A method for seismic interface dating based on the mitchell cycle

Abstract

The application discloses a kind of based on Mitchell's cyclotron seismic interface dating method, comprising: obtaining natural gamma ray logging curve;Based on spectrum analysis, determine the energy of natural gamma ray logging curve containing Mitchell's cyclotron signal, quantity;Select the seismic interface with determined age and depth as time anchor point;From astronomical orbit model, select orbit parameter as target curve representing time domain;Based on time anchor point, determine the initial corresponding position of natural gamma ray logging curve and target curve, take it as starting point, according to the curve change of target curve, tune natural gamma ray logging curve to target curve, obtain time-depth conversion table and then determine astronomical age scale;Based on astronomical age scale, determine the age of the seismic interface to be determined.The application selects the seismic interface with absolute time as time anchor point, changes natural gamma ray logging curve from depth domain to time domain, obtains astronomical age scale, and can determine the age of seismic interface based on astronomical age scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geology analysis, in particular to a seismic interface age determination method based on Miller cycle, a computer readable storage medium and an electronic device. BACKGROUND

[0002] The seismic interface refers to the interface in the underground medium layer that can cause the reflection or refraction of artificial seismic waves, which is generally the wave impedance interface or velocity interface, and often reflects the sudden change interface of lithology. Dividing the seismic interface is one of the main tasks of petroleum seismic interpretation, and the oil storage structure unit can be judged through the seismic interface in the later period. The current seismic interface age determination is often combined with logging data and core section to determine the interface age. However, this method has problems such as inaccurate determination of horizon, inaccurate age and low precision. SUMMARY

[0003] In view of the problems in the prior art, the present application provides a seismic interface age determination method based on Miller cycle, a computer readable storage medium and an electronic device. Compared with the prior art, the present application is convenient to implement and has high analysis precision and resolution.

[0004] The present application discloses a seismic interface age determination method based on Miller cycle, comprising:

[0005] S1: obtaining a natural gamma logging curve representing the depth domain in a target area;

[0006] S2: determining the signal energy and cycle number of the natural gamma logging curve based on spectrum analysis, and judging whether the Miller cycle is contained based on the signal energy and cycle number;

[0007] S3: selecting a set of strong amplitude continuous seismic interfaces with determined age and depth in the target area as time anchor points;

[0008] S4: selecting corresponding orbit parameters from an astronomical orbit model as a target curve representing the time domain;

[0009] S5: determining the initial corresponding position of the natural gamma logging curve and the target curve based on the time anchor points, and tuning the natural gamma logging curve to the target curve according to the curve change of the target curve from the initial corresponding position as the starting point, to obtain a time-depth conversion table reflecting the corresponding relationship between the depth domain and the time domain; determining an astronomical age scale based on the continuous time-depth conversion table;

[0010] S6: determining the age of the seismic interface to be determined based on the astronomical age scale and the time anchor points.

[0011] Further, before the step S2, the natural gamma logging curve is preprocessed:

[0012] The natural gamma logging curves are processed to remove outliers and detrends in order to eliminate the influence of trend signals and noise signals.

[0013] Further, step S2 includes:

[0014] Multi-window spectral analysis was used to process the natural gamma logging curves to obtain a spectral analysis chart. The dominant peak was determined based on the energy of the peak signal in the spectral analysis chart. The vertical axis of the spectral analysis chart represents the energy of the cycle within the period, and the reciprocal of the horizontal axis represents the formation thickness corresponding to the cycle.

[0015] If the ratio between the formation thicknesses corresponding to the dominant peaks in the spectrum analysis diagram is similar to the ratios of the orbital parameters in the astronomical orbital model, then it is determined that the natural gamma logging curve contains a Mie cyclic signal, and step S3 is continued.

[0016] Furthermore, in step S3, the seismic interface selected as the time anchor point is expressed on the seismic profile as a set of regionally continuous high-amplitude seismic reflection axes in the same direction;

[0017] The seismic interface selected as the time anchor point is determined by a distinct regionally continuous sedimentary-tectonic unconformity.

[0018] Further, step S4 includes:

[0019] From the Laskar2004 model, one of the following is selected as the target curve representing the time domain: eccentricity, slope, or precession.

[0020] Further, step S5 includes:

[0021] The initial correspondence between the natural gamma logging curve and the target curve is determined based on the time anchor point. Starting from the initial correspondence point, the natural gamma logging curve is tuned and corrected to the target curve according to the curve change of the target curve. Based on the point correspondence between the natural gamma logging curve and the target curve, a time-depth conversion table is obtained to reflect the age value corresponding to the depth.

[0022] Determine the time-domain astronomical time scale corresponding to the natural gamma logging curve based on the time-depth conversion table;

[0023] In this system, the horizontal axis of the natural gamma logging curve represents depth, while the horizontal axis of the astronomical timescale represents age.

[0024] Furthermore, step S6 is preceded by:

[0025] Perform time-domain spectral analysis on the astronomical time scale. If the frequency spectrum peak energy corresponding to the orbital parameter selected as the target curve is significantly higher than the frequency spectrum peak energy corresponding to other orbital parameters, then the astronomical time scale obtained in step S5 is determined to be correct, and step S6 is continued; otherwise, return to step S5 to obtain the astronomical time scale again.

[0026] Further, step S6 includes:

[0027] The number of cycles between the seismic interface to be measured and the seismic interface corresponding to the time anchor point is determined based on the astronomical time scale.

[0028] The duration of the cycle is determined based on the selected orbital parameters;

[0029] If the seismic interface to be measured is located below the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression:

[0030] T = T 时间锚点 +m*n

[0031] If the seismic interface to be measured is located above the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression:

[0032] T = T 时间锚点 -m*n

[0033] Where T represents the age of the seismic interface to be determined, T 时间锚点 For the geological age of the co-axial seismic interface of continuous high-amplitude earthquake reflections in the selected region, m represents the time between T and T. 时间锚点 The number of cycles between them, where n is the duration of the cycle.

[0034] The present invention also discloses a computer-readable storage medium storing a computer program for executing the above-described method for determining seismic interface ages based on the Mi cycle.

[0035] The present invention also discloses an electronic device, the electronic device comprising:

[0036] processor;

[0037] Memory used to store the processor's executable instructions;

[0038] The processor is configured to read the executable instructions from the memory and execute the instructions to implement the above-described method for determining seismic interface age based on the Mi cycle.

[0039] The present invention has at least the following beneficial effects:

[0040] This invention uses seismic interfaces with absolute time as time anchors, transforming natural gamma-ray logging curves from the depth domain to the time domain to obtain an astronomical time scale. Based on this astronomical time scale, the age of other seismic interfaces can be determined. Compared to existing technologies, this invention is convenient to implement and offers high analytical accuracy and resolution.

[0041] Other beneficial effects of the present invention will be described in detail in the Detailed Description of the Embodiments section. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0043] Figure 1 This is a flowchart of a seismic interface dating method based on the Michaelis cycle disclosed in a preferred embodiment of the present invention.

[0044] Figure 2 This is the spectrum analysis diagram disclosed in the preferred embodiment of the present invention.

[0045] Figure 3 This is a superimposed diagram of the natural gamma logging curve and the depth domain filtered curve disclosed in a preferred embodiment of the present invention.

[0046] Figure 4 This is a preferred embodiment of the seismic interface feature map disclosed in this invention.

[0047] Figure 5 This is a preferred embodiment of the seismic interface feature map disclosed in this invention.

[0048] Figure 6 These are the target curves for each orbital parameter of the Laskar2004 model disclosed in the preferred embodiment of this invention.

[0049] Figure 7 This is a diagram illustrating the process of tuning and correcting the natural gamma logging curve to the target curve in a preferred embodiment of the present invention.

[0050] Figure 8 This is an astronomical timescale diagram disclosed in a preferred embodiment of the present invention.

[0051] Figure 9 This is an MTM spectrum analysis diagram of the astronomical time scale disclosed in a preferred embodiment of the present invention.

[0052] Figure 10 This is the natural gamma logging curve of the T6-T7 section of well LW13 disclosed in the preferred embodiment of the present invention.

[0053] Figure 11 This is a depth domain spectrum analysis diagram of the GR logging curve of the T6-T7 section of well LW13 disclosed in a preferred embodiment of the present invention.

[0054] Figure 12 This is a superimposed diagram of the preprocessed depth-domain natural gamma logging curve of the T6-T7 section of well LW13 and the filtered curve of ~71 meters, as disclosed in a preferred embodiment of the present invention.

[0055] Figure 13 This is a diagram illustrating the tuning process of the depth domain data sequence of the natural gamma logging curve of well LW13, as disclosed in a preferred embodiment of the present invention, to the long eccentricity astronomical theoretical curve of 405-kyr.

[0056] Figure 14 This is the astronomical time scale tuned to a long eccentricity of 405-kyr as disclosed in the preferred embodiment of the present invention.

[0057] Figure 15 This is a spectral analysis diagram of the natural gamma logging curve of well LW13 disclosed in a preferred embodiment of the present invention, using an astronomical time scale established by long eccentricity period tuning.

[0058] Figure 16 This is a comparison chart of the natural gamma logging curves and astronomical time scales of well LW13 in the depth domain, as disclosed in a preferred embodiment of the present invention.

[0059] Figure 17 This is a comparison chart of the natural gamma logging curves and astronomical time scales of well LH29 in the depth domain, as disclosed in a preferred embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0061] This invention discloses a seismic interface dating method based on the Michaelis cycle, which mainly applies cyclic stratigraphy. Cyclic stratigraphy is based on the fact that the periodic or quasi-periodic changes in the Earth's orbital parameters eccentricity, slope, and precession cause quasi-periodic changes in the Earth's solar radiation, which in turn cause quasi-periodic changes in the Earth's climate system. Ultimately, the climate system affects the sedimentary response under different sedimentary backgrounds.

[0062] like Figure 1 As shown, the present invention includes:

[0063] S1: Obtain the natural gamma logging curve representing the depth domain in the target area.

[0064] In the sedimentary record of strata, certain periodic variations in sediments can reflect the periodic characteristics of paleoclimate. Milankovitch's theory posits that periodic variations in the three parameters of Earth's orbit cause changes in solar radiation, which in turn affect the environmental system, leading to periodic changes in paleoclimate. Therefore, cyclic stratigraphy studies often utilize various proxies recorded in strata that can reconstruct paleoclimate, primarily including: oxygen isotopes, well logging curves, paleomagnetism, carbon isotopes, organic carbon content, stratum thickness, rock type, and color reflectance.

[0065] Natural gamma-ray logging measures the intensity of gamma rays emitted during the nuclear decay of radioactive elements (such as thorium, uranium, and potassium) in rock formations. It also measures the total concentration changes of these radioactive elements within the formation. The intensity of gamma rays is determined by the decay process of these radioactive elements. Natural gamma total (GR) reflects sea-level changes because clay and organic matter particles have a strong ability to adsorb radioactive elements, and these particles are highly sensitive to changes in the sedimentary environment. Since the GR value primarily reflects the properties of the particles, it increases with increasing clay content. Therefore, geologically, it is mainly used to determine the sand-to-mud ratio, median grain size, and sand content. It can also be used for estimating clay content and dividing sequence stratigraphy. Compared to other logging curves, natural gamma-ray logging is the most sensitive to changes in clay content. Furthermore, because clay content is directly related to sedimentary cycles and climate change, natural gamma-ray logging data is a valuable reference indicator for reconstructing the paleoenvironment and paleoclimate of sedimentary basins. This invention uses natural gamma-ray logging curves as a proxy indicator for paleoclimate for cyclic analysis. Natural gamma-ray logging curves have advantages such as small sampling intervals, good continuity, and sensitivity to sea-level changes.

[0066] S2: Based on spectral analysis, determine the signal energy and number of cycles in the natural gamma logging curve, and determine whether the natural gamma logging curve contains Mie cycles based on the signal energy and number of cycles. Although astronomical forces acting on climate can cause rhythmic cycles in sedimentary strata, it cannot be assumed that all cycles in sedimentary strata are Mie cycles, because the sedimentary conditions of strata in different regions are not exactly the same, and even strata in the same region may exhibit different cycles due to different subsequent alterations. Therefore, it is necessary to examine whether the natural gamma logging contains Mie cycle signals.

[0067] Preferably, step S2 specifically includes: processing the natural gamma-ray logging curve using a multi-window spectral analysis method to obtain a spectral analysis diagram, which is used to determine the spectrum of the dominant peak. The vertical axis of the spectral analysis diagram represents the energy of the cycle within the period, and the reciprocal of the horizontal axis represents the formation thickness corresponding to the cycle. If the ratio between the formation thicknesses corresponding to the dominant peak determined by the spectral analysis diagram is similar to the ratio of each orbital parameter in the astronomical orbital model, then it is determined that the natural gamma-ray logging curve contains a Mie cycle signal. Therefore, an astronomical timescale can be established using the natural gamma-ray logging curve.

[0068] like Figure 2 As shown, the horizontal axis of the spectral analysis graph represents frequency (cycles / meter), and the vertical axis represents the relative power spectrum (unitless). A larger vertical value indicates greater energy in that cycle, and the reciprocal of the horizontal axis represents the stratum thickness corresponding to that cycle. Since Mie cycles are generated by astronomical forces acting on the Earth, they possess relative stability; the proportions between their parameters are relatively fixed within a given geological history. Therefore, if depth-domain spectral analysis reveals that the proportions of the stratum thicknesses corresponding to the peaks of the dominant power spectrum exhibit a Milankovitch three-parameter ratio, then this stratum can be considered to be influenced by a Mie cycle. It is worth noting that complex and diverse geological conditions, such as sedimentary phenomena like diagenesis, can affect the preservation of Milankovitch cycles in strata. Therefore, if the proportions between the dominant frequencies of the analyzed main peaks differ somewhat from the relatively fixed proportions of the three parameters of the Mie cycle, the stratum is still considered to be influenced by a Mie cycle.

[0069] This invention uses the Multitaper Method (MTM) to determine the spectrum of the dominant peak and employs digital filtering to extract specific peak frequencies. Specifically, this invention uses bandwidth filtering. The parameters of bandwidth filtering include the center frequency and the bandwidth. This invention selects the center frequency as the frequency corresponding to the dominant peak and the bandwidth as the frequency range that best covers the spectral peak range. Selecting a center frequency and bandwidth means extracting information from a certain width of the spectral peak corresponding to that center frequency. When selecting the bandwidth, it should cover as much of the signal as possible from the selected dominant peak, and should also appropriately cover both sides, but should not be too large.

[0070] like Figure 2 and Figure 3 As shown, by analyzing the proportional relationship between the peaks in the depth domain spectrum and combining it with the formation thickness corresponding to 405 kyr calculated from the average deposition rate, it is considered that the 71-meter section (with a peak frequency of 0.014m) in this data segment... -1 The peak value represents a long eccentricity period of 405 kyr and 18 meters (0.056 m).-1 () represents a short eccentricity period of 100 kyr, 7.1 meters (0.14 m). -1 ) represents the slope period, 3.5 meters (0.28m) -1 The ) represents the precession cycle. It can be seen that even though the amount of data in this selected section is small and the formation thickness is not large, it can still show a dominant peak frequency that is almost the same as the whole, and the peak values ​​of the slope cycle and eccentricity cycle are more obvious. Therefore, it can be considered that the formation interpreted by drilling in this region contains signals of eccentricity, slope and precession cycle of Mie cycles.

[0071] S3: Select a set of high-amplitude continuous seismic interfaces with definite age and depth in the target area as time anchors. The geological age of the seismic interfaces selected as time anchors is determined by the apocryphal surface of calcareous nannofossils and the proto-surface surface of planktonic foraminifera. The specific method is based on existing technology in this field and will not be elaborated here.

[0072] The seismic interface selected as the time anchor point in this invention is represented on the seismic profile as a set of continuous, high-amplitude seismic reflection axes in the same direction. The seismic interface selected as the time anchor point must not only possess absolute time but also be easily traceable. For example... Figure 4 and Figure 5 As shown, T6, as a regional tectonic unconformity, appears as a continuous set of strong-amplitude seismic reflection phase axes on the seismic profile. This characteristic of the T6 seismic reflection phase axes makes the T6 seismic interface easy to trace, minimizing the possibility of interpretation errors. Therefore, the seismic interface T6 can be chosen as a time anchor point, and its depth location is considered accurate for well logging, with a definite corresponding geological age.

[0073] S4: Select the corresponding orbital parameters from the astronomical orbital model as the target curve representing the time domain. An astronomical orbital model is a model of the changes in the three parameters of Earth's orbit, established based on the influence of inner-orbiting planets on these parameters. Laskar2004 is one such representative astronomical orbital model.

[0074] Specifically, the orbital parameters selectable from the Laskar 2004 model include eccentricity, slope, precession, and solar irradiance. Commonly used models for astronomical orbital parameters include Berger 1978, Laskar 1993, Laskar 2004, and Laskar 2010. Among these, the stable Cenozoic Laskar 2004 and the later Laskar 2010 models best reflect the changes in Earth's orbital parameters over geological history. Therefore, the theoretical astronomical orbital parameter model used in this invention is Laskar 2004. The Laskar 2004 model can be used to calculate the changes in three parameters: eccentricity, slope, and precession. See also... Figure 6The three target curves a, b, and c represent the cyclic curves corresponding to the eccentricity, slope, and precession in the range of 16000Ka-31000Ka, which are the target curves.

[0075] Studies have shown that long eccentricity is the most stable during geological history and is therefore commonly used for astronomical tuning. In this embodiment, by analyzing the depth-domain spectral analysis, the formation thickness corresponding to the dominant peak of the natural gamma ray logging curve is approximately 60-70 meters. The average deposition rate can be estimated using the rough age of the drilling sequence boundary and the formation thickness. Dividing the formation thickness corresponding to the dominant peak by the average deposition rate yields the time required to deposit 60 meters of formation, which is calculated to be around 400 kyr. Therefore, the eccentricity signal can be considered the most prominent. In summary, this embodiment of the invention uses a 405 kyr long eccentricity curve as the target curve for tuning.

[0076] S5: Determine the initial correspondence between the natural gamma logging curve and the target curve based on the time anchor point, and use the initial correspondence as the starting point to tune and correct the natural gamma logging curve to the target curve according to the curve change of the target curve, so as to obtain an astronomical age scale that reflects the correspondence between the depth domain and the time domain.

[0077] Specifically, the initial correspondence between the natural gamma-ray logging curve and the target curve is determined based on time anchor points. Starting from this initial correspondence, the natural gamma-ray logging curve is tuned and corrected to the target curve according to its curve variations. Based on the point correspondence between the natural gamma-ray logging curve and the target curve, a time-depth conversion table is obtained to reflect the corresponding age values ​​for the depth. Based on this time-depth conversion table, an astronomical age scale reflecting the time domain data corresponding to the natural gamma-ray logging curve is determined. In this table, the horizontal axis of the natural gamma-ray logging curve represents depth, and the horizontal axis of the astronomical age scale represents age.

[0078] like Figure 7 and Figure 8 As shown, this embodiment uses the depth-domain filtering curve as a reference and corrects the logging curve to the Laskar 2004 theoretical curve according to the cyclicity change. This process is called astronomical tuning, which needs to be repeatedly verified until the spectrum analysis diagram of the obtained astronomical age scale is closest to the theoretical curve (that is, the frequency spectrum peak energy of the applied tuning orbital parameter is concentrated and much higher than the surrounding values, and the corresponding frequency spectrum peaks of other orbital parameters are also shown). After astronomical tuning, a time-depth conversion table can be obtained (see Table 1).

[0079] Table 1

[0080] LW13 LW13 Depth (m) Time (kyr) Slope (40 kyr) Depth (m) Time (kyr) Slope (40 kyr) 3399.42 24989.88 1O 3581.09 25913.49 O24 3406.11 25027.41 2O 3588.39 25953.08 O25 3411.50 25065.98 3O 3595.14 25993.65 O26 3419.30 25107.25 4O 3602.56 26032.65 O27 3430.13 25147.67 5O 3608.31 26071.83 O28 3438.84 25189.09 6O 3614.99 26110.80 O29 3444.87 25225.71 7O 3620.88 26151.27 O30 3453.72 25267.26 8O 3627.19 26191.36 O31 3460.89 25310.81 9O 3635.25 26231.02 O32 3470.08 25357.12 10O 3641.31 26267.77 O33 3477.77 25390.97 11O 3646.97 26307.93 O34 3484.75 25429.57 12O 3652.88 26349.86 O35 3491.61 25476.01 13O 3659.59 26386.63 O36 3497.48 25515.78 14O 3665.74 26426.18 O37 3507.79 25558.37 15O 3673.26 26470.39 O38 3515.03 25593.84 16O 3680.63 26506.96 O39 3523.32 25638.00 17O 3689.27 26549.81 O40 3529.70 25675.98 18O 3697.65 26588.41 O41 3538.18 25713.77 19O 3704.74 26627.00 O42 3545.92 25757.13 20O 3711.88 26673.49 O43 3556.47 25795.03 21O 3719.16 26708.67 O44 3564.39 25833.94 22O 3728.61 26747.33 O45 3572.95 25874.90 23O 3741.01 26792.27 O46

[0081] In Table 1, each depth value corresponds to a time value. The depth-time conversion table can be used to convert depth domain data into time domain data, which is the astronomical tuning scale.

[0082] S6: Determine the age of the seismic interface to be measured based on an astronomical timescale. Details are as follows:

[0083] The number of cycles between the seismic interface to be measured and the seismic interface corresponding to the time anchor point is determined based on the astronomical chronological scale; the duration of the cycle is determined based on the selected orbital parameters; if the seismic interface to be measured is located below the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression:

[0084] T = T 时间锚点 +m*n (1)

[0085] If the seismic interface to be measured is located above the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression:

[0086] T = T 时间锚点 -m*n (2)

[0087] Where T represents the age of the seismic interface to be determined, T 时间锚点 For the geological age of the co-axial seismic interface of continuous high-amplitude earthquake reflections in the selected region, m represents the time between T and T. 时间锚点 The number of cycles between them, where n is the duration of the cycle.

[0088] In this invention, prior to step S2, preprocessing of the natural gamma ray logging curve is included. This preprocessing technique aims to suppress unwanted signals and highlight the Mie cyclotron signal. Specifically, the natural gamma ray logging curve undergoes outlier removal and detrending processing to eliminate the influence of trend signals and noise signals.

[0089] Outliers are isolated values ​​that significantly deviate from the overall trend of other values. Outliers can arise from measurement errors or random errors caused by chance. While outliers have little impact on the overall signal mean, they can significantly raise the background energy of the power spectrum, severely affecting the accuracy of spectral analysis.

[0090] After removing outliers, trend removal is also necessary. Although well logging data and other data collected from field outcrops are depth-domain data, there is usually a correlation between deposition time and deposition thickness. That is, the values ​​may increase or decrease with increasing depth. This type of data is called non-static data. Non-static data will generate a strong low-frequency signal during spectral analysis, affecting the accuracy of the spectral analysis results. Therefore, trend removal methods are needed to eliminate linear trends.

[0091] In this invention, the astronomical time scale obtained in step S5 needs to be verified before step S6. Specifically, a time-domain spectral analysis is performed on the astronomical time scale. If the frequency peak corresponding to the orbital parameter selected as the target curve is significantly higher than the frequency peak energy corresponding to other orbital parameters, then the astronomical time scale obtained in step S5 is determined to be correct, and step S6 continues; otherwise, step S5 is returned to obtain the astronomical time scale again.

[0092] like Figure 9 As shown, after astronomical tuning, the astronomical age scale of a single well can be obtained. At this point, it is necessary to verify whether the tuning process is correct. The verification standard is to analyze whether the spectral energy of the 405kyr, 100kyr, and 41kyr periods is concentrated and significantly higher than the energy of the background noise to judge whether the tuning result is accurate.

[0093] The present invention discloses the following embodiments for detailed description.

[0094] Example 1

[0095] This embodiment establishes an astronomical timeline based on the LW13 well in the measured area. According to the LW13 well sequence interpretation, a 1500-meter-thick stratum (3046-4482 meters) was selected for cyclic stratigraphic analysis.

[0096] The logging curves of well LW13 show significant cyclicity and a relatively stable depositional rate. Therefore, well LW13 will not be segmented; instead, it will be analyzed as a whole for cyclic formation analysis. (See also...) Figure 10 The natural gamma-ray logging curves for the T6-T7 section of well LW13, shown, exhibit good rhythmicity within a formation approximately 1436 meters thick. (For example...) Figure 11 As shown in the figure, the values ​​above the dominant peaks represent the frequencies corresponding to these peaks, and the values ​​in parentheses represent the formation thickness corresponding to these frequencies. The depth-domain spectral analysis reveals multiple dominant peaks, including 0.005, 0.014, 0.025, 0.033, and 0.056, with the 0.014 (71 m) peak being the most prominent. Based on the known thickness of the divided drilling sequence and the approximate deposition time, the 0.014 peak is estimated to correspond to a long eccentricity period of 405 kyr. The information of the 0.014 dominant peak is extracted using a bandpass filter, with a selected center frequency of 0.014 and a bandwidth of 0.004. The preprocessed natural gamma logging curve is overlaid with the filtered curve to check if the selected parameters for the bandpass filter are correct. It can be seen that the filtered curve extracted by the two parameters selected in this invention contains the main cycle information of the logging curve, and the cycle period is obvious (see...). Figure 12 In the figure, a represents the preprocessed depth domain data, and b represents the 71-meter filtered curve.

[0097] By using long eccentricity astronomical tuning, a time-depth conversion table as shown in Table 2 can be established, where one depth corresponds to one time, and the interval between two time points is one long eccentricity period.

[0098] Table 2

[0099]

[0100]

[0101] By comparing the depth domain data of LW13 well with the theoretical long eccentricity curve according to the cyclic variation (e.g.) Figure 13 As shown), a temporal depth relationship was established. Figure 14 As shown, Figure 14 In the table, 'm' represents the long eccentricity tuned chronology scale of well LW13, and 'n' represents the 405kyr long eccentricity filtered curve. The depth-domain logging curve can be converted to a long eccentricity astronomical tuned chronology scale using a time-depth conversion table. This tuning process requires repeated verification until the spectrum of the obtained time-domain astronomical chronology scale most closely approximates the theory. (See Table 2 and...) Figure 14 As shown, the depth of the T6 interface in well LW13 is 3064 meters, with a geological age of 23.09 Ma (23096 kyr), and the depth of the T7 interface is 4482 meters. The area between the T6 and T7 interfaces contains approximately 20 long eccentricity cycles (E2 to E22). Therefore, the following can be calculated using the above formula (1):

[0102] T7=T6+0.405Ma*20=31.1Ma (3)

[0103] That is, the geological age of the T7 interface is 31.1 million years.

[0104] Finally, the astronomical time scale needs to be verified through time-domain spectral analysis. MTM spectral analysis can be used not only to analyze whether depth-domain data exhibits typical cyclicity, but also to verify the accuracy of the tuned astronomical time scale. The verification standard is to perform spectral analysis on the tuned astronomical time scale; if the dominant peak energy is significantly higher than the surrounding peaks, the tuning result is considered correct. For example... Figure 15 As shown in the spectrum of the astronomical age scale of well LW13, the main peak corresponding to the 405 kyr long eccentricity cycle is very prominent, and the 100 kyr short eccentricity cycle is also shown. Therefore, it can be considered that the tuning results are consistent with reality, and the established astronomical scale is correct. Based on the above analysis, it can be comprehensively determined that the astronomical age scale obtained by astronomical tuning of the natural gamma logging curve of well LW13 is reliable.

[0105] Example 2

[0106] This invention is based on Figure 4 and Figure 5 Taking T7 as an example, the T7 interface represents the seismic boundary, which is a set of regional unconformities. It represents the end of regional rifting (the end of the rift stage) and the beginning of marine sedimentation in the BY depression (the beginning of the subsidence stage). The T7 unconformity can divide the basin into two geological units, upper and lower.

[0107] This invention employs natural gamma-ray logging data from two wells as alternative indices for cyclic stratigraphy analysis, establishing an astronomical tuning timescale for the study section between the T6 (time anchor point) and the T7 interface. Specifically, using spectral analysis, assuming the T6 seismic interface is region-wide comparable and represents the Oligocene / Miocene world line (age 23.03 Ma), the astronomical timescale established from the natural gamma-ray logging data of well LW13 yields a corresponding age of 31.1 Ma for the T7 seismic sequence interface at 4482 meters. Since this embodiment uses a 405 kyr long eccentricity for tuning, the filtered curve shows that the duration of one cycle is 405 kyr. There are 20 405 kyr cycles from T6 to T7, therefore the calculated age of the T7 sequence interface is 31.1 Ma. (See [link to relevant documentation]). Figure 16 Furthermore, given that the thickness between the T6 and T7 interfaces in well LW13 is 1436 meters and the formation deposition lasted for 8.07 Ma, this drilling can be considered to have revealed the formation completely and in detail. Preliminary observation using natural gamma-ray logging does not reveal any significant depositional discontinuities. Similarly, as... Figure 17 As shown, well LH29 reveals the T4-T7 period. The T7 seismic interface calculated from this well location is also 31.1 Ma, indicating that at least within the BY Depression, the age of the T7 interface should be 31.1 Ma.

[0108] It is worth mentioning that the abbreviations in the disclosure of this invention, such as BY, LW, LH, etc., are used to refer to the regions, projects, etc. involved in each embodiment.

[0109] The present invention also discloses a computer-readable storage medium storing a computer program for executing the seismic interface dating method based on the Mi cycle described above.

[0110] The present invention also discloses an electronic device comprising: a processor; and a memory for storing executable instructions of the processor. The processor is configured to read the executable instructions from the memory and execute the instructions to implement the seismic interface dating method based on the Mie cycle described above.

[0111] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining seismic interface dates based on the Mie cycle, characterized in that, include: S1: Obtain the natural gamma logging curve representing the depth domain in the target area; S2: Determine the signal energy and number of cycles of the natural gamma logging curve based on spectrum analysis, and determine whether the natural gamma logging curve contains Mie cycles based on the signal energy and number of cycles; S3: Select a set of high-amplitude continuous seismic interfaces with a defined age and depth in the target area as time anchors; S4: Select the corresponding orbital parameters from the astronomical orbital model as the target curve representing the time domain; S5: Determine the initial correspondence between the natural gamma logging curve and the target curve based on the time anchor point, and tune the natural gamma logging curve to the target curve according to the curve change of the target curve, based on the initial correspondence position, to obtain a time-depth conversion table that reflects the correspondence between the depth domain and the time domain; determine the astronomical age scale based on the continuous time-depth conversion table. S6: Determine the age of the seismic interface to be measured based on the astronomical time scale and time anchor points, as follows: The number of cycles between the seismic interface to be measured and the seismic interface corresponding to the time anchor point is determined based on the astronomical chronological scale; the duration of the cycle is determined based on the selected orbital parameters; if the seismic interface to be measured is located below the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression: T=T 时间锚点 +m*n (1) If the seismic interface to be measured is located above the seismic interface corresponding to the time anchor point, the age of the seismic interface to be measured is determined by the following expression: T=T 时间锚点 -m*n (2) Where T represents the age of the seismic interface to be determined, T 时间锚点 For the geological age of the co-axial seismic interface of continuous high-amplitude earthquake reflections in the selected region, m represents the time between T and T. 时间锚点 The number of cycles between them, where n is the duration of the cycle.

2. The seismic interface dating method based on the Mie cycle according to claim 1, characterized in that, Before step S2, the natural gamma logging curve is preprocessed: The natural gamma logging curves are processed to remove outliers and detrends in order to eliminate the influence of trend signals and noise signals.

3. The seismic interface dating method based on the Mi cycle according to claim 2, characterized in that, Step S2 includes: Multi-window spectral analysis was used to process the natural gamma logging curves to obtain a spectral analysis chart. The dominant peak was determined based on the energy of the peak signal in the spectral analysis chart. The vertical axis of the spectral analysis chart represents the energy of the cycle within the period, and the reciprocal of the horizontal axis represents the formation thickness corresponding to the cycle. If the ratio between the formation thicknesses corresponding to the dominant peaks in the spectrum analysis diagram is similar to the ratios of the orbital parameters in the astronomical orbital model, then it is determined that the natural gamma logging curve contains a Mie cyclic signal, and step S3 is continued.

4. The seismic interface dating method based on the Mi cycle according to claim 1, characterized in that, In step S3, the seismic interface selected as the time anchor point is expressed on the seismic profile as a set of regionally continuous high-amplitude seismic reflection axes in the same direction; The seismic interface selected as the time anchor point is determined by a distinct regionally continuous sedimentary-tectonic unconformity.

5. The seismic interface dating method based on the Mi cycle according to claim 1, characterized in that, Step S4 includes: From the Laskar2004 model, one of the following is selected as the target curve representing the time domain: eccentricity, slope, or precession.

6. The seismic interface dating method based on the Mi cycle according to claim 1, characterized in that, Step S5 includes: The initial correspondence between the natural gamma logging curve and the target curve is determined based on the time anchor point. Starting from the initial correspondence point, the natural gamma logging curve is tuned and corrected to the target curve according to the curve change of the target curve. Based on the point correspondence between the natural gamma logging curve and the target curve, a time-depth conversion table is obtained to reflect the age value corresponding to the depth. Determine the time-domain astronomical time scale corresponding to the natural gamma logging curve based on the time-depth conversion table; In this system, the horizontal axis of the natural gamma logging curve represents depth, while the horizontal axis of the astronomical timescale represents age.

7. The seismic interface dating method based on the Mie cycle according to claim 1, characterized in that, The preceding steps in step S6 include: Perform time-domain spectral analysis on the astronomical time scale. If the frequency spectrum peak energy corresponding to the orbital parameter selected as the target curve is significantly higher than the frequency spectrum peak energy corresponding to other orbital parameters, then the astronomical time scale obtained in step S5 is determined to be correct, and step S6 is continued; otherwise, return to step S5 to obtain the astronomical time scale again.

8. A computer-readable storage medium storing a computer program for performing the method of any one of claims 1-7.

9. An electronic device, the electronic device comprising: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method of any one of claims 1-7.

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