A method and system for correcting core nuclear magnetic resonance measurements in a high-altitude environment
By constructing a total porosity and T2 spectrum morphology correction model in a high-altitude environment, and combining controlled-temperature experiments and real-time correction technology, the problem of low accuracy in core nuclear magnetic resonance measurements was solved, and accurate correction of core nuclear magnetic resonance measurement results was achieved, thus improving measurement precision and accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINESE ACAD OF GEOLOGICAL SCI
- Filing Date
- 2026-04-16
- Publication Date
- 2026-05-29
AI Technical Summary
In high-altitude environments, the accuracy of core nuclear magnetic resonance measurements is low, and the porosity and T2 spectrum morphology deviate significantly. Existing technologies lack dedicated calibration models for complex temperature environments at high altitudes, resulting in significant discrepancies between laboratory baseline data and field measured data, which affects the accuracy and reliability of reservoir evaluation.
By acquiring multiple core sample sets, benchmark nuclear magnetic resonance measurements were performed at standard laboratory temperatures. Multiple total porosity correction models and T2 spectrum morphology correction models were constructed. Combined with temperature-controlled variable-temperature experiments, nuclear magnetic resonance data were collected, correction models were constructed, and core nuclear magnetic parameters were corrected in real time in the field.
It achieves temperature-adaptive real-time correction of core nuclear magnetic resonance measurement results in high-altitude field environments, improves the accuracy of total porosity and T2 spectrum morphology measurements, and ensures the accuracy and reliability of measurement results.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of nuclear magnetic resonance measurement and correction technology, specifically to a method and system for core nuclear magnetic resonance measurement and correction in high-altitude environments. Background Technology
[0002] Nuclear magnetic resonance (NMR) technology has become a core tool for core property analysis in oil and gas exploration and development, enabling non-destructive acquisition of key reservoir parameters such as total porosity and T2 spectrum morphology. However, during field measurements at high altitudes, the drastic changes in temperature and pressure experienced by the core after extraction from the ground significantly alter the occurrence state, relaxation characteristics, and NMR response features of the pore fluids. This leads to significant discrepancies between laboratory baseline data and field measurements. Existing technologies largely rely on isothermal laboratory measurements and lack dedicated calibration models for the complex temperature environment at high altitudes. Consequently, it is difficult to achieve real-time and accurate calibration of total porosity and T2 spectrum morphology, severely impacting the accuracy and reliability of reservoir evaluation in high-altitude areas.
[0003] The existing technology addresses the technical problems of low accuracy and large deviation between porosity and T2 spectrum morphology in core nuclear magnetic resonance measurements under the influence of high-altitude ambient temperature. Summary of the Invention
[0004] This application provides a core nuclear magnetic resonance measurement correction method and system for high-altitude environments, which is used to address the technical problems of low accuracy and large deviation between porosity and T2 spectrum morphology in core nuclear magnetic resonance measurements under the influence of temperature in high-altitude environments in the prior art.
[0005] In view of the above problems, this application provides a method and system for core nuclear magnetic resonance measurement correction in high-altitude environments.
[0006] The first aspect of this application provides a method for correcting core magnetic resonance measurements in high-altitude environments, the method comprising:
[0007] Multiple core sample sets from multiple work areas were acquired, and sample pretreatment was performed. Reference NMR measurements were conducted at standard laboratory temperatures to obtain multiple reference NMR parameters. The pretreated core sample sets were then placed in a temperature-controlled environment, and NMR experiments were conducted under variable temperature conditions according to a preset temperature sequence. NMR data were collected at each temperature point to obtain multiple sets of experimental NMR parameter sequences. Based on these sets of experimental NMR parameter sequences and the reference NMR parameters, NMR correction analysis was performed to construct multiple total porosity correction models and multiple T2 spectral morphology correction models. During field NMR measurements, real-time ambient temperature and real-time core sample type characteristics were simultaneously acquired. Based on these real-time core sample type characteristics, multiple total porosity correction models and multiple T2 spectral morphology correction models were matched to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. Real-time correction of the measurement results was performed to obtain corrected real-time NMR parameters.
[0008] A second aspect of this application provides a core nuclear magnetic resonance measurement correction system for high-altitude environments, the system comprising:
[0009] The module for acquiring reference NMR parameters is used to acquire multiple core sample sets from multiple work areas, perform sample pretreatment, and conduct reference NMR measurements at standard laboratory temperatures to acquire multiple reference NMR parameters. The module for acquiring experimental NMR parameter sequence sets is used to place the pretreated core sample sets in a temperature-controlled environment, conduct NMR experiments under variable temperature conditions according to a preset temperature sequence, collect NMR data at each temperature point, and obtain multiple sets of experimental NMR parameter sequences. The module for constructing calibration models is used to perform NMR calibration analysis based on the multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, constructing multiple total porosity calibration models and multiple T2 spectral morphology calibration models. The module for acquiring real-time calibration NMR parameters is used to simultaneously acquire real-time ambient temperature and real-time core sample type characteristics during core NMR measurements in the field, match multiple total porosity calibration models and multiple T2 spectral morphology calibration models based on the real-time core sample type characteristics, obtain a matched total porosity calibration model and a matched T2 spectral morphology calibration model, perform real-time calibration of the measurement results, and obtain calibrated real-time NMR parameters.
[0010] One or more technical solutions provided in this application have at least the following technical effects or advantages:
[0011] Multiple core sample sets from various work areas were acquired, sample pretreatment was performed, and baseline NMR measurements were conducted at standard laboratory temperatures to obtain multiple baseline NMR parameters. NMR experiments were then conducted under variable temperature conditions according to a preset temperature sequence, collecting NMR data at various temperature points to obtain multiple sets of experimental NMR parameter sequences. Multiple total porosity correction models and multiple T2 spectral morphology correction models were constructed. During core NMR measurements in the field, real-time ambient temperature and real-time core sample type characteristics were simultaneously acquired. Based on these real-time core sample type characteristics, multiple total porosity correction models and multiple T2 spectral morphology correction models were matched to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. Real-time correction of the measurement results was then performed to obtain corrected real-time NMR parameters. This method achieves temperature-adaptive real-time correction of core NMR measurement results in high-altitude field environments, effectively improving the accuracy of total porosity and T2 spectral morphology measurements. Attached Figure Description
[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0013] Figure 1 A schematic flowchart of a core nuclear magnetic resonance measurement correction method in a high-altitude environment is provided for embodiments of this application.
[0014] Figure 2 This is a schematic diagram of a core magnetic resonance measurement and correction system for high-altitude environments, provided as an embodiment of this application.
[0015] Figure labeling: Module 10 for acquiring baseline NMR parameters, Module 20 for acquiring experimental NMR parameter sequence set, Module 30 for constructing calibration model, and Module 40 for acquiring calibration real-time NMR parameters. Detailed Implementation
[0016] This application provides a method and system for correcting core nuclear magnetic resonance measurements in high-altitude environments, which addresses the technical problems of low accuracy and large deviations in porosity and T2 spectrum morphology in existing technologies under the influence of temperature in high-altitude environments.
[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0018] Example 1, as Figure 1 As shown, this application provides a method for correcting core nuclear magnetic resonance measurements in high-altitude environments, the method comprising:
[0019] Step S100: Obtain multiple core sample sets from multiple work areas, perform sample pretreatment, and conduct benchmark nuclear magnetic resonance measurements at standard laboratory temperature to obtain multiple benchmark nuclear magnetic parameters.
[0020] Specifically, core samples from multiple work areas are first collected and integrated into multiple core sample sets. Standardized sample pretreatment is performed on all core samples to eliminate the influence of impurities, gas content in pores, and other interference factors on the subsequent nuclear magnetic resonance (NMR) measurement results. The pretreated core samples are then placed in a standard laboratory temperature environment to conduct benchmark NMR measurements, accurately obtaining multiple benchmark NMR parameters. Each benchmark NMR parameter includes a benchmark T2 spectrum and a benchmark total porosity, thus establishing a unified and standardized reference data system for subsequent NMR measurement calibration in high-altitude environments.
[0021] Step S200: Place the pretreated core sample set in a temperature-controlled environment and conduct nuclear magnetic resonance experiments under variable temperature conditions according to the preset temperature sequence. Collect nuclear magnetic resonance data at each temperature point to obtain a set of multiple experimental nuclear magnetic parameter sequences.
[0022] Specifically, multiple pre-processed core samples were placed in a temperature-controlled professional experimental chamber. Combined with the actual temperature conditions of the high-altitude, extremely cold environment, nuclear magnetic resonance (NMR) experiments were conducted under variable temperature conditions according to a preset temperature sequence including 10℃, 0℃, -10℃, -25℃, and -40℃. The entire process strictly followed a standardized cyclical operation procedure of cooling-temperature stabilization-NMR measurement-heating. NMR-related data were accurately collected at each temperature node in the sequence, and the experimental T2 spectrum and experimental baseline total porosity were recorded in detail for each temperature point. Simultaneously, experimental data collection from core sample groups with different lithologies and pore structures was also considered. The experimental data from all core samples at each temperature point were then organized and integrated according to temperature sequence and sample type, ultimately forming a set of multiple experimental NMR parameter sequences that accurately reflect the evolution of the correlation between temperature and NMR parameters across the entire temperature gradient from positive to extremely low temperatures.
[0023] Step S300: Based on the multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, perform NMR correction analysis to construct multiple total porosity correction models and multiple T2 spectral morphology correction models.
[0024] Specifically, a systematic NMR correction analysis was conducted using multiple sets of experimental NMR parameter sequences and multiple benchmark NMR parameters as the core analytical basis. First, a total porosity change rate analysis was performed based on the two types of data, and multiple sets of total porosity change rate sequences were calculated and obtained. Then, correction coefficient analysis was performed on each set of change rate sequences to obtain multiple sets of correction coefficient sequences. After consistency screening of the correction coefficients, multiple target correction coefficient-temperature mapping relationship models were obtained, and multiple total porosity correction models were constructed based on these models. At the same time, a T2 spectrum morphology shift characteristic analysis was conducted based on multiple sets of experimental NMR parameter sequences and multiple benchmark NMR parameters to explore the morphological change law of T2 spectrum under the influence of temperature. Based on the analysis results, multiple T2 spectrum morphology correction models were constructed, forming a dual correction model system of total porosity and T2 spectrum morphology adapted to different core characteristics, providing model support for the accurate correction of NMR measurement results in the field.
[0025] Step S400: When performing core NMR measurements in the field, simultaneously acquire real-time ambient temperature and real-time core sample type characteristics. Based on the real-time core sample type characteristics, match multiple total porosity correction models and multiple T2 spectral morphology correction models to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. Perform real-time correction of the measurement results to obtain the corrected real-time NMR parameters.
[0026] Specifically, when conducting core NMR measurements at high altitudes in the field, the system simultaneously acquires real-time ambient temperature and core sample type characteristics using environmental sensing equipment and core feature recognition methods. Using these real-time core sample type characteristics as a precise matching index, the system directionally matches the corresponding total porosity correction model and T2 spectral morphology correction model from the pre-built model library. Real-time ambient temperature is then substituted into both matching models as the core variable. Model embedding is used to perform real-time correction processing on the raw NMR data from the field measurements, including total porosity numerical correction and T2 spectral morphology reconstruction. Through iterative data computation, the system completes the full-dimensional correction of the original measurement results, ultimately obtaining corrected real-time NMR parameters that accurately reflect the actual porosity characteristics of the formation. This achieves precise and dynamic correction of core NMR measurement results under uncontrolled temperature conditions at high altitudes.
[0027] In one possible implementation, step S300 further includes:
[0028] Step S310: Each of the plurality of reference NMR parameters includes a reference T2 spectrum and a reference total porosity.
[0029] Specifically, the dimensions and contents of multiple benchmark NMR parameters obtained from benchmark NMR measurements conducted in the previous stage under standard laboratory temperatures were defined and standardized. It was clarified that each benchmark NMR parameter consists of two core parameters: benchmark T2 spectrum and benchmark total porosity. The benchmark T2 spectrum accurately characterizes the transverse relaxation time distribution characteristics of core samples under standard conditions, while the benchmark total porosity reflects the benchmark value of total porosity of core samples under standard conditions. Together, they form a standardized NMR parameter benchmark system, providing a unified and clear reference benchmark for subsequent analysis of porosity change rate and T2 spectrum morphological shift characteristics based on experimental NMR parameters. This ensures the accuracy and comparability of subsequent NMR correction analysis and correction model construction.
[0030] In one possible implementation, step S200 further includes:
[0031] Step S210: Place the multiple core samples in a temperature-controlled environmental chamber and perform cooling-constant temperature-measurement-heating at different temperature points according to a preset temperature sequence.
[0032] Step S220: Perform nuclear magnetic resonance measurements at each temperature point, record the experimental T2 spectrum and the experimental baseline total porosity, and obtain a set of multiple experimental nuclear magnetic parameter sequences.
[0033] Specifically, after pretreatment, multiple core samples were individually packaged and placed in temperature-controlled environmental chambers to ensure that each core sample was in an independent and precisely temperature-controlled experimental environment, avoiding experimental interference between samples. Subsequently, based on the actual temperature change characteristics of the high-altitude environment, a corresponding preset temperature sequence was set. Through the programmed temperature control function of the environmental chamber, each core sample was subjected to a standardized operation of cooling, isothermal control, measurement, and heating in sequence. During the isothermal control stage, the temperature was stabilized to the preset value before proceeding to the subsequent measurement stage, ensuring that the experimental conditions at each temperature point were uniform and controllable, laying the experimental foundation for the subsequent accurate acquisition of nuclear magnetic resonance data at each temperature point.
[0034] After achieving constant temperature stabilization at each temperature point in the preset temperature sequence, standardized nuclear magnetic resonance (NMR) measurements were performed on each core sample in the temperature-controlled chamber. The experimental T2 spectrum and experimental baseline total porosity of each core sample at the corresponding temperature point were accurately collected and recorded to ensure that each set of data corresponds precisely to the temperature point and the core sample. Subsequently, the NMR measurement data of all core samples at different temperature points were systematically integrated and orderly collected according to sample category and temperature sequence, ultimately forming a set of multiple experimental NMR parameter sequences that can fully reflect the evolution of core NMR parameters under temperature gradient changes.
[0035] In one possible implementation, step S300 further includes:
[0036] Step S320: Perform a mapping total porosity change rate analysis based on multiple sets of experimental NMR parameter sequences and multiple benchmark NMR parameters to obtain multiple sets of total porosity change rate sequences.
[0037] Step S330: Combine the multiple sets of total porosity change rate sequences for correction analysis to construct multiple total porosity correction models.
[0038] Step S340: Based on multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, perform mapping T2 spectrum morphology shift feature analysis and construct multiple T2 spectrum morphology correction models.
[0039] Specifically, the experimental baseline total porosity of each core sample at each temperature point in a preset temperature sequence from multiple sets of experimental NMR parameter sequences, and the baseline total porosity of the same batch of core samples from multiple baseline NMR parameters are used as two sets of core data to conduct quantitative analysis and calculation of the mapped total porosity change rate. First, the experimental baseline total porosity of the same core sample is matched one-to-one with the baseline total porosity. Using the baseline total porosity as the benchmark value, the total porosity change rate of each core sample at different temperature points is calculated using the formula: total porosity change rate = experimental baseline total porosity / baseline total porosity. Then, the core samples are grouped according to their category and work area attributes. The total porosity change rate values of the core samples in each group are arranged in order according to the temperature of the preset temperature sequence to form a total porosity change rate sequence for a single sample / group. Finally, all the grouped and categorized sequences are integrated and collected to obtain a set of multiple total porosity change rate sequences that can accurately reflect the porosity change law under different cores and different temperature gradients.
[0040] A full-process calibration analysis was conducted using multiple sets of total porosity change rate sequences as the core data foundation. First, calibration coefficient analysis was performed on each sequence set, and multiple sets of calibration coefficient sequences corresponding to temperature gradients were obtained through quantitative calculation. Then, a consistency screening of calibration coefficient sequences was implemented. First, a set of calibration coefficient-temperature mapping point sequences was constructed with temperature as the horizontal axis and calibration coefficient as the vertical axis. An initial consistency screening line passing through the origin and matching the mean of the vertical coordinate of the mapping points was set. The screening direction was determined by counting the number of mapping points above and below the line, and the line was iteratively moved. The number of mapping points that met the preset distance threshold before and after the iteration was compared to determine whether to replace the line, until multiple target calibration coefficient-temperature mapping relationship models were obtained. Finally, based on these target mapping relationship models and combined with the temperature characteristics of high-altitude environment and the differences in core sample types, multiple total porosity calibration models adapted to different work areas and different core characteristics were constructed to achieve accurate calibration of the total porosity measurement results of core nuclear magnetic resonance at different temperatures.
[0041] Using experimental T2 spectra of core samples at different temperature points from multiple sets of experimental NMR parameter sequences as core comparison data, and benchmark T2 spectra of corresponding core samples from multiple benchmark NMR parameters as core data, a systematic analysis of T2 spectrum morphological shift characteristics was conducted. The morphological differences between experimental T2 spectra and benchmark T2 spectra of the same core sample at each temperature point were compared one by one. Key morphological shift characteristics, such as peak position shift, peak amplitude change, T2 relaxation time distribution interval change, and spectral curve distortion, were accurately extracted. Simultaneously, the influence and variation patterns of different temperature gradients on various morphological shift characteristics were quantitatively analyzed. The shift characteristics were classified and grouped according to the differences in core sample type and work area attributes. Based on the temperature-T2 spectrum morphological shift correlation obtained from the above analysis, feature mapping and morphological inversion models were constructed for different core characteristics and different temperature ranges. By fitting the correlation between temperature and various morphological indicators of the T2 spectrum through the models, multiple T2 spectrum morphological correction models were finally formed, capable of morphological correction and restoration of high-altitude field-measured T2 spectra based on real-time ambient temperature, achieving accurate correction of T2 spectrum morphological distortion caused by low temperature.
[0042] In one possible implementation, step S330 further includes:
[0043] Step S331: Perform correction coefficient analysis on the multiple sets of total porosity change rate sequences to obtain multiple sets of correction coefficient sequences.
[0044] Step S332: Perform consistency screening on the multiple sets of correction coefficient sequences to obtain multiple target correction coefficient-temperature mapping relationship models.
[0045] Step S333: Based on the multiple target correction coefficient-temperature mapping relationship model, construct the multiple total porosity correction models.
[0046] Specifically, using multiple sets of total porosity change rate sequences as the core data basis, a systematic correction coefficient analysis was independently conducted for each set of total porosity change rate sequences corresponding to different work areas and different core sample types. First, the quantitative correlation logic between the correction coefficient and the total porosity change rate was clarified. Using the baseline total porosity at standard laboratory temperature as the true reference value, the total porosity change rate calculated at each temperature point was used as the core calculation factor. Through the calculation formula of correction coefficient = 1 / total porosity change rate, the total porosity corresponding to each temperature gradient in each set of sequences was analyzed. The rate of change was converted one by one to obtain the NMR total porosity correction coefficient for the corresponding core sample at each temperature point. This coefficient is used to correct the measured porosity deviation at the corresponding temperature point under high-altitude environment. Then, the correction coefficients obtained from the same work area and the same core type were arranged in an orderly manner according to the temperature order of the preset temperature sequence to form a single group of correction coefficient sequences. Finally, the correction coefficient sequences corresponding to all different work areas and different core types were integrated and collected to obtain a set of multiple correction coefficient sequences that can accurately reflect the one-to-one correspondence between temperature and correction coefficient.
[0047] First, using temperature as the x-axis and correction coefficient as the y-axis, multiple sets of correction coefficient-temperature mapping point sequences are constructed based on the corresponding temperature and correction coefficient data in each set of correction coefficient sequences. Then, for each set of mapping point sequences, an initial consistency filtering line is set, passing through the origin of the coordinate axis and matching the mean y-coordinate of the mapping points in that set. Next, the number of upper mapping points above the initial line and the number of lower mapping points below it are counted. The filtering direction is determined based on the number comparison: if the number of upper mapping points is greater than or equal to the number of lower mapping points, the line is moved upwards; otherwise, it is moved downwards. This results in an iterative consistency filtering line. Subsequently, the number of mapping points in the set whose distances to the iterative line and the initial line meet a preset distance threshold is counted, yielding the iterative mapping point count and the initial mapping point count. If the iterative count is greater than or equal to the initial count, the initial line is replaced with the iterative line, and iteration continues in the original direction. If the iterative count is less than the initial count, iteration stops, and the final filtering line is used as the adaptation model for that set. After filtering all sets of mapping point sequences in this way, multiple target correction coefficient-temperature mapping relationship models are finally obtained, achieving a precise correlation between the correction coefficient and temperature.
[0048] The target correction coefficient-temperature mapping relationship model was adapted to different scenarios. The linear correlation between temperature and correction coefficient in the model was combined with the calculation logic of total porosity measured in the field. The core correction formula was defined as: total porosity measured in the field × corresponding temperature correction coefficient = corrected true total porosity. Then, the correction coefficient parameters in the model were finely adjusted and optimized according to the lithological differences and pore structure characteristics of different work areas, so that the model could better fit the actual measurement needs of each area. Subsequently, the optimized target correction coefficient-temperature mapping relationship model and the core correction formula were integrated and encapsulated to construct independent total porosity correction models adapted to different work areas and different core sample types. Each model can automatically match the corresponding correction coefficient and complete the accurate correction of total porosity based on the input real-time ambient temperature in the field. Finally, a system of multiple total porosity correction models covering multiple scenarios and types was formed.
[0049] In one possible implementation, step S332 further includes:
[0050] Using temperature as the horizontal axis and correction coefficient as the vertical axis, multiple sets of correction coefficient-temperature mapping point sequences are constructed based on the multiple sets of correction coefficient sequences.
[0051] Multiple straight lines passing through the origin of the coordinate axis and corresponding to the mean of the ordinate of the mapping points in the set of multiple correction coefficient-temperature mapping points are used as multiple initial consistency screening lines.
[0052] Based on the multiple initial consistency screening lines, the multiple sets of correction coefficient-temperature mapping point sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping relationship models.
[0053] Specifically, a two-dimensional rectangular coordinate system is established with temperature as the horizontal axis and correction coefficient as the vertical axis. The temperature data and correction coefficient data corresponding to each set of multiple correction coefficient sequence sets are plotted in this coordinate system according to a one-to-one mapping relationship, forming multiple correction coefficient-temperature mapping point sequence sets corresponding to each set of correction coefficient sequence sets.
[0054] For each set of correction coefficient-temperature mapping points, first calculate the mean of the ordinate of the correction coefficients of all mapping points in the set. Then, construct a two-dimensional coordinate system with temperature as the abscissa and correction coefficient as the ordinate. Draw multiple straight lines that pass through the origin of the coordinate axis and whose slopes correspond to the mean of the ordinates. Use these straight lines as the initial consistency screening lines for the corresponding set of mapping points.
[0055] Based on multiple initial consistency screening lines, iterative consistency screening is carried out on each set of correction coefficient-temperature mapping points. By judging whether the distance from each mapping point to the screening line meets the preset threshold, the position of the line is gradually optimized and valid mapping points that meet the consistency requirements are retained, while outliers with large dispersion are eliminated. Finally, the optimal line determined after iterative optimization is used as the target mapping relationship of the set of sequences, forming multiple target correction coefficient-temperature mapping relationship models that can stably reflect the law of change of correction coefficient with temperature.
[0056] In one possible implementation, step S332 further includes:
[0057] Count the number of upper mapping points located above the multiple initial consistency screening lines and the number of lower mapping points located below the multiple initial consistency screening lines.
[0058] When the number of the plurality of upper mapping points is greater than or equal to the number of the plurality of lower mapping points, the direction of upward movement will be used as the consistency filtering direction.
[0059] When the number of the plurality of upper mapping points is less than the number of the plurality of lower mapping points, the downward movement will be used as the consistency filtering direction.
[0060] The multiple initial consistency screening lines are moved according to the consistency screening direction to obtain multiple iterative consistency screening lines.
[0061] Determine whether the multiple iterative consistency screening lines can replace the multiple initial consistency screening lines. If so, continue iterating the multiple iterative consistency screening lines according to the consistency screening direction.
[0062] If not, then the multiple initial consistency screening lines will be used as multiple target correction coefficient-temperature mapping relationship models.
[0063] Specifically, for each set of correction coefficient-temperature mapping point sequences and its corresponding initial consistency screening line, the position distribution of each mapping point relative to the line is determined one by one, and the number of all upper mapping points above the initial consistency screening line and the number of all lower mapping points below the initial consistency screening line are counted and recorded.
[0064] The number of upper mapping points and the number of lower mapping points are compared. If the number of upper mapping points above the initial consistency screening line in a certain correction coefficient-temperature mapping point sequence set is greater than or equal to the number of lower mapping points below the line, then the upward movement is set as the consistency screening direction corresponding to the sequence set, which is used to guide the translation adjustment of the consistency screening line in subsequent iterations.
[0065] When the number of mapping points above the initial consistency screening line obtained from statistics is less than the number of mapping points below it, it is determined that the group of correction coefficient-temperature mapping points is biased downwards on the line. Based on this, the downward movement is determined as the iteration direction of this consistency screening.
[0066] Based on the previously determined consistency screening direction, each initial consistency screening line is shifted and adjusted in the corresponding direction: the line is moved slightly upward in the upward direction and slightly downward in the downward direction. After the shift is completed, multiple updated iterative consistency screening lines are obtained, which serve as the basis for the next iteration judgment.
[0067] Compare the distances from each mapping point sequence set to the iterative consistency screening line and the initial consistency screening line to see if they meet the preset threshold, and count the number of valid mapping points that meet the condition. If the number of valid mapping points corresponding to the iterative line is greater, it is determined that the iterative consistency screening line can replace the initial consistency screening line, and a new round of translation iteration is carried out on the current iterative line along the determined consistency screening direction to further optimize the consistency of the mapping relationship.
[0068] If it is determined that the iterative consistency screening line cannot replace the initial consistency screening line, that is, the number of valid mapping points that meet the preset distance threshold has not been increased after iteration, then the iterative optimization is stopped, and the current initial consistency screening line is directly used as the target line corresponding to the group, thereby forming the final target correction coefficient-temperature mapping relationship model.
[0069] In one possible implementation, step S332 further includes:
[0070] The number of mapping points in the set of multiple correction coefficient-temperature mapping points whose distances to the multiple iterative consistency screening lines and the multiple initial consistency screening lines satisfy a preset distance threshold is counted, thus obtaining the number of multiple iterative mapping points and the number of multiple initial mapping points.
[0071] If the number of multiple iterative mapping points is greater than or equal to the number of multiple initial mapping points, then multiple iterative consistency screening lines can replace multiple initial consistency screening lines.
[0072] Specifically, for each set of correction coefficient-temperature mapping point sequences, the number of valid mapping points whose distance to the iterative consistency screening line is less than or equal to a preset distance threshold is counted to obtain the number of iterative mapping points; at the same time, the number of valid mapping points whose distance to the initial consistency screening line satisfies the same preset distance threshold is counted to obtain the number of initial mapping points.
[0073] If, under the same set of correction coefficient-temperature mapping point sequences, the number of iterative mapping points that meet the threshold condition is greater than or equal to the number of initial mapping points, it indicates that the iterative consistency screening line has a better fit to the effective mapping points, and it can be determined that the iterative consistency screening line can replace the original initial consistency screening line.
[0074] In one possible implementation, step S332 further includes:
[0075] If the number of multiple iterative mapping points is less than the number of multiple initial mapping points, then multiple iterative consistency screening lines cannot replace multiple initial consistency screening lines.
[0076] Specifically, if the number of iterative mapping points that satisfy the preset distance threshold in the same set of correction coefficient-temperature mapping point sequences is less than the number of initial mapping points, it indicates that the fitting effect of the iterative consistency screening line is not as good as that of the initial consistency screening line. Therefore, it is determined that the iterative consistency screening line cannot replace the initial consistency screening line.
[0077] Example 2, based on the same inventive concept as the core nuclear magnetic resonance measurement correction method in the aforementioned examples, such as... Figure 2 As shown, this application provides a core nuclear magnetic resonance measurement correction system for high-altitude environments. The system and method embodiments in this application are based on the same inventive concept. The system includes:
[0078] The reference NMR parameter acquisition module 10 is used to acquire multiple core sample sets from multiple work areas, perform sample preprocessing, conduct reference NMR measurements at standard laboratory temperatures, and acquire multiple reference NMR parameters.
[0079] The experimental NMR parameter sequence set acquisition module 20 is used to place multiple pre-processed core sample sets in a temperature-controlled environment, conduct NMR experiments under variable temperature conditions according to a preset temperature sequence, collect NMR data at each temperature point, and obtain multiple experimental NMR parameter sequence sets.
[0080] The calibration model construction module 30 is used to perform nuclear magnetic resonance calibration analysis based on the multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, and to construct multiple total porosity calibration models and multiple T2 spectral morphology calibration models.
[0081] The real-time NMR parameter acquisition module 40 is used to simultaneously acquire real-time ambient temperature and real-time core sample type characteristics when performing core NMR measurements in the field. Based on the real-time core sample type characteristics, it matches multiple total porosity correction models and multiple T2 spectral morphology correction models to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. It then performs real-time correction of the measurement results to obtain the real-time NMR parameters.
[0082] Furthermore, the system is also used to implement the following functions:
[0083] Each of the multiple reference NMR parameters includes a reference T2 spectrum and a reference total porosity.
[0084] Furthermore, the system is also used to implement the following functions:
[0085] The core samples were placed in a temperature-controlled environment chamber and subjected to cooling-constant-measurement-heating at different temperature points according to a preset temperature sequence. Nuclear magnetic resonance measurements were performed at each temperature point, and the experimental T2 spectrum and experimental baseline total porosity were recorded to obtain a set of multiple experimental nuclear magnetic parameter sequences.
[0086] Furthermore, the system is also used to implement the following functions:
[0087] Based on multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, a total porosity change rate analysis was performed to obtain multiple sets of total porosity change rate sequences. A correction analysis was then performed using these multiple sets of total porosity change rate sequences to construct multiple total porosity correction models. Finally, based on multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, a T2 spectral morphology shift characteristic analysis was performed to construct multiple T2 spectral morphology correction models.
[0088] Furthermore, the system is also used to implement the following functions:
[0089] Correction coefficient analysis is performed on the multiple sets of total porosity change rate sequences to obtain multiple sets of correction coefficient sequences; consistency screening of the multiple sets of correction coefficient sequences is performed to obtain multiple target correction coefficient-temperature mapping relationship models; based on the multiple target correction coefficient-temperature mapping relationship models, the multiple total porosity correction models are constructed.
[0090] Furthermore, the system is also used to implement the following functions:
[0091] Using temperature as the horizontal axis and correction coefficient as the vertical axis, multiple sets of correction coefficient-temperature mapping point sequences are constructed based on the multiple sets of correction coefficient sequences. Multiple straight lines passing through the origin of the coordinate axis and corresponding to the mean of the vertical coordinates of the mapping points in the multiple sets of correction coefficient-temperature mapping point sequences are used as multiple initial consistency screening lines. Based on the multiple initial consistency screening lines, the multiple sets of correction coefficient-temperature mapping point sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping relationship models.
[0092] Furthermore, the system is also used to implement the following functions:
[0093] The number of upper mapping points above the initial consistency screening lines and the number of lower mapping points below the initial consistency screening lines are counted. When the number of upper mapping points is greater than or equal to the number of lower mapping points, the line is moved upward as the consistency screening direction. When the number of upper mapping points is less than the number of lower mapping points, the line is moved downward as the consistency screening direction. The initial consistency screening lines are moved according to the consistency screening direction to obtain multiple iterative consistency screening lines. It is determined whether the multiple iterative consistency screening lines can replace the initial consistency screening lines. If so, the multiple iterative consistency screening lines are iterated according to the consistency screening direction. If not, the multiple initial consistency screening lines are used as multiple target correction coefficient-temperature mapping relationship models.
[0094] Furthermore, the system is also used to implement the following functions:
[0095] The number of mapping points in the set of multiple correction coefficient-temperature mapping points whose distances to the multiple iterative consistency screening lines and the multiple initial consistency screening lines satisfy a preset distance threshold is counted to obtain the number of multiple iterative mapping points and the number of multiple initial mapping points; if the number of multiple iterative mapping points is greater than or equal to the number of multiple initial mapping points, then the multiple iterative consistency screening lines can replace the multiple initial consistency screening lines.
[0096] Furthermore, the system is also used to implement the following functions:
[0097] If the number of multiple iterative mapping points is less than the number of multiple initial mapping points, then multiple iterative consistency screening lines cannot replace multiple initial consistency screening lines.
[0098] It should be noted that the order of the embodiments described above is for descriptive purposes only and does not represent the superiority or inferiority of the embodiments. Specific embodiments of this specification have been described above. Furthermore, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.
[0099] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
[0100] This specification and accompanying drawings are merely illustrative examples of this application and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Therefore, if such modifications and variations fall within the scope of this application and its equivalents, this application intends to include such modifications and variations.
Claims
1. A method for correcting core nuclear magnetic resonance measurements in high-altitude environments, characterized in that, The method includes: Multiple core sample sets from multiple work areas were obtained, sample pretreatment was performed, and reference nuclear magnetic resonance measurements were conducted at standard laboratory temperature to obtain multiple reference nuclear magnetic parameters. Multiple pretreated core samples were placed in a temperature-controlled environment and nuclear magnetic resonance experiments were conducted under variable temperature conditions according to a preset temperature sequence. Nuclear magnetic resonance data were collected at each temperature point to obtain multiple sets of experimental nuclear magnetic parameter sequences. Based on the multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, NMR correction analysis was performed to construct multiple total porosity correction models and multiple T2 spectral morphology correction models. When performing core NMR measurements in the field, real-time ambient temperature and real-time core sample type characteristics are acquired simultaneously. Based on the real-time core sample type characteristics, multiple total porosity correction models and multiple T2 spectral morphology correction models are matched to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. The measurement results are then corrected in real time to obtain the corrected real-time NMR parameters.
2. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 1, characterized in that, Each of the multiple reference NMR parameters includes a reference T2 spectrum and a reference total porosity.
3. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 1, characterized in that, Multiple pretreated core samples were placed in a temperature-controlled environment, and nuclear magnetic resonance (NMR) experiments were conducted under varying temperatures according to a preset temperature sequence. NMR data were collected at each temperature point, resulting in multiple sets of experimental NMR parameter sequences, including: The multiple core samples were placed in a temperature-controlled environmental chamber and subjected to cooling-constant temperature-measurement-heating at different temperature points according to a preset temperature sequence. Nuclear magnetic resonance measurements were performed at each temperature point to record the experimental T2 spectrum and the experimental baseline total porosity, resulting in a set of multiple experimental NMR parameter sequences.
4. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 1, characterized in that, Based on the aforementioned sets of experimental NMR parameter sequences and multiple reference NMR parameters, NMR correction analysis was performed to construct multiple total porosity correction models and multiple T2 spectral morphology correction models, including: Based on multiple sets of experimental NMR parameter sequences and multiple benchmark NMR parameters, a mapping analysis of the total porosity change rate was performed to obtain multiple sets of total porosity change rate sequences. By combining the multiple sets of total porosity change rate sequences, correction analysis is performed to construct multiple total porosity correction models; Based on multiple sets of experimental NMR parameter sequences and multiple benchmark NMR parameters, the morphological shift characteristics of mapped T2 spectra are analyzed, and multiple T2 spectra morphological correction models are constructed.
5. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 4, characterized in that, By combining the aforementioned sets of total porosity change rate sequences for correction analysis, multiple total porosity correction models are constructed, including: Correction coefficient analysis was performed on the multiple sets of total porosity change rate sequences to obtain multiple sets of correction coefficient sequences; The multiple sets of correction coefficient sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping relationship models; Based on the multiple target correction coefficient-temperature mapping relationship models, the multiple total porosity correction models are constructed.
6. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 5, characterized in that, The multiple sets of correction coefficient sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping models, including: With temperature as the horizontal axis and correction coefficient as the vertical axis, construct multiple sets of correction coefficient-temperature mapping point sequences based on the multiple sets of correction coefficient sequences; Multiple straight lines that pass through the origin of the coordinate axis and are related to the mean of the ordinate of the mapping points in the set of multiple correction coefficient-temperature mapping points are used as multiple initial consistency screening lines. Based on the multiple initial consistency screening lines, the multiple sets of correction coefficient-temperature mapping point sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping relationship models.
7. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 6, characterized in that, Based on the multiple initial consistency screening lines, the multiple sets of correction coefficient-temperature mapping point sequences are subjected to consistency screening to obtain multiple target correction coefficient-temperature mapping relationship models, including: Count the number of upper mapping points located above the multiple initial consistency screening lines and the number of lower mapping points located below the multiple initial consistency screening lines; When the number of the plurality of upper mapping points is greater than or equal to the number of the plurality of lower mapping points, the direction of upward movement will be used as the consistency filtering direction. When the number of the plurality of upper mapping points is less than the number of the plurality of lower mapping points, the downward movement will be used as the consistency filtering direction. The multiple initial consistency screening lines are moved according to the consistency screening direction to obtain multiple iterative consistency screening lines; Determine whether the multiple iterative consistency screening lines can replace the multiple initial consistency screening lines. If so, continue iterating the multiple iterative consistency screening lines according to the consistency screening direction. If not, then the multiple initial consistency screening lines will be used as multiple target correction coefficient-temperature mapping relationship models.
8. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 7, characterized in that, Determining whether the multiple iterative consistency screening lines can replace multiple initial consistency screening lines includes: The number of mapping points in the multiple correction coefficient-temperature mapping point sequence set whose distances to the multiple iterative consistency screening lines and the multiple initial consistency screening lines satisfy a preset distance threshold is counted to obtain the number of multiple iterative mapping points and the number of multiple initial mapping points. If the number of multiple iterative mapping points is greater than or equal to the number of multiple initial mapping points, then multiple iterative consistency screening lines can replace multiple initial consistency screening lines.
9. The method for core nuclear magnetic resonance measurement correction in a high-altitude environment as described in claim 8, characterized in that, If the number of multiple iterative mapping points is less than the number of multiple initial mapping points, then multiple iterative consistency screening lines cannot replace multiple initial consistency screening lines.
10. A core nuclear magnetic resonance measurement correction system for high-altitude environments, characterized in that, The system is used to implement the core nuclear magnetic resonance measurement correction method according to any one of claims 1-9, and the system includes: The reference NMR parameter acquisition module is used to acquire multiple core sample sets from multiple work areas, perform sample pretreatment, conduct reference NMR measurements at standard laboratory temperatures, and acquire multiple reference NMR parameters. The experimental NMR parameter sequence set acquisition module is used to place multiple pre-processed core sample sets in a temperature-controlled environment, conduct NMR experiments under variable temperature conditions according to a preset temperature sequence, collect NMR data at each temperature point, and obtain multiple experimental NMR parameter sequence sets. The calibration model construction module is used to perform nuclear magnetic resonance calibration analysis based on the multiple sets of experimental NMR parameter sequences and multiple reference NMR parameters, and to construct multiple total porosity calibration models and multiple T2 spectral morphology calibration models. The real-time NMR parameter acquisition module is used to simultaneously acquire real-time ambient temperature and real-time core sample type characteristics when performing core NMR measurements in the field. Based on the real-time core sample type characteristics, multiple total porosity correction models and multiple T2 spectral morphology correction models are matched to obtain a matched total porosity correction model and a matched T2 spectral morphology correction model. The measurement results are then corrected in real time to obtain the real-time NMR parameters.