A well seismic calibration method, device and related equipment

Abstract

The present invention discloses a well seismic calibration method, apparatus, and related equipment. The method may include: generating a synthetic seismic record for a single well based on acoustic wave time difference and density curves obtained from well logging; performing well seismic calibration based on the synthetic seismic record and seismic profiles from near-well seismic data to determine the time-depth relationship of the well; based on the time-depth relationship of the single-well well seismic calibration, performing a comparative analysis of the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in a study area to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies; based on the statistical relationship between the average velocity and burial depth of the strata in different sedimentary facies, performing a well-linked seismic profile analysis on the well seismic calibration results of all wells in the study area to determine the time-depth relationship of the well seismic calibration in the study area. This method improves the accuracy of the time-depth relationship of a single well and the accuracy of the time-depth relationship of multiple wells in different sedimentary facies.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, in particular to seismic geological data processing, and in particular to a well seismic calibration method, device and related equipment. Background Art

[0002] In integrated seismic-geological research, the accuracy of the time-depth relationship determined by well-seismic calibration has a significant impact on seismic interpretation, structural research, and subsequent prediction of reservoir spatial distribution, analysis of reservoir fluid spatial variation, development plan design, and well placement adjustments. Currently, the main approaches for constructing the time-depth relationship between geological data such as depth-domain well logging and time-domain seismic data include velocity functions established during seismic data processing, VSP well logging data, and well-seismic calibration of synthetic seismic records. Well-seismic calibration using synthetic seismic records is the most commonly used method in current research. In order to improve the accuracy and rationality of time-depth calibration, some researchers applied the three-dimensional velocity field obtained by block polynomial surface fitting to seismic layer calibration, providing a more accurate time-depth relationship for areas lacking VSP logging data; Luo Yin et al. used the zero-bias VSP offset correction method to study how to improve the accuracy of the time-depth relationship; Xiao Yi et al. judged the reliability of the time-depth relationship by correcting the environmental factors of the acoustic time difference and density logging curves used to produce synthetic seismic records; Bian Lien et al. used the time-depth mapping method to analyze the time-depth relationship of inclined strata; Yang Haichang et al. discussed the influence of seismic profile polarity on layer calibration based on the analysis of the relationship between seismic wavelets, polarity and time-depth. Summary of the Invention

[0003] The inventors found that the above studies used different types of data and explored the establishment of accurate and reasonable time-depth relationships based on different starting points, but there are still certain deficiencies, mainly manifested in: (1) The influence of different sedimentary facies belts on the time-depth relationship is not fully considered; a certain exploration target layer segment may usually contain strata from multiple sedimentary periods, and their sedimentary facies types may be different. Different sedimentary facies belts have different sedimentary environments and sediment characteristics, and may also have different formation velocities, which may lead to different time-depth relationships. (2) The changes in the time-depth relationship between drilling wells are not fully considered. That is, if only the time-depth relationship of a single well or a few wells is used to guide the well-seismic calibration of the entire study area, large errors or multiple solutions may occur. (3) The correlation coefficient between the synthetic seismic records produced by comparing the acoustic time difference and density logging curve and the seismic traces near the well is used as the basis for the accuracy of well-seismic calibration, which has great uncertainty.

[0004] In view of the above problems, the present invention is proposed to provide a well seismic calibration method, apparatus and related equipment that overcome the above problems or at least partially solve the above problems.

[0005] In a first aspect, an embodiment of the present invention provides a well seismic calibration method, which may include:

[0006] Generate synthetic seismic records of a single well based on the acoustic time difference and density curves obtained from well logging;

[0007] Performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellbore seismic data to determine the time-depth relationship of the drilling well;

[0008] Based on the time-depth relationship of the well-seismic calibration, a comparative analysis of the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area was conducted to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies;

[0009] Based on the statistical relationship between the average velocity of the strata in different sedimentary phases and the burial depth of the strata, a well-linked seismic profile analysis was performed on all the wells in the study area to determine the time-depth relationship of the well-seismic calibration in the study area.

[0010] Optionally, after performing well-seismic calibration based on the synthetic seismic records and the seismic profiles in the wellside seismic data to determine the time-depth relationship of the drilling, the method may further include:

[0011] The time-depth relationship of the single-well seismic calibration is corrected based on the time-depth relationship data obtained from VSP logging.

[0012] Optionally, the relationship between the average velocity and burial depth of the formation in different sedimentary facies zones based on statistics, before performing well-linked seismic profile analysis on all wells in the study area, further includes:

[0013] Fitting the time-depth relationship of single well calibration in different sedimentary facies belts in the study area to determine the correlation coefficient of the fitted curves of different sedimentary facies belts;

[0014] The correlation coefficient is compared with the correlation coefficient of the time-depth relationship fitting curve of all single wells in the study area to verify the differences in the time-depth relationship calibrated in different sedimentary facies belts.

[0015] Optionally, generating a synthetic seismic record of a single well based on the acoustic time difference and density curve obtained from well logging may include:

[0016] After converting the acoustic time difference curve into a velocity curve, the velocity curve is multiplied by the density curve to obtain the longitudinal wave impedance data of the well;

[0017] determining a reflection coefficient of the wellbore based on the longitudinal wave impedance data;

[0018] A convolution process is performed on the reflection coefficient and wavelet data in the seismic data to generate a synthetic seismic record of a single well.

[0019] Optionally, performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellside seismic data to determine the time-depth relationship of the drilling may include:

[0020] performing a correlation analysis based on the synthetic seismic record of the single well and the seismic profile data to determine a correlation coefficient;

[0021] According to the comparison result of the correlation coefficient and a preset correlation coefficient threshold, the wellbore is calibrated by seismic calibration to determine the time-depth relationship of the wellbore.

[0022] Optionally, performing a well-linked seismic profile analysis on all wells in the study area to determine the time-depth relationship of well-seismic calibration in the study area may include:

[0023] The time-depth relationship of the well-seismic calibration of all the wells in the study area is projected onto the seismic profile to perform well-linked seismic profile analysis, determine the isochronous interface of the phase axis of the sedimentary strata in the study area, and determine the time-depth relationship of the well-seismic calibration in the study area.

[0024] Optionally, the method may further include:

[0025] Screening all the wells in the study area according to preset conditions to determine the backbone wells in the study area;

[0026] The preset conditions include: the completeness of the target layer section encountered and / or the completeness of the logging curve.

[0027] In a second aspect, an embodiment of the present invention provides a well seismic calibration device, which may include:

[0028] A generation module for generating synthetic seismic records of a single well based on the acoustic time difference and density curves obtained from well logging;

[0029] a calibration module for performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellside seismic data to determine the time-depth relationship of the drilling;

[0030] A comparison module, based on the time-depth relationship of the well-seismic calibration, compares and analyzes the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area, so as to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies;

[0031] The determination module is used to perform a well-linked seismic profile analysis on all wells in the study area based on the statistical relationship between the average velocity of the formation in different sedimentary phase zones and the burial depth of the formation, so as to determine the time-depth relationship of the well-seismic calibration in the study area.

[0032] In a third aspect, an embodiment of the present invention provides an application of the well-seismic calibration time-depth relationship of a study area obtained by the well-seismic calibration method described in the first aspect.

[0033] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the well seismic calibration method as described in the first aspect.

[0034] In a fourth aspect, an embodiment of the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the well seismic calibration method as described in the first aspect is implemented.

[0035] The beneficial effects of the above technical solutions provided by the embodiments of the present invention include at least:

[0036] The present invention provides a well seismic calibration method, apparatus, and related equipment. The method may include: generating a synthetic seismic record for a single well based on acoustic wave time difference and density curves obtained from well logging; performing well seismic calibration based on the synthetic seismic record and seismic profiles in wellside seismic data to determine the time-depth relationship of the well; based on the time-depth relationship of the well seismic calibration, performing a comparative analysis of the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in a study area to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies; and performing a well-linked seismic profile analysis of all wells in the study area based on the statistical relationship between the average velocity and burial depth of the strata in different sedimentary facies to determine the time-depth relationship of the well seismic calibration in the study area. This method simultaneously controls and verifies the accuracy and rationality of well seismic calibration results in different sedimentary facies from both seismic and geological perspectives, improving the accuracy of the time-depth relationship of a single well and the time-depth relationship of multiple wells in different sedimentary facies. Furthermore, the analysis method can also be applied to stratigraphic correlation work after extension.

[0037] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0040] Figure 1 A schematic flow chart of a well seismic calibration method provided in an embodiment of the present invention;

[0041] Figure 2 A schematic flow chart of a specific well seismic calibration method provided in an embodiment of the present invention;

[0042] Figure 3 Schematic diagram of the process of step S23;

[0043] Figure 4 This is an effect diagram of measuring the calibration result based on the correlation coefficient provided in an embodiment of the present invention;

[0044] Figure 5 is a flow chart of step S24;

[0045] Figure 6 A schematic diagram of correcting the time-depth relationship of a single well based on VSP logging provided in an embodiment of the present invention;

[0046] Figure 7 A flow chart for verifying the time-depth relationship of different sedimentary facies belts provided in an embodiment of the present invention;

[0047] Figure 8 This is a schematic diagram of the time-depth relationship of well-seismic calibration in a certain study area provided in an embodiment of the present invention;

[0048] Figure 9 This is an effect diagram of the time-depth relationship of the well-linked seismic profile in an embodiment of the present invention;

[0049] Figure 10 This is a rendering of the effect of stratum sedimentation on seismic events provided in an embodiment of the present invention;

[0050] Figure 11 Schematic diagram of the structure of the well seismic calibration device provided in an embodiment of the present invention. DETAILED DESCRIPTION

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

[0052] In an embodiment of the present invention, a well seismic calibration method is provided, which is used to perform well seismic calibration on seismic data in a study area, a work area, or a certain oil field area, wherein the purpose of the well seismic calibration is to establish a time-depth relationship between depth-domain geological data and time-domain seismic data, so as to serve as a basis for subsequent seismic interpretation, stratigraphic interpretation, stratigraphic comparison, inversion, or rock formation attribute analysis. To this end, an embodiment of the present invention intends to establish a set of methods for testing the reliability and rationality of time-depth relationship calibration for stable sedimentary strata by analyzing the factors that affect the accuracy of well seismic time-depth relationship calibration, in order to improve the accuracy of well seismic calibration and provide support for subsequent related research and production.

[0053] Reference Figure 1 , the method may include the following steps:

[0054] Step S11: Generate a synthetic seismic record of a single well based on the acoustic wave time difference and density curve obtained by well logging.

[0055] This step is to generate synthetic seismic records of all wells in the study area based on the acoustic wave time difference and density curve obtained from each well logging data, and then generate synthetic seismic records of all wells in the study area.

[0056] Step S12: Based on the synthetic seismic records and the seismic profiles in the wellbore seismic data, wellbore seismic calibration is performed to determine the time-depth relationship of the drilling.

[0057] This step is to match the wave group relationship between the synthetic seismic record and the seismic profile in the wellside seismic data of the single well, thereby completing the well seismic calibration and determining the time-depth relationship of the well.

[0058] Step S13: Based on the time-depth relationship of well-seismic calibration, a comparative analysis is performed on the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies.

[0059] This step is to compare and analyze the burial depth and average velocity of all sequence interfaces in wells distributed in different sedimentary facies in the study area based on the results of single-well seismic calibration. The relationship (exponential relationship) between the average velocity and burial depth of the formation in different sedimentary facies is statistically analyzed to clarify the control effect of sedimentary facies on the change of average formation velocity.

[0060] It should be noted that there may be multiple sequence interfaces in the study area. When performing comparative analysis, one sequence interface may be used for comparative analysis, or multiple sequence interfaces may be used for comparative analysis together. This embodiment of the present invention does not specifically limit this.

[0061] Step S14: Based on the statistical relationship between the average velocity of the strata in different sedimentary facies and the burial depth of the strata, a well-linked seismic profile analysis is performed on all the wells in the study area to determine the time-depth relationship of the well-seismic calibration in the study area.

[0062] In this step, the rationality and accuracy of the well-seismic time-depth relationship calibration results are checked and comprehensively analyzed through time-depth relationship analysis of sedimentary facies zones and well-linked comparative analysis methods, and the time-depth relationship of the well-seismic calibration in the study area is determined.

[0063] The inventors of this application have innovatively proposed that, when establishing the time-depth relationship between seismic and well logging, the accuracy of well-seismic calibration can be checked based on the understanding that the velocities of layers within the same sedimentary facies exhibit a uniform pattern of change. This allows for precise determination of the time-depth relationship in the study area, providing reliable basic data for subsequent comprehensive geological applications. Furthermore, this method simultaneously quality controls and verifies the accuracy and rationality of well-seismic calibration results across different sedimentary facies from both a seismic and geological perspective, improving the accuracy of both single-well and multi-well time-depth relationships across different sedimentary facies. Furthermore, this analytical method can also be extended to stratigraphic correlation.

[0064] In a specific embodiment, referring to Figure 2 As shown, the above-mentioned well seismic calibration method may include the following steps:

[0065] Step S21: Acquire depth-domain geological data and time-domain seismic data within the study area.

[0066] Among them, depth domain geological data may include: sedimentary phase plane distribution data, geological stratification data, and logging data (acoustic time difference data, density curve data); time domain seismic data may include: post-stack seismic data, velocity data volume, seismic layer data, seismic wavelet, VSP time-depth data, etc.

[0067] Step S22: Screen all the wells in the study area according to preset conditions to determine the backbone wells in the study area;

[0068] The preset conditions may include: the completeness of the target layer section encountered and / or the completeness of the logging curve.

[0069] Drilling encounters refer to drilling through a set of strata and encountering a specific stratum at a certain depth. This typically refers to the target stratum, oil and gas reservoir, or specific rock formations. In this step, all wells in the study area are screened and selected as backbone wells that have fully encountered the target stratum and have good logging curves. Seismic calibration is performed on these backbone wells to determine the time-depth relationship within the study area.

[0070] Step S23: Generate a synthetic seismic record of a single well based on the acoustic wave time difference and density curve obtained from the well logging. This step can refer to step S11 in the above embodiment and will not be described in detail here.

[0071] In an alternative embodiment, referring to Figure 3 As shown, step S23 may specifically include the following steps:

[0072] Step S231: After converting the acoustic wave time difference curve into a velocity curve, multiply it with the density curve to obtain the longitudinal wave impedance data of the drilling.

[0073] Step S232: Determine the reflection coefficient of the well based on the longitudinal wave impedance data.

[0074] Step S233: Perform convolution processing on the wavelet data in the seismic data based on the reflection coefficient to generate a synthetic seismic record of a single well.

[0075] Reference Figure 4 As shown, Figure 4 The gray earthquake data near 1015 are earthquake records synthesized by the above method.

[0076] Step S24: Based on the synthetic seismic records and the seismic profiles in the wellside seismic data, well-seismic calibration is performed to determine the time-depth relationship of the drilling. This step can refer to the above-mentioned step S12 and will not be repeated here. It should be noted that in the embodiment of the present invention, calibration is performed for formations with relatively stable sedimentary characteristics and relatively stable formation velocities, and a relatively stable score in the seismic data and well logging curves. Such formations (such as clastic sedimentary formations) are relatively stable in the entire study area. However, the velocity of igneous rock formations is relatively high, and there are sudden changes in velocity in the seismic data, which usually reduces the accuracy of well-seismic calibration.

[0077] Reference Figure 4 As shown, the black background seismic data represents the seismic profile from the wellbore seismic data. In this embodiment of the present invention, the inventors matched synthetic seismic records generated from depth-domain geological data with actual seismic profiles in the time domain to determine the time-depth relationship. Specifically, when establishing the time-depth relationship, the geological horizon corresponds to which wave group, or location within a wave group, on the seismic profile.

[0078] In an alternative embodiment, referring to Figure 5 As shown, step S24 may specifically include the following steps:

[0079] Step S241: performing correlation analysis on the synthetic seismic record of a single well and the seismic profile data to determine a correlation coefficient.

[0080] Step S242: Based on the comparison result of the correlation coefficient and the preset correlation coefficient threshold, the wellbore seismic calibration is performed on the well to determine the time-depth relationship of the drilling.

[0081] The inventors have found that in actual production, if the accuracy of the well-seismic time-depth relationship calibration is judged only based on the correlation coefficient between the synthetic seismic record and the wellside seismic trace, there will inevitably be a large number of solutions.

[0082] Step S25: Correct the time-depth relationship of the single well seismic calibration based on the time-depth relationship data obtained by VSP logging.

[0083] Reference Figure 6 As shown, based on the use of VSP logging data to verify the accuracy of the time-depth relationship of well-seismic calibration, the inventors corrected the multi-solution nature of the well-seismic calibration process in step S24 above and adjusted the time-depth relationship of the synthetic record to ensure that the wave group relationship of the synthetic seismic record strictly matches the wave group relationship of the wellside track seismic record, completing the well-seismic calibration and determining the time-depth relationship of the single well. In this embodiment, VSP logging data can provide accurate velocity parameters, time-depth relationship parameters, and other parameters. The time-depth relationship determined through well-seismic calibration should be consistent with the time-depth relationship provided by VSP logging. Therefore, using data from a well with VSP logging in the study area can guide and control the well-seismic calibration work of other wells in the study area that are not too far from VSP wells.

[0084] Step S26: Based on the time-depth relationship of well-seismic calibration, a comparative analysis is performed on the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies.

[0085] In this embodiment of the present invention, after quality control of the VSP data and completion of well-seismic calibration, the well-seismic calibration results were used to compare the burial depth and average velocity of at least one sequence boundary in wells distributed across different sedimentary facies zones within the study area. This revealed that, when the burial depths of the formations were the same or similar, the average velocity of the fan delta facies zone was significantly lower than that of the nearshore underwater fan facies zone. The relationships between the average velocity and burial depth of the fan delta facies zone and the nearshore underwater fan facies zone were statistically analyzed, showing an exponential relationship. This indicates that the average velocity of a stratigraphic layer within the same sedimentary facies zone and the same depositional period exhibits a uniform variation pattern. Furthermore, despite the same depositional period, different sedimentary facies zones exhibit different relationships between average velocity and burial depth due to differences in lithology and other aspects of the formations, indicating that the sedimentary facies zone exerts a controlling influence on the variation in average velocity. After quality control of the VSP data and completion of well-seismic calibration, a comparison of the top burial depth and average velocity of the target layer in wells distributed across different sedimentary facies within the study area was conducted based on the calibration results. The results show that, for formations with the same or similar burial depths, the average velocity in the fan delta facies is significantly lower than that in the nearshore underwater fan facies. The relationships between the average velocity and burial depth for both the fan delta facies and the nearshore underwater fan facies are exponential, indicating that the average velocity of a stratigraphic layer within the same sedimentary facies during the same depositional period exhibits a uniform variation pattern. Furthermore, despite the same depositional period, different sedimentary facies belts exhibit different relationships between average velocity and burial depth due to differences in lithology and other aspects of the formation, indicating that the sedimentary facies controls the variation in average velocity.

[0086] In an optional embodiment, the verification of the actual relationship of the same sequence interface calibration in different sedimentary facies belts is carried out by referring to Figure 7 As shown, the following steps may be included:

[0087] Step S71 : fitting the time-depth relationship based on the calibration of the single wells in different sedimentary facies belts in the study area to determine the correlation coefficients of the fitted curves of the different sedimentary facies belts.

[0088] Of course, before this step, it is also necessary to fit the time-depth relationship of all single well calibrations in the study area to determine the correlation coefficient of the fitting curve of the time-depth relationship of all single well calibrations in the study area.

[0089] Specifically, a scatter plot is generated by plotting the two-way travel time (TWT) for each seismic reflection layer in each well against the corresponding geological depth. The horizontal axis represents the TWT (in milliseconds), with values ​​increasing to the right, and the vertical axis represents the measured depth (in meters), with depth increasing downward. The scatter plot shows that layers with the same burial depth and the same sedimentary facies should have similar or similar interval velocities; that layers with the same lithology during the same depositional period generally have similar or similar interval velocities; and that interval velocities within the same sedimentary facies tend to increase regularly with increasing burial depth. The various coefficients in the exponential relationship vary, indicating that different sedimentary facies have different time-depth relationships, or that a single sedimentary facies corresponds to a specific velocity relationship.

[0090] In a specific example, a certain study area selected in the embodiment of the present invention can be divided into a gentle slope zone and a steep slope zone according to structural characteristics. The target layer, the second section of the Tengger Formation of the Lower Cretaceous, mainly develops fan delta in the gentle slope zone and nearshore underwater fan deposits in the steep slope zone. The fan delta phase mainly develops light gray sandstone, sandstone and conglomerate, gray-green mud siltstone and gray-green and dark gray mudstone interbedded with unequal thickness; the nearshore underwater fan phase mainly develops dark gray and gray-black volcanic breccia, tuff and purple-red, dark gray, gray-black basalt, basaltic andesite, andesite, etc., which are mainly chaotic deposits. The lithology varies greatly in the vertical and horizontal directions, and the heterogeneity is serious, but the planar distribution range is limited. The drilling results show that there are a total of 63 exploration wells that have penetrated the target layer, including 50 wells in the fan delta phase and 13 wells in the nearshore underwater fan phase. The time-depth relationship diagram after well-seismic calibration of the T3 seismic reflection layer corresponding to the top surface of the second section of the Tengger Formation of 63 exploration wells ( Figure 8 (a)) It can be seen that the correlation coefficient is 0.882. For these two sedimentary facies, the time-depth relationship of 50 wells in the fan delta facies and 13 wells in the nearshore underwater fan facies was statistically analyzed and found ( Figure 8 (b, c)), the correlation coefficients are 0.959 and 0.887, respectively, indicating that the regularity of the average velocity change in the fan delta sedimentary facies is better than that in the nearshore submarine fan sedimentary facies. Although they are both Member II of the Tengger Formation, the time-depth relationships of the fan delta facies and the nearshore submarine fan facies are statistically analyzed separately, and the various coefficients in their exponential relationships are different, indicating that the time-depth relationships of different sedimentary facies belts are different, or that a single sedimentary facies belt corresponds to a certain velocity relationship.

[0091] Step S72: Compare the correlation coefficients of the fitting curves fitted to different sedimentary facies belts with the correlation coefficients of the fitting curves fitted to the time-depth relationships calibrated by all single wells in the study area to verify the differences in the time-depth relationships calibrated by different sedimentary facies belts.

[0092] Analysis of the scatter plots reveals that the average velocity of a geological horizon follows a corresponding velocity variation pattern, regardless of whether it is a fan delta or a nearshore submarine fan sedimentary environment. If the calibration results for a particular well deviate from this variation pattern, it may be due to the following reasons: first, there may be errors in the geological stratification; second, there may be errors in the seismic events corresponding to the geological horizon during calibration; third, differences in sedimentary facies may cause the calibration results to deviate from the velocity variation pattern of the study area. If the time-depth data point after well-seismic calibration lies above the statistical average velocity variation curve, it means that the depth of the geological horizon determined in the geological stratification may be too low, in which case a sequence stratigraphic comparison should be conducted. Alternatively, the seismic reflection time corresponding to the geological horizon on the seismic profile may be too long, in which case it should be checked through seismic wave group relationships or well-joined seismic profile analysis. If the stratigraphic division results and the seismic reflection time corresponding to the geological horizon are both correct, it should be examined whether the cause is a difference in lithology or sedimentary facies type. If the time-depth data point after well seismic calibration is below the statistical average velocity change curve, the above method can be used for analysis in the same way, but the possible reason at this time is that the geological stratification depth is too large or the seismic reflection time corresponding to the geological layer is too small.

[0093] Step S27: Based on the statistical relationship between the average velocity of the strata in different sedimentary facies and the burial depth of the strata, a well-linked seismic profile analysis is performed on all the wells in the study area to determine the time-depth relationship of the well-seismic calibration in the study area.

[0094] Due to the continuous distribution of stratigraphic layers, the corresponding seismic reflection events are typically also continuously distributed on a plane and can be continuously tracked during seismic data interpretation. When using well-seismic calibration to establish the time-depth relationship between time-domain seismic data and depth-domain drilling and logging data, well-linked seismic profiles can be used to check and analyze the rationality of the calibration results for each well involved in the calibration. If there are errors in the time corresponding to a well's geological layer or stratum on the seismic profile at the well point, or if there are inconsistencies in the interpretation of seismic horizons between two wells (beyond the well points), these errors will inevitably be reflected on the well-linked seismic profile. Therefore, the rationality and accuracy of the well-linked seismic time-depth relationship calibration results are checked and comprehensively analyzed based on the corresponding time positions of the geological layers on the seismic profile and the rationality of the lateral variations of the seismic wave groups across the entire well-linked profile.

[0095] This step projects the time-depth relationship of the well-seismic calibration of all wells in the study area onto the seismic profile to conduct well-linked seismic profile analysis and determine the isochronous interface of the sedimentary strata in the study area to determine the time-depth relationship of the well-seismic calibration in the study area. Figure 9As shown in FIG, using the time-depth relationship calibrated above, the layer is tracked and interpreted on the seismic section to obtain the time-depth relationship of the entire study area, that is, the time-depth relationship in the well-linked seismic section. Figure 9 The short lines corresponding to each well are the time-depth relationships calibrated for the single well. Figure 10 As shown in FIG, it is the isochronous interface comparison effect diagram of different sequence interfaces and seismic phase axes, among which the discontinuity line (dashed line) is the sequence stratigraphic interface.

[0096] In a specific example, there are more than a thousand exploration wells and development wells in an oil field in western my country. When conducting stratigraphic comparison research, the following process can be considered: first, wells that have drilled a complete target layer and have good logging curve quality are used as backbone wells, and the depth-time relationship of the study area is established through well-seismic calibration; using the regional seismic layer tracking interpretation results, the time depth of a certain layer of a certain well to be compared is read on the seismic profile, and the depth (H) of a certain layer of a certain well to be compared is calculated (predicted) using the established depth-time relationship; on the stratigraphic comparison profile, near the calculated depth (H) of a certain layer, according to the determined stratigraphic division and comparison principles, the accurate depth of a certain layer on the stratigraphic comparison profile is analyzed, thereby realizing rapid stratigraphic comparison.

[0097] Based on the same inventive concept, a well seismic calibration device is also provided in the embodiment of the present invention. Figure 11 As shown, the device may include: a generating module 13, a calibration module 14, a comparing module 16 and a determining module 17, and its working principle is as follows:

[0098] The generation module 13 is used to generate a synthetic seismic record of a single well based on the acoustic time difference and density curve obtained by well logging;

[0099] The calibration module 14 is used to perform well-seismic calibration based on the seismic profiles in the synthetic seismic records and the wellside seismic data to determine the time-depth relationship of the drilling;

[0100] Comparison module 16 compares and analyzes the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area based on the time-depth relationship of well seismic calibration, so as to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies;

[0101] The determination module 17 is used to perform a well-linked seismic profile analysis on all wells in the study area based on the statistical relationship between the average velocity of the formation in different sedimentary phases and the burial depth of the formation, so as to determine the time-depth relationship of the well-seismic calibration in the study area.

[0102] In an alternative embodiment, referring to Figure 11As shown, a correction module 15 may also be included, and the correction module 15 is used to correct the time-depth relationship of the single well seismic calibration based on the time-depth relationship data obtained by VSP logging.

[0103] In another optional embodiment, the generation module 13 is specifically used to: convert the acoustic wave time difference curve into a velocity curve, and then multiply it with the density curve to obtain the longitudinal wave impedance data of the well; determine the reflection coefficient of the well based on the longitudinal wave impedance data; and perform convolution processing on the reflection coefficient with the wavelet data in the seismic data to generate a synthetic seismic record of a single well.

[0104] In another optional embodiment, the calibration module 14 is specifically used to: perform correlation analysis based on the synthetic seismic record of the single well and the seismic profile data to determine the correlation coefficient; and perform well seismic calibration on the well to determine the time-depth relationship of the well based on the comparison result of the correlation coefficient with a preset correlation coefficient threshold.

[0105] In another optional embodiment, the determination module 17 is specifically used to: project the time-depth relationship of the well-seismic calibration of all the wells in the study area onto the seismic profile to perform a well-linked seismic profile analysis, determine the isochronous interface of the sedimentary strata in the study area, and determine the time-depth relationship of the well-seismic calibration in the study area.

[0106] In another alternative embodiment, referring to Figure 11 As shown, a screening module 12 may also be included, and the screening module 12 is used to screen all the wells in the study area according to preset conditions to determine the backbone wells in the study area;

[0107] The preset conditions include: the completeness of the target layer section encountered and / or the completeness of the logging curve.

[0108] In another alternative embodiment, referring to Figure 11 As shown, an acquisition module 11 may also be included, and the acquisition module 11 is used to acquire depth domain geological data and time domain seismic data in the study area.

[0109] Among them, depth domain geological data may include: sedimentary phase plane distribution data, geological stratification data, and logging data (acoustic time difference data, density curve data); time domain seismic data may include: post-stack seismic data, velocity data volume, seismic layer data, seismic wavelet, VSP time-depth data, etc.

[0110] Based on the same inventive concept, embodiments of the present invention further provide an application of the well-seismic calibration time-depth relationship in a study area obtained by the well-seismic calibration method. Applications in embodiments of the present invention may include seismic interpretation, horizon interpretation, stratigraphic correlation, inversion, or rock formation attribute analysis.

[0111] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned well seismic calibration method is implemented.

[0112] Based on the same inventive concept, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the above-mentioned well seismic calibration method is implemented.

[0113] The principles of the problems solved by the above-mentioned devices, media, and related equipment in the embodiments of the present invention are similar to those of the above-mentioned methods. Therefore, their implementation can refer to the implementation of the above-mentioned methods, and the repeated parts will not be repeated.

[0114] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0115] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0116] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0117] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0118] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A well seismic calibration method, characterized in that: include: Generate synthetic seismic records of a single well based on the acoustic time difference and density curves obtained from well logging; Performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellbore seismic data to determine the time-depth relationship of the drilling well; Based on the time-depth relationship of the well-seismic calibration, a comparative analysis of the burial depth and average velocity of all sequence interfaces of all wells distributed in different sedimentary facies in the study area was conducted to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies; Verify the differences in the time-depth relationship of the same sequence interface in different sedimentary facies belts, and statistically analyze the relationship between the average velocity of each set of strata in different sedimentary facies belts and the burial depth of the strata; Based on the statistical relationship between the average velocity of the strata in different sedimentary phases and the burial depth of the strata, a well-linked seismic profile analysis was performed on all the wells in the study area to determine the time-depth relationship of the well-seismic calibration in the study area.

2. The method according to claim 1, characterized in that After performing well-seismic calibration based on the synthetic seismic records and the seismic profiles in the wellside seismic data to determine the time-depth relationship of the drilling, the method further includes: The time-depth relationship of the single-well seismic calibration is corrected based on the time-depth relationship data obtained from VSP logging.

3. The method according to claim 1, characterized in that Based on the fact that each set of strata statistically analyzed in different sedimentary facies has different average velocities and burial depths, before performing the well-linked seismic profile analysis on all the wells in the study area, the following steps are also included: Based on fitting the time-depth relationship of single well calibration in different sedimentary facies belts in the study area, the correlation coefficient of the fitted curve under the control of different sedimentary facies belts is determined; The correlation coefficient is compared with the correlation coefficient of the curve fitting of the time-depth relationship calibrated by all single wells in the study area to verify the differences in the time-depth relationship calibrated by different sedimentary facies belts.

4. The method according to claim 1, wherein The method of generating a synthetic seismic record of a single well based on the acoustic wave time difference and density curve obtained by well logging includes: After converting the acoustic time difference curve into a velocity curve, the velocity curve is multiplied by the density curve to obtain the longitudinal wave impedance data of the well; determining a reflection coefficient of the wellbore based on the longitudinal wave impedance data; A convolution process is performed on the reflection coefficient and wavelet data in the seismic data to generate a synthetic seismic record of a single well.

5. The method according to claim 4, characterized in that The method of performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellside seismic data to determine the time-depth relationship of the drilling well comprises: performing a correlation analysis based on the synthetic seismic record of the single well and the seismic profile data to determine a correlation coefficient; According to the comparison result of the correlation coefficient and a preset correlation coefficient threshold, the wellbore is calibrated by seismic calibration to determine the time-depth relationship of the wellbore.

6. The method according to claim 1, characterized in that The method of performing a well-linked seismic profile analysis on all wells in the study area to determine the time-depth relationship of the well-seismic calibration in the study area includes: The time-depth relationship of the well-seismic calibration of all the wells in the study area is projected onto the seismic profile to perform well-linked seismic profile analysis, determine the isochronous interface of the phase axis of the sedimentary strata in the study area, and determine the time-depth relationship of the well-seismic calibration in the study area.

7. The method according to any one of claims 1 to 6, characterized in that Also includes: Screening all the wells in the study area according to preset conditions to determine the backbone wells in the study area; The preset conditions include: the completeness of the target layer section encountered and / or the completeness of the logging curve.

8. A well seismic calibration device, characterized in that: include: A generation module for generating synthetic seismic records of a single well based on the acoustic time difference and density curves obtained from well logging; a calibration module for performing well-seismic calibration based on the synthetic seismic record and the seismic profile in the wellside seismic data to determine the time-depth relationship of the drilling; A comparison module, based on the time-depth relationship of the well-seismic calibration, compares and analyzes the burial depth and average velocity of all sequence interfaces of wells distributed in different sedimentary facies in the study area, so as to classify the relationship between the average velocity and burial depth of the strata in different sedimentary facies; Verification module verifies the differences in time-depth relationships of the same sequence interface in different sedimentary facies belts, so as to statistically analyze the relationship between the average velocity and burial depth of each set of strata in different sedimentary facies belts; The determination module is used to perform a well-linked seismic profile analysis on all wells in the study area based on the statistical relationship between the average velocity of the formation in different sedimentary phase zones and the burial depth of the formation, so as to determine the time-depth relationship of the well-seismic calibration in the study area.

9. An application of the well-seismic calibration time-depth relationship of a study area obtained by the well-seismic calibration method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the well seismic calibration method according to any one of claims 1 to 7 is implemented.

11. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the well seismic calibration method according to any one of claims 1 to 7 is implemented.

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