energy spectrum correction method and system
The multi-dimensional energy spectrum correction model corrects the gamma energy spectrum logging data while drilling, which solves the multi-factor coupling effect of the formation environment on the measurement results, achieves more accurate logging data, and provides more reliable data support for subsequent work.
Patent Information
- Application Number
- CN202311541472.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-17
- Publication Date
- 2025-05-20
AI Technical Summary
The existing gamma energy spectrum logging technology while drilling fails to effectively consider the multi-factor coupling effect of the formation environment on the measurement results, resulting in inaccuracy of the measurement results, affecting subsequent logging interpretation and geological guidance work.
A multi-dimensional energy spectrum correction model is adopted to obtain multi-level energy count statistics of the measured gamma energy spectrum while drilling, and combine actual data such as well as well as well as a multi-dimensional correction to establish a correction model to adjust the measurement results.
It effectively reduces the impact of the formation environment on the measurement results, enables the logging instrument to more realistically reflect the formation information, and provides more accurate data guarantees for subsequent logging interpretation and geologically guided results.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of petroleum logging, and particularly relates to a method for collecting gamma energy spectrum while drilling, an energy spectrum correction method and a system therefor. Background Art
[0002] With the increasing demand for oil and gas, the drilling targets are moving towards deeper and more complex highly deviated wells and horizontal wells. Traditional logging methods can no longer meet the construction requirements. As a key technical means in drilling engineering, logging while drilling technology is widely used in the fields of oil exploration and exploitation. Logging while drilling technology can measure formation information in real time while drilling through the formation. By measuring the propagation speed and attenuation degree of waves in the drilling fluid, formation parameters are obtained, providing data for subsequent analysis of the formation situation.
[0003] As an essential device in the logging while drilling series of instruments, the gamma energy spectrum logging tool while drilling is applied to the drilling construction of directional wells and horizontal wells for formation lithology judgment, including calculation of shale content, identification of clay types, identification of metamorphic rock lithology, etc. Most of the gamma rays emitted by the formation are generated by the decay of three radioactive isotopes of petroleum: potassium, uranium, and thorium. The gamma energy spectrum logging tool determines the contents of potassium, uranium, and thorium in the formation according to the different energy spectrum characteristics of the γ rays emitted during the decay of potassium, uranium, and thorium radioactive nuclides. However, during the instrument measurement process, due to different wellbore conditions and mud specific gravities in different geological environments, there will be certain differences in the measurement results of the gamma energy spectrum while drilling, thus affecting subsequent reservoir evaluation, logging interpretation and other related work.
[0004] In the prior art, the Monte Carlo method is usually used to simulate the responses of the azimuthal gamma energy spectrum logging while drilling under different wellbore and formation conditions, obtain the influence laws of drilling fluid density, KCL content in the drilling fluid, formation matrix, and the dip angle, azimuth angle, and thickness of the inclined radioactive formation on the azimuthal gamma energy spectrum logging while drilling. On this basis, a correction method for gamma energy spectrum measurement is given. However, this method only considers the influence of non-formation factors on the measurement results. In actual drilling work, the measurement results of the gamma energy spectrum logging while drilling are mainly affected by multiple factors such as formation and non-formation. At present, there is no relevant complete patent.
[0005] It can be seen that with the wide application of the gamma energy spectrum logging while drilling technology, there is currently no multi-factor coupling correction scheme. If the influence of the formation environment on the measurement results cannot be reduced, it will bring adverse results to subsequent logging interpretation work.
[0006] In summary, in order to reduce the influence of the formation environment on the measurement results of the gamma energy spectrum while drilling and provide data guarantee for subsequent logging interpretation and geosteering results, it is crucial for the prior art to establish a correction scheme for the gamma energy spectrum while drilling. Summary of the Invention
[0007] The present invention aims to provide a scheme for correcting and collecting gamma ray spectrometry while drilling, so as to fully consider the influence of the formation environment on the measurement data during the actual logging process and realize multi-dimensional correction of the gamma ray spectrometry while drilling data.
[0008] To solve the above technical problems, an embodiment of the present invention provides a correction method for adjusting gamma ray spectrometry while drilling, including: obtaining the count statistical data of multi-level energies of the measured gamma ray spectrometry while drilling; according to the multi-level energy spectrum count data, combining the actual data of the measured well under different dimensions, and using a preset multi-dimensional energy spectrum correction model to perform multi-dimensional correction on the count data of each level of the energy spectrum respectively. The correction dimensions include: hole size, mud density, KCL concentration, and barite content.
[0009] Preferably, the multi-dimensional energy spectrum correction model is constructed in the following manner: according to the gamma ray spectrometry data under different hole size conditions, analyze the influence of the hole diameter on the change of the spectrum data, so as to obtain a hole diameter correction expression for correcting the spectrum data in the hole size dimension; according to the gamma ray spectrometry data under different mud density conditions, analyze the influence of the mud density on the change of the spectrum data, so as to obtain a mud density correction expression for correcting the spectrum data in the mud density dimension; according to the gamma ray spectrometry data under different KCL contents in the mud, analyze the influence of the internal KCL content on the change of the spectrum data, so as to obtain a KCL content correction expression for correcting the spectrum data in the KCL content dimension; according to the gamma ray spectrometry data under different barite contents in the mud, analyze the influence of the barite content on the change of the spectrum data, so as to obtain a barite content correction expression for correcting the spectrum data in the barite content dimension; fuse the hole diameter correction expression, the mud density correction expression, the KCL content correction expression, and the barite content correction expression to establish a multi-dimensional energy spectrum correction model.
[0010] Preferably, in the process of constructing the hole diameter correction expression, it includes: according to the multi-level energy spectrum count data of the gamma ray spectrometry data under different hole size conditions of the standard calibration well, establish a hole diameter correction factor chart representing the relationship between different hole diameter conditions and the multi-level energy spectrum count data, so as to obtain the hole diameter correction expression, where the hole diameter correction expression is represented by the following formula:
[0011]
[0012] where, X′ n represents the theoretical value of the multi-level energy spectrum count data, X n represents the multi-level energy spectrum count data measured in the standard calibration well under different hole size conditions, r bh represents the hole size, r sondeLet \(D\) represent the detector size, \(t\) represent the correlation coefficient related to the detector size, and \(k\) represent the correlation coefficient related to the borehole size.
[0013] Preferably, in the process of constructing the mud density correction expression, it includes: based on the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different mud density conditions, establishing a mud density correction factor chart representing the relationship between different mud density conditions and the multi-level energy spectrum count data, so as to obtain the mud density correction expression, where the mud density correction expression is represented by the following formula:
[0014]
[0015] where \(X'\) n represents the theoretical value of the multi-level energy spectrum count data, and \(X\) n represents the multi-level energy spectrum count data measured in the standard calibration well under different mud density conditions, \(\mu\) represents the correlation parameter related to the mud density, and \(\rho\) mud represents the mud density.
[0016] Preferably, in the process of constructing the KCL content correction expression, it includes: based on the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different KCL content conditions in the mud, establishing a KCL content correction factor chart representing the relationship between different KCL content conditions and the multi-level energy spectrum count data, so as to obtain the KCL content correction expression, where the KCL content correction expression is represented by the following formula:
[0017] X' n =X n (a\(\rho\) kcl 2 +b\(\rho\) kcl +c)
[0018] where, in the formula, \(X'\) n represents the theoretical value of the multi-level energy spectrum count data, \(X\) n represents the multi-level energy spectrum count data measured in the standard calibration well under different KCL content conditions, \(\rho\) kcl represents the KCL content in the mud, and \(a\), \(b\), and \(c\) respectively represent the correlation coefficients related to the KCL concentration.
[0019] Preferably, in the process of constructing the barite content correction expression, it includes: based on the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different barite content conditions in the mud, establishing a barite content correction factor chart representing the relationship between different barite content conditions and the multi-level energy spectrum count data, so as to obtain the barite content correction expression, where the barite content correction expression is represented by the following formula:
[0020] X′ n = X n (a′ρ b 2 + b′ρ b + c′)
[0021] where X′ n represents the theoretical value of the multi - level energy spectrum counting data, X n represents the multi - level energy spectrum counting data measured in the standard calibration well under different barite content conditions, ρ kcl represents the barite content in the mud, and a′, b′, c′ respectively represent the correlation coefficients related to the barite content.
[0022] Preferably, the multi - dimensional energy spectrum correction model is expressed by the following expression:
[0023] W′ (r) = W (r) sd[1 - e mn
[0024] where m represents the correction coefficient for the wellbore diameter dimension, m = k(r bh - r sonde ) + t, r bh represents the borehole size of the measured well, r sonde represents the detector size of the measured well, t and k respectively represent the chart - related coefficients in the wellbore diameter correction expression, n represents the correction coefficient for the mud density dimension, n = - μρ mud , μ represents the chart - related coefficient in the mud density correction expression, ρ mud represents the mud density of the measured well, s represents the correction coefficient for the KCL concentration dimension, s = (aρ kcl 2 + bρ kcl + c), ρ kcl represents the KCL content in the mud of the measured well, a, b, c respectively represent the chart - related coefficients in the KCL content correction expression, d represents the correction coefficient for the barite content dimension, d = (a′ρ b 2 + b′ρ b + c′), ρ kcl represents the barite content in the mud of the measured well, a′, b′, c′ respectively represent the chart - related coefficients in the barite content correction expression, W (r) represents the multi - level energy spectrum counting data before correction, and W′ (r) represents the multi - dimensional energy spectrum counting data after correction.
[0025] Preferably, the multi - level energy spectrum counting data is five - energy - spectrum counting data.
[0026] In addition, an embodiment of the present invention further provides a calibration system for adjusting the measurement of gamma energy spectrum while drilling, including: a full-spectrum data input module configured to obtain the count statistical data of multi-level energies of the measured gamma energy spectrum while drilling; a calibration processing module that, according to the multi-level energy spectrum count data, combines the actual data of the measured well in different dimensions, and uses a preset multi-dimensional energy spectrum calibration model to perform multi-dimensional calibration on the count data of each level of the energy spectrum respectively. The calibration dimensions include: wellbore size, mud density, KCL concentration, and barite content.
[0027] In addition, an embodiment of the present invention further provides a method for collecting gamma energy spectrum while drilling, including: during the measurement while drilling, performing real-time gamma energy spectrum measurement on the measured well; dividing the measurement data of the gamma energy spectrum while drilling into multi-level energies according to different energy levels and performing statistical counting on the spectrum data at different energy levels; calibrating the count data of the multi-level energy spectrum respectively according to the calibration method for adjusting the measurement of the gamma energy spectrum while drilling; performing weighted matrix operation on the calibrated count data of the multi-level energy spectrum to obtain the true potassium, uranium, and thorium contents.
[0028] Compared with the prior art, one or more of the above embodiments may have the following advantages or beneficial effects:
[0029] The present invention proposes a method for collecting gamma energy spectrum while drilling, its energy spectrum calibration method, and system. The present invention solves the problem that the existing measurement method fails to simultaneously consider the influence of well diameter, mud density, KCL concentration, and barite content on the measurement data. During the measurement while drilling, real-time gamma energy spectrum measurement is performed on the measured well, and the measurement data of the gamma energy spectrum while drilling is divided into multi-level energies. Combining the actual data of the measured well in different dimensions, a preset multi-dimensional energy spectrum calibration model is used to perform multi-dimensional calibration on the count data of each level of the energy spectrum, so as to adjust the measurement result of the gamma energy spectrum while drilling based on the calibration dimensions of wellbore size, mud density, KCL concentration, and barite content. The present invention can effectively reduce the influence of the formation environment on the measurement result, enable the logging instrument to more truly reflect the formation information, and provide more accurate data guarantee for subsequent logging interpretation and geological steering results.
[0030] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings
[0031] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:
[0032] Figure 1 This is a schematic diagram of the steps of the calibration method for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0033] Figure 2 This is a schematic flow chart of the calibration method for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0034] Figure 3 This is an exemplary chart of the borehole size correction factor in the calibration method for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0035] Figure 4 This is an exemplary chart of the mud density correction factor in the calibration method for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0036] Figure 5 This is an exemplary chart of the KCL content correction factor in the calibration method for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0037] Figure 6 This is a schematic diagram of the overall structure of the calibration system for adjusting the measurement of gamma ray spectroscopy while drilling according to an embodiment of the present application.
[0038] Figure 7 This is a schematic diagram of the steps of the gamma ray spectroscopy acquisition method while drilling according to an embodiment of the present application. Detailed implementation manners
[0039] The following will describe in detail the implementation manners of the present invention in combination with the accompanying drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.
[0040] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.
[0041] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments. Unless the context clearly dictates otherwise, the singular forms "a", "an" used herein are also intended to include the plural. It should also be understood that the terms "comprises" and / or "comprising" specify the presence of the stated features, integers, steps, operations, units and / or components, without precluding the presence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.
[0042] With the increasing demand for oil and gas, the drilling targets are moving towards deeper and more complex highly deviated wells and horizontal wells. Traditional logging methods can no longer meet the requirements of construction. As a key technical means in drilling engineering, logging-while-drilling technology is widely used in the fields of oil exploration and production. Logging-while-drilling technology can measure formation information in real time while drilling through the formation. By measuring the propagation speed and attenuation degree of waves in the drilling fluid, formation parameters are obtained, providing data for subsequent analysis of the formation situation.
[0043] As an essential device in the logging-while-drilling series of instruments, the gamma-ray spectroscopy logging-while-drilling tool is applied in the drilling construction of directional wells and horizontal wells for formation lithology judgment, including the calculation of shale content, the identification of clay types, the identification of metamorphic rock lithology, etc. Most of the gamma rays emitted by the formation are generated by the decay of three radioactive isotopes in oil: potassium, uranium, and thorium. The gamma-ray spectroscopy logging-while-drilling tool determines the contents of potassium, uranium, and thorium in the formation according to the different energy spectrum characteristics of the γ-rays emitted during the decay of potassium, uranium, and thorium radioactive nuclides. However, during the instrument measurement process, the borehole conditions and mud specific gravity in different geological environments are different, and there will be certain differences in the measurement results of the gamma-ray spectroscopy logging-while-drilling, thus affecting subsequent reservoir evaluation, logging interpretation and other related work.
[0044] In the prior art, the Monte Carlo method is usually used to simulate the response of azimuthal gamma-ray spectroscopy logging-while-drilling under different borehole and formation conditions, obtain the influence laws of drilling fluid density, KCL content in the drilling fluid, formation matrix, and the dip angle, azimuth angle, and thickness of the inclined radioactive formation on azimuthal gamma-ray spectroscopy logging-while-drilling. On this basis, a correction method for gamma-ray spectroscopy measurement is given. However, this method only considers the influence of non-formation factors on the measurement results. In actual drilling work, the measurement results of gamma-ray spectroscopy logging-while-drilling are mainly affected by multiple factors such as formation and non-formation. At present, there is no relevant complete patent.
[0045] To solve the above problems, the present invention proposes a method for collecting gamma energy spectrum while drilling, its energy spectrum correction method and system. The present invention solves the problem that the influence of well diameter, mud density, KCL concentration and barite content on measurement data is not considered simultaneously in the existing measurement methods. During the measurement while drilling, real-time gamma energy spectrum measurement is carried out on the measured well, and the measurement data of the gamma energy spectrum while drilling is divided into multi-level energies. Combining the actual data of the measured well in different dimensions, using a preset multi-dimensional energy spectrum correction model, multi-dimensional correction is performed on the energy spectrum count data at each level, so as to adjust the dimension based on the wellbore size, mud density, KCL concentration and barite content, and adjust the measurement result of the gamma energy spectrum while drilling. The present invention can effectively reduce the influence of the formation environment on the measurement result, make the logging instrument more truly reflect the formation information, and provide more accurate data guarantee for subsequent logging interpretation and geological steering results.
[0046] Embodiment 1
[0047] Figure 1 Schematic diagram of the steps of the correction method for adjusting the gamma energy spectrum measurement while drilling according to the embodiment of the present application. Figure 2 It is a schematic flow chart of the correction method for adjusting the gamma energy spectrum measurement while drilling according to the embodiment of the present application. The following combines Figure 1 and Figure 2 to describe the correction method of this embodiment in detail.
[0048] Step S110: Obtain the count statistical data of the multi-level energies of the measured gamma energy spectrum while drilling.
[0049] In one embodiment, the multi-level energy spectrum count data is five-energy spectrum count data.
[0050] In the embodiment of the present invention, the gamma ray energies released by potassium, uranium, and thorium are significantly different. Therefore, the measured gamma rays can be used as markers to separately identify and measure potassium, uranium, and thorium. Multi-level energy windows are used for data acquisition to establish the count statistical data of each energy window of the gamma energy spectrum logging tool while drilling.
[0051] In the embodiment of the present invention, when using the logging tool while drilling, after real-time acquisition of the gamma energy spectrum data while drilling during the logging while drilling process, five energy windows will be divided according to the energy levels of potassium, uranium, and thorium, and the gamma energy spectrum collected by the gamma energy spectrum measuring instrument while drilling will be energy-divided to obtain the count statistical data of five levels of energy, namely W 1 , W 2 , W 3 , W 4 and W 5 , so that in step S110, the multi-level energy spectrum count data (such as five-energy window count data) of these real-time measured gamma energy spectrum data while drilling is received.
[0052] Step S120: According to the multi-level energy spectrum counting data, combined with the actual data of the measured well in different dimensions, use the preset multi-dimensional energy spectrum correction model to perform multi-dimensional correction on the energy spectrum counting data of each level. In the embodiment of the present invention, the correction dimensions include: wellbore size, mud density, KCL concentration, and barite content.
[0053] In one embodiment, the multi-dimensional energy spectrum correction model is constructed in the following manner: According to the gamma energy spectrum data under different wellbore size conditions, analyze the influence of the well diameter on the change of the spectrum data, so as to obtain a well diameter correction expression for correcting the spectrum data in the wellbore size dimension; According to the gamma energy spectrum data under different mud density conditions, analyze the influence of the mud density on the change of the spectrum data, so as to obtain a mud density correction expression for correcting the spectrum data in the mud density dimension; According to the gamma energy spectrum data under different KCL content conditions in the mud, analyze the influence of the KCL content on the change of the spectrum data, so as to obtain a KCL content correction expression for correcting the spectrum data in the KCL content dimension; According to the gamma energy spectrum data under different barite content conditions in the mud, analyze the influence of the barite content on the change of the spectrum data, so as to obtain a barite content correction expression for correcting the spectrum data in the barite content dimension; Integrate the well diameter correction expression, mud density correction expression, KCL content correction expression, and barite content correction expression to establish a multi-dimensional energy spectrum correction model.
[0054] In one embodiment, according to the multi-level energy spectrum counting data of the gamma energy spectrum data of the standard calibration well under different wellbore size conditions, establish a well diameter correction factor chart representing the relationship between different well diameter conditions and the multi-level energy spectrum counting data, so as to obtain a well diameter correction expression. Among them, the well diameter correction expression is represented by the following formula:
[0055]
[0056] Among them, X′ n represents the theoretical value of the multi-level energy spectrum counting data, X n represents the multi-level energy spectrum counting data measured in the standard calibration well under different wellbore size conditions, r bh represents the wellbore size, r sonde represents the detector size, t represents the correlation coefficient related to the detector size, and k represents the correlation coefficient related to the wellbore size.
[0057] In an embodiment of the present invention, based on the actual data of the measured well, the wellbore size and detector size data of the standard calibration well are configured, and then the multi-level energy spectrum count data measured in the standard calibration well is obtained. Combining with the theoretical values of the preset multi-level energy spectrum count data, a wellbore diameter correction factor chart representing the relationship between different wellbore diameter conditions and the multi-level energy spectrum count data is established, and the correlation coefficient related to the wellbore size is solved using formula (1).
[0058] In one embodiment, a wellbore size correction factor chart representing the corresponding five-energy window count change rules under different wellbore sizes is established. Figure 3 This is an example chart of the wellbore size correction factor for the correction method for adjusting the gamma energy spectrum measurement while drilling in the embodiments of the present application. As Figure 3 shown, curve 1 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the wellbore size is 6 in and the instrument is centered; curve 2 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the wellbore size is 8.5 in and the instrument is centered; curve 3 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the wellbore size is 9.625 in and the instrument is centered; curve 4 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the wellbore size is 12.25 in and the instrument is centered. According to the wellbore size correction factor example chart, as the wellbore size gradually increases, the count rate of the gamma energy spectrum spectral data gradually decreases, but the shapes of curves 1, 2, 3, and 4 remain the same. Combining with the theoretical values of the preset multi-level energy spectrum count data, the wellbore diameter correction expression is determined.
[0059] In one embodiment, based on the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different mud density conditions, a mud density correction factor chart representing the relationship between different mud density conditions and the multi-level energy spectrum count data is established to obtain the mud density correction expression. Among them, the mud density correction expression is represented by the following formula:
[0060]
[0061] Among them, X′ n represents the theoretical value of the multi-level energy spectrum count data, X n represents the multi-level energy spectrum count data measured in the standard calibration well under different mud density conditions, μ represents the correlation parameter related to the mud density, and ρ mud represents the mud density.
[0062] In an embodiment of the present invention, based on the actual data of the measured well, the mud density data of the standard calibration well is configured, and then the multi-level energy spectrum count data measured in the standard calibration well is obtained. Combining with the theoretical values of the preset multi-level energy spectrum count data, a mud density correction factor chart representing the relationship between different mud density conditions and the multi-level energy spectrum count data is established, and the correlation coefficient related to the mud density is solved using formula (2).
[0063] In one embodiment, a mud density correction factor chart showing the corresponding change law of the five-energy window count under different mud densities is established. Figure 4 This is an example chart of the mud density correction factor for the correction method for adjusting the gamma energy spectrum measurement while drilling in the embodiments of the present application. As Figure 4 shown, curve 5 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the mud density is 1 kg / l; curve 6 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the mud density is 1.2 kg / l; curve 7 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the mud density is 1.4 kg / l; curve 8 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the mud density is 1.8 kg / l. According to the example chart of the mud density correction factor, as the mud density increases, the count rate of the gamma energy spectrum spectral data decreases, but the shapes of curves 5, 6, 7, and 8 remain the same. Combining with the theoretical values of the preset multi-level energy spectrum count data, the mud density correction expression is determined.
[0064] In one embodiment, based on the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different KCL content conditions in the mud, a KCL content correction factor chart representing the relationship between different KCL content conditions and the multi-level energy spectrum count data is established to obtain the KCL content correction expression. Among them, the KCL content correction expression is represented by the following formula:
[0065] X′ n =X n (aρ kcl 2 +bρ kcl +c) (3)
[0066] wherein, X′ n represents the theoretical value of the multi-level energy spectrum count data, X n represents the multi-level energy spectrum count data measured in the standard calibration well under different KCL content conditions, ρ kcl represents the KCL content in the mud, and a, b, and c respectively represent the correlation coefficients related to the KCL concentration.
[0067] In an embodiment of the present invention, based on the actual data of the measured well, the content of the KCL solution in the standard calibration well is configured, and then the multi-level energy spectrum count data measured in the standard calibration well is obtained. Combining with the theoretical values of the preset multi-level energy spectrum count data, a KCL content correction factor chart representing the relationship between different KCL content conditions and the multi-level energy spectrum count data is established, and the correlation coefficient related to the KCL concentration is solved using formula (3).
[0068] In one embodiment, a KCL concentration correction factor chart representing the variation law of the corresponding five-energy window counts under different KCL concentrations is established. Figure 5 This is an example chart of the KCL content correction factor for the correction method used to adjust the gamma energy spectrum measurement while drilling in the embodiments of the present application. As Figure 5 shown, curve 9 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the KCL solution concentration is 20%; curve 10 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the KCL solution concentration is 15%; curve 11 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the KCL solution concentration is 10%; curve 12 represents the spectral data measured by the gamma energy spectrum measurement while drilling when the KCL solution concentration is 5%. According to the example chart of the KCL content correction factor, as the content of the KCL solution increases, the difference in spectral data becomes larger and larger, resulting in an abnormal potassium peak, while the uranium and thorium contents are too low, thus causing the measurement result to be distorted and unable to truly reflect the formation characteristics. Combining with the theoretical values of the preset multi-level energy spectrum count data, the KCL content correction expression is determined.
[0069] In one embodiment, according to the multi-level energy spectrum count data of the gamma energy spectrum data of the standard calibration well under different barite content conditions in the mud, a barite content correction factor chart representing the relationship between different barite content conditions and the multi-level energy spectrum count data is established to obtain the barite content correction expression. Among them, the barite content correction expression is represented by the following formula:
[0070] X′ n =X n (a′ρ b 2 +b′ρ b +c′) (4)
[0071] wherein, X′ n represents the theoretical value of the multi-level energy spectrum count data, X n represents the multi-level energy spectrum count data measured in the standard calibration well under different barite content conditions, ρ kcl represents the barite content in the mud, and a′, b′, and c′ respectively represent the correlation coefficients related to the barite content.
[0072] In an embodiment of the present invention, based on the actual data of the measured well, the barite content of the standard calibration well is configured, and then the multi-level energy spectrum count data measured in the standard calibration well is obtained. Combining with the theoretical values of the preset multi-level energy spectrum count data, a barite content correction factor chart representing the relationship between different barite content conditions and the multi-level energy spectrum count data is established, and the correlation coefficient related to the barite content is solved using formula (4).
[0073] Furthermore, by integrating the well diameter correction expression, the mud density correction expression, the KCL content correction expression, and the barite content correction expression, a multi-dimensional energy spectrum correction model is established. Based on the multi-level energy spectrum count data of the measured well measured by the gamma ray energy spectrum measuring instrument while drilling, combined with the multi-dimensional energy spectrum correction model, the corrected multi-dimensional energy spectrum count data is determined. Among them, the multi-dimensional energy spectrum correction model is represented by the following formula:
[0074] W′ (r) =W (r) sd[1-e mn (5)
[0075] Where m represents the correction coefficient for the well diameter dimension, m = k(r bh -r sonde )+t, r bh represents the wellbore size of the measured well, r sonde represents the detector size of the measured well, t and k respectively represent the chart-related coefficients in the well diameter correction expression, n represents the correction coefficient for the mud density dimension, n = -μρ mud , μ represents the chart-related coefficient in the mud density correction expression, ρ mud represents the mud density of the measured well, s represents the correction coefficient for the KCL concentration dimension, s = (aρ kcl 2 +bρ kcl +c), ρ kcl represents the KCL content in the mud of the measured well, a, b, and c respectively represent the chart-related coefficients in the KCL content correction expression, d represents the correction coefficient for the barite content dimension, d = (a′ρ b 2 +b′ρ b +c′), ρ kcl represents the barite content in the mud of the measured well, a′, b′, and c′ respectively represent the chart-related coefficients in the barite content correction expression, W (r) represents the multi-level energy spectrum count data before correction, and W′ (r) represents the corrected multi-dimensional energy spectrum count data.
[0076] In the embodiment of the present invention, based on the multi-dimensional energy spectrum correction model described in formula (5), the counting statistical data W of the five-level energies of the measured well 1 、W 2 、W 3 、W 4 and W 5 are respectively subjected to multi-dimensional correction to calculate the true potassium, uranium, and thorium contents by using the corrected five-energy spectrum counting data. The correction dimensions include: wellbore size, mud density, KCL concentration, and barite content. Thus, by using the above steps S110 to S130, the corrected counting data of the five-level energies are obtained, which are W' 1 、W' 2 、W' 3 、W' 4 、W' 5 .
[0077] Embodiment 2
[0078] Based on the correction method for adjusting the gamma energy spectrum measurement while drilling described in the above embodiment 1, the present invention also provides a correction system for adjusting the gamma energy spectrum measurement while drilling. This system is used to implement the correction method for adjusting the gamma energy spectrum measurement while drilling described in the above embodiment 1.
[0079] Figure 6 is a schematic structural diagram of the correction system for adjusting the gamma energy spectrum measurement while drilling in the embodiment of the present application. As Figure 6 shown, the system described in the embodiment of the present invention includes: a full-spectrum data input module 601 and a correction processing module 602.
[0080] Specifically, the full-spectrum data input module 601 is implemented according to the method described in the above step S110, and is configured to obtain the counting statistical data of the multi-level energies of the measured gamma energy spectrum while drilling; the correction processing module 602 is implemented according to the method described in the above step S120, and is configured to respectively perform multi-dimensional correction on the counting data of each level of the energy spectrum by using the preset multi-dimensional energy spectrum correction model in combination with the actual data of the measured well in different dimensions. The correction dimensions include: wellbore size, mud density, KCL concentration, and barite content.
[0081] Embodiment 3
[0082] Based on the correction method for adjusting the gamma energy spectrum measurement while drilling described in the above embodiment 1, the present invention also provides a method for collecting gamma energy spectrum while drilling. Figure 7 is a schematic diagram of the steps of the method for collecting gamma energy spectrum while drilling in the embodiment of the present application.
[0083] Step S710: During the measurement while drilling, perform real-time gamma energy spectrum measurement on the measured well.
[0084] In the embodiment of the present invention, the gamma energy spectrum logging-while-drilling tool collects the gamma energy spectrum measurement data of the measured well in real time.
[0085] Step S720: Divide the gamma energy spectrum measurement data obtained while drilling into multiple energy levels according to different energy levels, and perform statistical counting on the spectrum data at different energy levels.
[0086] In the embodiment of the present invention, five energy windows are divided according to the energy levels of potassium, uranium, and thorium, and the gamma energy spectrum collected by the gamma energy spectrum logging-while-drilling tool is divided into energy levels and counted to obtain the counting statistical data of five levels of energy, which are W 1 、W 2 、W 3 、W 4 and W 5 .
[0087] Step S730: Correct the multi-level energy spectrum counting data respectively.
[0088] In the embodiment of the present invention, based on the correction method for adjusting the gamma energy spectrum measurement while drilling described in Embodiment 1, the multi-level energy spectrum counting data is corrected in multiple dimensions. The correction dimensions include: borehole size, mud density, KCL concentration, and barite content, to obtain the corrected counting data of five levels of energy, which are W' 1 、W' 2 、W' 3 、W' 4 、W' 5 .
[0089] Step S740: Perform weighted matrix operation on the corrected multi-level energy spectrum counting data to obtain the true potassium, uranium, and thorium contents.
[0090] In the embodiment of the present invention, weighted least squares method operation is performed on the corrected counting data of five levels of energy, and then the true potassium, uranium, and thorium contents of the formation are obtained.
[0091] The present invention provides a method for collecting gamma energy spectrum while drilling, as well as an energy spectrum correction method and system therefor. The present invention solves the problem that the existing measurement methods do not simultaneously consider the influence of well diameter, mud density, KCL concentration, and barite content on the measurement data. During the measurement while drilling, real-time gamma energy spectrum measurement is performed on the measured well, and the measurement data of the gamma energy spectrum while drilling is divided into multiple levels of energy. Combining the actual data of the measured well in different dimensions, using a preset multi-dimensional energy spectrum correction model, multi-dimensional correction is performed on the energy spectrum count data at each level, so as to adjust the dimension based on the wellbore size, mud density, KCL concentration, and barite content, and adjust the measurement result of the gamma energy spectrum while drilling. The present invention can effectively reduce the influence of the formation environment on the measurement result, enable the logging instrument to more truly reflect the formation information, and provide more accurate data guarantee for subsequent logging interpretation and geological steering results.
[0092] As described above, only the preferred specific embodiments of the present invention are given, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
[0093] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0094] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0095] It should be understood that the embodiments disclosed by the present invention are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean to limit.
[0096] As used in the specification, the phrase "an embodiment" or "embodiments" means that the specific features, structures, or characteristics described in connection with the embodiments are included in at least one embodiment of the present invention. Thus, the phrase "an embodiment" or "embodiments" that appears throughout the specification does not necessarily refer to the same embodiment.
[0097] Although the embodiments disclosed in the present invention are as described above, the above content is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.
Claims
1. A correction method for adjusting gamma spectroscopy while drilling, characterized in that: include: Obtaining counting statistics of multi-level energies of the measured while-drilling gamma spectrum; According to the multi-level energy spectrum counting data, combined with the actual data of the measured wells in different dimensions, the preset multi-dimensional energy spectrum correction model is used to perform multi-dimensional correction on the energy spectrum counting data at each level. The correction dimensions include: wellbore size, mud density, KCL concentration and barite content.
2. The calibration method according to claim 1, characterized in that: The multi-dimensional energy spectrum correction model is constructed in the following manner: According to the gamma spectrum data under different borehole size conditions, the influence of wellbore diameter on the change of spectrum data is analyzed, so as to obtain the wellbore diameter correction expression used to correct the spectrum data for the borehole size dimension; According to the gamma spectrum data under different mud density conditions, the influence of mud density on the spectrum data change is analyzed, so as to obtain the mud density correction expression used to correct the spectrum data for mud density dimension; According to the gamma spectrum data under different KCL content conditions in the mud, the influence of KCL content on the spectrum data change is analyzed, so as to obtain the KCL content correction expression for KCL content dimension correction of the spectrum data; According to the gamma spectrum data under different barite contents in the mud, the influence of barite content on the change of spectrum data is analyzed, so as to obtain the barite content correction expression for correcting the spectrum data for barite content dimension; The multi-dimensional energy spectrum correction model is established by integrating the wellbore correction expression, mud density correction expression, KCL content correction expression and barite content correction expression.
3. The calibration method according to claim 2, characterized in that: The process of constructing the caliper correction expression includes: According to the multi-level energy spectrum counting data of the gamma energy spectrum data of the standard calibration well under different borehole size conditions, a well diameter correction factor plate characterizing the relationship between different well diameter conditions and the multi-level energy spectrum counting data is established to obtain the well diameter correction expression, wherein the well diameter correction expression is expressed by the following formula: In the formula, X′ n represents the theoretical value of multi-level energy spectrum counting data, X n represents the multi-level energy spectrum counting data measured in the standard scale well under different wellbore size conditions, r bh represents the wellbore size, r sonde represents the detector size, t represents the correlation coefficient related to the detector size, and k represents the correlation coefficient related to the wellbore size.
4. The calibration method according to claim 2 or 3, characterized in that: The process of constructing the mud density correction expression includes: According to the multi-level energy spectrum counting data of the gamma spectrum data of the standard calibration well under different mud density conditions, a mud density correction factor chart characterizing the relationship between different mud density conditions and the multi-level energy spectrum counting data is established to obtain the mud density correction expression, wherein the mud density correction expression is expressed by the following formula: In the formula, X′ n represents the theoretical value of multi-level energy spectrum counting data, X n represents the multi-level energy spectrum counting data measured in the standard scale well under different mud density conditions, μ represents the relevant parameters related to mud density, ρ mud Indicates mud density.
5. The calibration method according to any one of claims 2 to 4, characterized in that: The process of constructing the KCL content correction expression includes: According to the multi-level energy spectrum counting data of the gamma energy spectrum data of the standard calibration well under the conditions of KCL content in different muds, a KCL content correction factor plate characterizing the relationship between different KCL content conditions and the multi-level energy spectrum counting data is established to obtain the KCL content correction expression, wherein the KCL content correction expression is expressed by the following formula: X′ n =X n (aρ kcl 2 +bρ kcl +c) In the formula, X′ n represents the theoretical value of multi-level energy spectrum counting data, X n represents the multi-level energy spectrum counting data measured in the standard calibration well under different KCL content conditions, ρ kcl represents the KCL content in the mud, and a, b, and c represent the correlation coefficients related to the KCL concentration.
6. The calibration method according to any one of claims 2 to 5, characterized in that: The process of constructing the barite content correction expression includes: According to the multi-level energy spectrum counting data of gamma energy spectrum data of standard calibration wells under different barite content conditions in mud, a barite content correction factor chart characterizing the relationship between different barite content conditions and multi-level energy spectrum counting data is established to obtain the barite content correction expression, wherein the barite content correction expression is expressed by the following formula: X′ n =X n (a′ρ b 2 +b′ρ b +c′) In the formula, X′ n represents the theoretical value of multi-level energy spectrum counting data, X n represents the multi-level energy spectrum counting data measured in the standard calibration well under different barite content conditions, ρ kcl represents the barite content in the mud, and a′, b′, and c′ represent the correlation coefficients related to the barite content, respectively.
7. The calibration method according to any one of claims 2 to 6, characterized in that: The multi-dimensional energy spectrum correction model is expressed by the following expression: IN' (r) =In (r) sd[1-e mn ] Where m represents the correction factor for the wellbore dimension, m = k(r bh -r sonde )+t,r bh represents the borehole size of the measured well, r sonde represents the detector size of the measured well, t and k represent the plate correlation coefficients in the wellbore correction expression, n represents the correction coefficient for the mud density dimension, n = -μρ mud , μ represents the plate correlation coefficient in the mud density correction expression, ρ mud represents the mud density of the measured well, s represents the correction coefficient for the KCL concentration dimension, s = (aρ kcl 2 +bρ kcl +c),ρ kcl represents the KCL content in the mud of the measured well, a, b, c represent the plate correlation coefficients in the KCL content correction expression, d represents the correction coefficient for the barite content dimension, d = (a′ρ b 2 +b′ρ b +c′),ρ kcl represents the barite content in the mud of the measured well, c′, b′, c′ respectively represent the plate correlation coefficients in the barite content correction expression, W (r) represents the multi-level energy spectrum counting data before correction, W′ (r) Represents the corrected multi-dimensional energy spectrum counting data.
8. The calibration method according to any one of claims 1 to 7, characterized in that: The multi-level energy spectrum counting data is five-level energy spectrum counting data.
9. A correction system for adjusting gamma spectroscopy while drilling, characterized in that: The correction system comprises: A full spectrum data input module configured to obtain counting statistics of multi-level energies of a measured while-drilling gamma energy spectrum; The correction processing module performs multi-dimensional correction on each level of energy spectrum counting data based on the multi-level energy spectrum counting data and the actual data of the measured wells in different dimensions using a preset multi-dimensional energy spectrum correction model. The correction dimensions include: wellbore size, mud density, KCL concentration and barite content.
10. A method for collecting gamma ray spectrum while drilling, characterized in that: include: During the measurement while drilling process, real-time gamma spectrum measurement is performed on the measured wells; According to different energy levels, the gamma ray spectrum measurement data while drilling is divided into multiple energy levels and the spectrum data at different energy levels are statistically counted; According to the correction method described in any one of claims 1 to 8, the multi-level energy spectrum counting data are corrected respectively; The corrected multi-level energy spectrum counting data are subjected to weighted matrix operations to obtain the true potassium, uranium and thorium contents.