CN114488305B - A fine calibration method for geological horizons of seismic data in new exploration areas without wells - Google Patents

Abstract

The invention discloses a method for finely calibrating the geological horizon of seismic data in a new exploration area without a well, which realizes the work of finely calibrating the seismic geological horizon. Including: S01: Select the field standard profile survey points and sort them; S02: Select the seismic-geological horizon comparison trace of the seismic profile; S03: Find the seismic spectrum and main frequency of the seismic profile; S04: Find the thickness and distinguishable thickness of the seismically detectable stratum Formation thickness; S05: Obtain standard profile measurement data of field outcrops; S06: Measure rock acoustic velocity and density data; S07: Obtain seismic formation thickness; S08: Obtain standard layer reflection coefficient series; S09: Obtain seismic wavelets; S10 : Calculated synthetic seismic records; S11: Geological interface calibration.

Description

A fine calibration method for geological horizons of seismic data in new exploration areas without wells

technical field

The invention relates to the technical field of conventional and unconventional oil and gas exploration, and relates to a fine calibration method for seismic data geological horizons in new exploration areas without wells, which is especially suitable for unconventional oil and gas such as natural gas hydrate, deep basin gas, shale oil and gas and other new energy sources In the early stage of exploration, there is no drilling and logging data, or oil and gas exploration fields in deep systems and deep water areas.

Background technique

In the process of conventional and unconventional oil and gas exploration and development, the calibration of geological horizons to seismic data is the basic work of seismic interpretation, but its accuracy determines the reliability of seismic interpretation, and will directly affect subsequent resource evaluation and drilling. Therefore, horizon calibration of seismic data is also the core work.

At present, there are two methods for calibrating geological horizons to seismic data: the hat method and the well-seismic comparison method. The hat-wearing method is to collect ground geological data by establishing a structural geological model, mainly including the structural characteristics and lithological characteristics of the exposed strata, and draw a lithological section of the same scale as the seismic section, and integrate it with the seismic section, which is convenient for interpreters. Understanding and understanding of tectonic geological models. The well-seismic comparison method uses the convolution of drilling data to calculate the synthetic seismic records and calibrate them on the actual seismic records. The comparison markers for both are seismic records, and they are compared within the same dimension range. The comparison process is more intuitive and the conclusion is reliable. higher.

The two methods have their own scope of application, and both have certain shortcomings. The former is mainly used in the initial stage of unconventional new energy exploration such as natural gas hydrate, deep basin gas, and shale oil. The exploration area has not yet been drilled or the drilling is sparse, and the complete stratigraphic sequence in the study area cannot be provided. Seismic data interpretation level and work experience are highly subjective. The latter conclusion is reliable, but requires high data type and accuracy, and is widely used in conventional oil and gas exploration in mature blocks with rich drilling, logging, logging and other data, but for seismic data interpretation in new exploration areas without drilling, due to In the absence of drilling data, it is useless to use the logging acoustic and density data to make synthetic records.

How to achieve accurate seismic-geological horizon calibration in the aforementioned new exploration area without drilling is a technical problem in oil and gas exploration, especially in the process of unconventional oil and gas exploration. is a good choice, but there is only one article doing research in this area. Authors Guo Qiuxia, Li Xiaogang, Chen Jingtan, etc. published a paper entitled "Calibrating Seismic Horizons by Simulating Synthetic Seismic Records Based on Outcrop Data—Taking the Kuh-e-Gugird Anticline in the Garmsar Block as the Example" article published on March 15, 2009. This journal document mainly discloses: in the absence of logging data in the study area, using the geological profile measured in the field, referring to the velocity and density data of the adjacent area, simulating the synthetic seismic record, the Kuh-e-Gugird passing through the Garmsar block is analyzed. The seismic horizon calibration of the seismic data of the anticline is carried out, and the results show that the two can be well matched. However, there are still three problems or defects in this method:

(1) Data depends on drilling data in adjacent areas. In this method, the velocity and density data used in the no-well calibration come from the drilling data of the adjacent work area. If there is no drilling in the adjacent area of the new exploration area, the key information such as the thickness and density of the deeply buried underground formation cannot be obtained, and the data cannot be used directly. method to calibrate seismic data.

(2) Whether the cited data points are in the same sedimentary facies belt as the seismic data to be calibrated is not considered. In this method, the velocity and density used in the production of synthetic seismic records come from drilling data in adjacent areas, and are affected by changes in sedimentary facies belts, burial depth and compaction. In this case, the adjacent area data can be used directly, but when the depositional backgrounds of the two do not match, due to the simultaneous out-of-phase, the strata in the same period will be different in rock types and compositions, and the propagation speed of seismic waves will be different, sometimes even if the same Due to the different structures of rock types due to the influence of burial depth, the wave velocity will also change within a certain range. Therefore, the velocity and density change greatly, and there will undoubtedly be large errors when directly used to make synthetic seismic records and compared with seismic data. Even if there is no drilling data in the adjacent area, the method cannot be applied to the calibration of seismic geological horizons;

(3) The influence of lateral variation of formation thickness on synthetic seismic records is not considered. This method does not take into account the lateral variation of the stratum, but is actually affected by factors such as water depth, burial depth, and structural location during deposition (like the lateral variation of stratum thickness caused by the depositional structure). There is thickness variation, and there is also a big problem in directly using outcrop thickness instead of underground thickness.

If we can solve the problems of lack of logging speed and accuracy, and fully consider the influence of formation thickness, we can realize the problem of seismic horizon calibration in the new exploration area with no drilling data for reference in adjacent areas, and at the same time eliminate the problem to the greatest extent possible. The multi-solution problem of seismic geological horizon calibration can improve the accuracy of geological horizon calibration.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a method for finely calibrating the geological horizons of seismic data in a new exploration area without wells, so as to realize the precise work of calibrating the seismic geological horizons.

The object of the present invention is achieved in this way:

A method for finely calibrating seismic data geological horizons in a new exploration area without wells, comprising the following steps:

S01: Select field standard profile survey points and sort them;

S02: Select the seismic-geological layer comparison trace of the seismic profile;

S03: Obtain the seismic spectrum and main frequency of the seismic profile;

S04: Obtain the thickness of the seismically detectable formation and the thickness of the distinguishable formation;

S05: Obtain standard profile measurement data of field outcrops;

S06: Measure rock acoustic velocity and density data;

S07: Obtain the thickness of the seismic formation;

S08: Obtain the standard layer reflection coefficient series;

S09: Obtain seismic wavelet;

S10: Calculate synthetic seismic records;

S11: Geological interface calibration.

Further, the step S01 includes:

S011: Superimpose the plane position of the seismic profile survey line and the field outcrop profile position on the relevant basic geological map through the geodetic coordinate system to form a superimposed map;

S012: On the superimposed map, follow the principle of "close to the survey line, consistent facies zone, consistent lithology", select the outcrop point of the target stratum (that is, the stratigraphic sequence that needs to be calibrated on the seismic section) on the geological map, and press " According to the above principles, select multiple outcrop points to form a field stratigraphic point set corresponding to the proposed calibration time window of the seismic profile;

S013: Sort the selected outcrop points from new to old, and connect them to form a field standard profile survey point with complete stratigraphy.

Further, the step S02 includes:

The seismic stratigraphic frame interface is obtained by tracking the event axis with strong contrast amplitude energy and good continuity by using the vertical strength and weak relationship of the event axis of the seismic section and the contact relationship of the event axis, including upper overshoot, lower overshoot, and truncation;

According to the regional sedimentary facies belt, the selected outcrop points are connected to the seismic profile by the same facies belt translation line, the line intersects with the plane projection line of the seismic profile, and the midpoint of the line connecting the intersections of the vertical lines of the seismic profile is drawn, from the midpoint to the two sides Extend, select 1000 traces with stable thickness of the seismic stratigraphic frame, as the seismic comparison trace of the seismic profile, to ensure that the rock layers at the seismic comparison trace and the rock layers of the field profile have the consistency of the deposition sequence, and ensure that the thickness of the rock layers at the two points has a linear relationship. , the velocity and density parameters of rocks are comparable.

Further, the step S03 includes:

Select the seismic waves with time windows greater than two periods at the top, middle, and bottom of the seismic profile contrast trace to carry out fast Fourier transform, and obtain the seismic time domain rematch spectrum at the top, middle, and bottom. If the rematch spectrum has jump waves, select it again Expand the time window until the spectrum is stable, and obtain the seismic spectrum;

On the seismic rematch spectrum, a horizontal straight line is drawn with the -20DB signal as the boundary. The line has two intersection points with the seismic spectrum curve: the highest frequency f _max , the minimum frequency f _min , and the main seismic frequency f _avg is:

The step S04 includes:

Use seismic processing to pick up the final velocity spectrum, pick the top, middle and bottom velocities v;

Obtain the seismically detectable stratum thickness of the top, middle, and bottom respectively, and then take the average value as the stratum detectable thickness of the seismic data;

Obtain the seismically distinguishable formation thickness of the top, middle and bottom respectively, and then take the average value as the distinguishable formation thickness of the seismic data;

The step S05 includes:

Investigate field profiles in sequence;

During the reconnaissance process, while observing the lithology and stratification, record the thickness of each lithologic stratum. The thickness recording range is not greater than the detectable stratum thickness of the earthquake. .

Further, the step S06 includes:

Use the data measured in the field to compile a comprehensive histogram of lithology;

Measure the density data of the sample, and then calculate the longitudinal wave velocity data V _sample of the sample through the following formula:

V _sample =(ρ _sample ×3.2051) ^4.10257 ;

Add an empty channel next to the lithologic column of the lithologic comprehensive histogram, and record the density data and P-wave velocity data of the sample in the empty channel;

The density data and the longitudinal wave velocity data scatter points are respectively combined to form a velocity data polyline.

Further, the step S07 includes:

The lithology is grouped according to the velocity difference, and the smallest unit of the grouping is the lithology group;

Pick up the thickness of the stratum frame respectively, and use the velocity data processed by the seismic data to calculate the thickness of the frame stratum;

Using the method of wearing hat and lithologic group seismic facies analysis, combined with the comprehensive lithologic histogram, the age of the seismic frame strata was roughly determined;

According to the contact relationship of the seismic stratigraphic frame layer extending to the outcrop point, the method of sedimentary trend comparison is adopted, the thickness h _k of the frame layer is compared with the lithological group h _z measured in the field, and the thickness contrast coefficient K of the lithological group is obtained;

Calculate the mean value _ka of the lithological group thickness contrast coefficient;

Use the formula:

h _z =h _k *k _a

The thickness of the lithologic group is obtained as the true stratigraphic thickness of the lithologic group. At this time, the thickness is equivalent to the lithologic combination at the comparison point of the seismic section, and the thickness of the stratum is consistent.

Further, the step S08 includes:

According to the lithological group data, the following formula is used to obtain the reflection coefficient sequence of the interface between the lithological groups:

In the formula, Ri is the reflection coefficient of the interface formed by lithologic group _i and lithologic group i+1, ρ _i , vi and ρ _{i +1} , vi ₊₁ are the density and acoustic velocity of i and i+1, respectively .

Further, the step S09 includes:

Select the rake wavelet and use the main frequency f _avg of the earthquake to calculate the seismic wavelet

where A(t) is the amplitude of the Rake wavelet at the reflection interface, f _avg is the dominant frequency of the earthquake, and t is the time relative to the center point of the convolution in the time window.

Further, the step S10 includes:

According to the velocity and thickness data of lithology grouping, time-depth conversion is carried out. During the conversion process, the corresponding relationship between time, depth, lithology and geological stratification needs to be recorded at the same time, and a basic data comparison reference table is established. Compared with the time window value of , select the maximum value as the calculation time window;

The synthetic seismic record data S(t) is obtained by convolution of the lithological group reflection sequence and seismic wavelet in the corresponding time domain, and accumulated in the calculation time window;

S(t)=R _i (t)*A(t)

In the formula, S(t) is the synthetic seismic record data, i is the lithological group number, R _i (t) is the reflection coefficient of the interface formed by the lithological group i and the lithological group i+1, and A(t) is the reflection interface The rake wavelet amplitude energy, t is the time relative to the convolution center point in the time window.

Further, the step S11 includes:

Draw a waveform diagram of the synthetic seismic record data in the coordinate system, which is a synthetic seismic record, which must meet the following requirements: the horizontal direction is the amplitude value, the vertical direction is the time, and the time series decreases in turn in the vertical direction;

Adjust the longitudinal time scale of the synthetic seismic record to be consistent with the seismic profile, and adjust the maximum lateral amplitude to be consistent with the seismic profile, superimpose it on the seismic profile, first use the hat method to roughly compare and calibrate the axis with the strongest reflected energy, and then move the synthetic seismic record up and down. , so that the energy relationship between the synthetic seismic record and the actual seismic record is consistent with the longitudinal wave group, and the correlation reaches the maximum. At this time, the seismic record obtained from the field data matches the actual profile;

Using the basic data to compare the corresponding relationship between time, lithology and geological stratification in the reference table, the geological stratification interface is calibrated on the seismic section to realize the final seismic-geological interface calibration.

Due to the adoption of the above technical scheme, the method of the present invention is applied to the seismic interpretation work in which drilling data is still lacking in the new exploration area in the oil and gas exploration process. , to realize the calibration of fine seismic geological layers.

Advantages of the present invention include:

(1) The seismic contrast trace in the seismic profile is selected by means of the translation of the sedimentary facies zone, so that the field measured section and the seismic contrast trace are comparable, and the stratum thickness and the seismic contrast trace have a linear relationship. Thickness data can more accurately calculate the thickness of seismic detection;

(2) The rock samples are obtained from the field measured section, the rock velocity and density data are actually measured in the laboratory, and the thickness can be distinguished and detectable by the earthquake to reduce the number of sampling points. In addition, the density data is used to inversely calculate the longitudinal wave velocity data, which simplifies the method of the present invention. Not only can it reduce the difficulty of operation and greatly reduce the cost of actual measurement, but also the data obtained are more accurate than the logging curves of other blocks;

Description of drawings

Fig. 1 is the method flow chart of the present invention;

Figure 2 is a schematic diagram of the seismic profile survey line and the location of geological outcrops in the field;

Figure 3 is a schematic diagram of the seismic profile of line A (the white frame range in the figure is the selected contrast seismic trace);

Figure 4 is a schematic diagram of the superposition of the synthetic seismogram and the seismic profile seismic-geological horizon correlation trace.

Detailed ways

The implementation process of the method of the present invention is shown in flowchart 1, which mainly includes 11 steps, which are:

S01: Select field standard profile survey points;

S02: Select the seismic-geological layer comparison trace of the seismic profile;

S03: Obtain the seismic spectrum and main frequency of the seismic profile;

S04: Obtain the seismically detectable and distinguishable formation thickness;

S05: Obtain standard profile measurement data of field outcrops;

S06: Laboratory measurement of rock acoustic velocity and density data;

S07: Obtain the thickness of the seismic formation;

S08: Obtain the standard layer reflection coefficient series;

S09: Obtain seismic wavelet;

S10: Calculate synthetic seismic records;

S11: Geological interface calibration.

The specific implementation process is as follows:

Step S01 (selecting field standard profile survey points) includes:

(1) Superimpose the plane position of the seismic profile survey line and the field outcrop profile position on the relevant basic geological map through the geodetic coordinate system to form a superimposed map;

(2) On the superimposed map, following the principle of "close to the survey line, consistent facies zone, and consistent lithology", select the outcrop point of the target stratum (that is, the stratigraphic sequence that needs to be calibrated on the seismic section) on the geological map, and press "Group" or even "segment" as a unit, select multiple outcrop points according to the above principles, so as to form a field stratigraphic point set corresponding to the proposed calibration time window of the seismic profile;

(3) Arrange the selected outcrop points in the order from new to old, and connect them to form a field standard profile survey point with complete stratigraphy;

Step S02 (selecting seismic profile seismic geological layer comparison trace) includes:

(1) Using the longitudinal strength relationship of the seismic profile event axis and the contact relationship of the event axis, including overshooting, overshooting, and truncation, tracking the event axis with strong contrast amplitude energy and good continuity to obtain the seismic stratigraphic frame interface;

(2) According to the regional sedimentary facies belt, the selected outcrop points are connected to the seismic profile by the same facies belt translation, and the line intersects with the plane projection line of the seismic profile, and the midpoint of the line connecting the vertical lines of the seismic profile is drawn. The points are extended to both sides, and 1000 traces with stable thickness of the seismic stratigraphic frame are selected as the seismic comparison traces of the seismic section.

This step is one of the core steps of the present invention, which is characterized in that the comparison trace of the seismic profile is searched by means of the translation of the sedimentary facies zone, which can ensure that the rock formation at the seismic comparison trace and the rock formation of the field profile have the consistency of the deposition sequence, so that the It is ensured that the thickness of the rock layer at the two points has a linear relationship, and the velocity and density parameters of the rock are comparable.

Step S03 (obtaining the seismic spectrum and main frequency of the seismic profile) includes:

(1) Select seismic waves with time windows greater than two periods at the top, middle, and bottom of the seismic profile contrast trace to carry out fast Fourier transform, and obtain the seismic time domain rematch spectrum of the three parts. Choose to expand the time window until the spectrum is stable, and obtain the seismic spectrum;

(2) On the seismic rematch spectrum, a horizontal straight line is drawn with the -20DB signal as the boundary. There will be two intersection points between the line and the seismic spectrum curve. The largest one is called the highest frequency f _max , and the smallest one is called the minimum frequency f _min . The main frequency of the earthquake f _avg is the average of the two;

Step S04 (obtaining seismically detectable and distinguishable formation thicknesses) includes:

(1) Use the seismic processing process to pick up the final velocity spectrum, and pick up the top, middle and bottom velocities v;

(2) Calculate the seismic detectable stratum thickness h=v/32f _avg respectively according to the calculation formula, obtain the top, middle and bottom detectable stratum thicknesses, and obtain the average value of the three as the stratum detectable thickness of the seismic data;

(3) Calculate the seismically resolvable formation thickness h=v/4f _avg respectively according to the calculation formula, obtain the top, middle and bottom resolvable formation thicknesses, and obtain the average value of the three as the resolvable formation thickness of the seismic data;

Step S05 (field outcrop standard profile measurement data) includes:

(1) Survey the field profiles in sequence according to the numbering sequence of the standard profile survey points;

(2) During the reconnaissance process, while observing the lithology and stratification, record the thickness of each lithologic stratum. The thickness recording range is required to be no larger than the detectable thickness of the earthquake, and the lithology is sampled. The sampling principle is in the detectable thickness of the stratum. To the range of resolvable thickness, at least one sample is required, and the edge of the sample cube is not less than 10cm.

Step S06 (laboratory measurement of rock acoustic velocity and density data) includes:

(1) First of all, according to the data measured in the field, use the conventional method to compile a comprehensive histogram of lithology;

(2) By measuring the density data and P-wave velocity data of the sample, if the experiment cost, the density data of the sample can be measured, and then the P-wave velocity data V _sample of the sample can be reversely calculated. In the laboratory process, the rock sample needs to be dried before Measurement;

V _sample = (ρ _sample × 3.2051) ^4.10257

(3) Add one next to the lithological column in the comprehensive histogram, and record the velocity and density data in this empty channel;

(4) Respectively combine the speed and density data scatter points into a speed data polyline;

This step is also one of the core steps of the present invention, and errors caused by arbitrarily selecting data from other places can be reduced through actual measurement.

Step S07 (obtaining the thickness of the seismic formation) includes:

(1) Group the parts with large velocity difference, and the lithological velocity difference is less than 3% as a group, this grouping is called lithology grouping, and the smallest unit of grouping is called lithology group;

(2) Pick up the thickness of the stratum frame respectively, and use the velocity data processed by the seismic data to calculate the thickness of the frame stratum;

(3) Using the method of seismic facies analysis of Daimao and lithologic groups, combined with the comprehensive histogram of lithology, roughly determine the age of the seismic frame strata;

(4) According to the contact relationship of the seismic stratigraphic frame layer extending to the outcrop point, the method of sedimentary trend comparison is adopted, the thickness h _k of the frame layer is compared with the lithological group h _z measured in the field, and the thickness contrast coefficient K of the lithological group is obtained. ;

(5) Calculate the mean value _ka of the lithological group thickness contrast coefficient;

(6) Use h _z = h _k * _ka to obtain the thickness of the lithologic group as the true stratigraphic thickness of the lithologic group. At this time, the thickness is equivalent to the lithologic assemblage at the comparison point of the seismic section, and the stratum thickness is basically the same;

This step is also one of the core steps of the present invention, which corrects the thickness of the outcrop profile point to the thickness of the seismic profile, thereby reducing the possible deviation of the synthetic seismic trace.

Step S08 (obtaining standard layer reflection coefficient series) includes:

(1) According to the lithological group data, use the formula to obtain the reflection coefficient sequence of the interface between the lithological groups:

In the formula, Ri is the reflection coefficient of the interface formed by lithologic group _i and lithologic group i+1, ρ _i , vi and ρ _{i +1} , vi ₊₁ are the density and acoustic velocity of i and i+1, respectively ;

Step S09 (obtaining seismic wavelets) includes:

(1) Select the rake wavelet and use the average frequency f _avg to calculate the seismic wavelet

where A(t) is the amplitude of the Rake wavelet at the reflection interface, f _avg is the dominant frequency of the earthquake, and t is the time relative to the center point of the convolution in the time window.

Step S10 (calculating synthetic seismic records) includes:

(1) First, according to the speed and thickness data of lithology grouping, time-depth conversion is performed. During the conversion process, the corresponding relationship between time, depth, lithology and geological stratification needs to be recorded at the same time, a basic data comparison reference table is established, and the conversion time is accumulated. The value is compared with the time window value selected by the earthquake, and the maximum value is selected as the calculation time window;

(2) The synthetic seismic record data S(t) is obtained by convolution of the lithological group reflection sequence and seismic wavelet in the corresponding time domain, and accumulated in the calculation time window.

S(t)=R _i (t)*A(t)

where S(t) is the synthetic seismic record data, i is the lithological group number, R _i (t) is the reflection coefficient of the interface formed by the lithological group i and the lithological group i+1, and A(t) is the reflection interface. Rake wavelet amplitude energy, t is the time relative to the center point of the convolution in the time window.

Step S11 (geological interface calibration) includes:

(1) Draw a waveform diagram of the synthetic seismic record data in the coordinate system, which is called a synthetic seismic record, and needs to satisfy: the horizontal is the amplitude value, the vertical is the time, and the time series decreases in turn in the vertical direction;

(2) Adjust the longitudinal time scale of the synthetic seismic recording trace to be consistent with the seismic profile, and adjust the maximum lateral amplitude to be consistent with the seismic profile, superimpose it on the seismic profile, first use the hat method to roughly compare and calibrate the axis with the strongest reflected energy, and then move it up and down Synthesize seismic records, so that the energy relationship between the synthetic seismic records and the actual seismic records is consistent with the longitudinal wave group, and the correlation reaches the maximum. At this time, the seismic records obtained from the field data match the actual profiles;

(3) Using the basic data to compare the corresponding relationship between time, lithology and geological stratification in the reference table, the geological stratification interface is calibrated on the seismic section to realize the final seismic-geological interface calibration.

In the seismic interpretation work of the present invention in a fault depression in the new exploration area, because the deep well of the Cambrian-Ordovician has not been exposed in the southwest, and there is no effective drilling data support, it is impossible to calibrate and distinguish the Ordovician (O) internal strata. , but its northwest uplift has outcrops ①-④ (Fig. 2). Since the seismic section is close to the outcrop and is in the same platform edge slope environment, the depositional environment and stratigraphic structure are similar, so it is possible to Accurately select the seismic-geological layer contrast trace of the seismic profile (Fig. 3). Through the method of the present invention, according to the stratum thickness, lithology and other data measured in the field, the velocity data is obtained from the field profile sampling - the indoor measured section, and combined into a velocity data polyline (Fig. 4), the reflection coefficient of each interface is calculated, and the rake wavelet Convolution, and finally realized the simulation of seismic records in the outcrop geological section in the no-well area. Repeated comparison of the seismic records and the positional reflection characteristics of the seismic profile after translation shows that the correlation between the synthetic seismic records and the seismic geological layers of the seismic profile is the highest, while the two contrasts on the left have low correlations. The positions of the geological layers are relatively accurate. At this time, the main layers can basically be aligned, especially the middle and upper Ordovician strata. Therefore, the geological stratification of the outcrop into Middle Ordovician Dawangou Formation (O ₂ d), Upper Ordovician Sargan Formation (O ₃ s), Upper Ordovician Kanling Formation (O ₃ k), The Upper Ordovician Qilang Formation (O ₃ q) and the Upper Ordovician Yingan Formation (O ₃ y) are accurately calibrated to the seismic profile (line A).

Finally, it should be particularly pointed out that the above preferred examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred examples, those skilled in the art should understand that according to actual geological conditions, Reasonable changes may be made in form and detail without departing from the scope of the invention as defined by the claims.

Claims (10)

1. A method for finely calibrating seismic data geological horizon in a well-free new exploration area is characterized by comprising the following steps:

s01: selecting field standard profile reconnaissance points and sequencing the points;

s02: selecting seismic profile seismic geological horizon contrast channels by means of sedimentary facies belt translation;

s03: obtaining the seismic frequency spectrum and the dominant frequency of the seismic section;

s04: obtaining the thickness of the earthquake detectable stratum and the thickness of the distinguishable stratum;

s05: acquiring field outcrop standard profile measurement data and collecting a rock sample;

s06: measuring rock acoustic velocity and density data in a laboratory;

s07: calculating the thickness of the seismic stratum, and correcting the thickness of the outcrop section point to the thickness of the seismic section;

s08: calculating a reflection coefficient series of the standard layer;

s09: solving seismic wavelets;

s10: calculating a synthetic seismic record;

s11: and (5) calibrating a geological interface.

2. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 1, characterized by comprising the following steps: the step S01 includes:

s011: superposing the plane position of the seismic section survey line and the field outcrop section position on a related basic geological map through a geodetic coordinate system to form a superposed map;

s012: on a superimposed graph, selecting a target stratum dew point on a geological map according to the principle of 'approaching to a measuring line, consistent facies zone and consistent lithology', and selecting a plurality of outcrop points according to the principle by taking a 'group' or a 'section' as a unit, so as to form a field stratum point set corresponding to a seismic section calibration-simulating timing window;

s013: and sequencing the selected outcrop points from new to old, and combining the outcrop points with lines to form a field standard profile survey point with complete stratum.

3. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 2, characterized by comprising the following steps: the step S02 includes:

tracking the homophase axes with strong contrast amplitude energy and good continuity according to the longitudinal and transverse strength change, the frequency, the homophase axis contact relation and the integral seismic reflection characteristics of the homophase axes of the seismic section based on the knowledge of the integral geological characteristics of the newly explored area and the geological research of the outcrop section to obtain a seismic stratum frame interface;

and (2) respectively making the selected outcrop points translate and connect the same phase zone into the seismic section by utilizing a new exploration area sedimentary facies zone division result, wherein the line is intersected with a plane projection line of the seismic section, a middle point of a connection line of a vertical line intersection point of the seismic section is made, the middle point extends to two sides, and 1000 channels with stable seismic stratum frame thickness are selected as seismic contrast channels of the seismic section, so that the consistency of sedimentary sequences of rock layers at the seismic contrast channels and rock layers of a field section is ensured, the rock layer thicknesses of two points are ensured to have a linear relation, and the speed and density parameters of rocks have contrastability.

4. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 3, characterized by comprising the following steps: the step S03 includes:

respectively selecting seismic waves with a time window larger than two periods from the top, the middle and the bottom of the seismic section contrast channel selected from the frame to carry out fast Fourier transform, solving seismic time domain complex spectrum of the top, the middle and the bottom, and if the solved complex spectrum has jumping waves, reselecting and expanding the time window until the wave spectrum is stable to obtain a seismic frequency spectrum;

on the seismic complex spectrum, a horizontal straight line is drawn with the-20 DB signal as a boundary, and the line has two intersections with the seismic spectrum curve: i.e. the highest frequency f _max Minimum frequency f _min From this, the seismic dominant frequency f can be obtained _avg Comprises the following steps:

the step S04 includes:

picking up a final velocity spectrum by using the seismic processing process, and picking up velocities v at the top, the middle and the bottom;

respectively taking the thicknesses of the earthquake detectable strata at the top, the middle and the bottom, and then taking the average value as the thickness of the earthquake data;

respectively calculating the thicknesses of the seismic distinguishable strata at the top, the middle and the bottom, and then taking the average value as the thickness of the seismic distinguishable strata of the seismic data;

the step S05 includes:

sequentially surveying the field profiles according to the sequence;

in the process of surveying, the lithology and layering are observed, meanwhile, the thickness of different lithology strata is measured and recorded, the thickness recording range is not larger than the detectable thickness of the earthquake, and lithology sampling is carried out within the range from the detectable thickness of the strata to the distinguishable thickness of the strata.

5. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 4, characterized by comprising the following steps: the step S06 includes:

compiling a lithology comprehensive histogram by using data measured in the field;

measuring the density data of the sample, and calculating the longitudinal wave velocity data V of the sample by the following formula _{Sample (A)} ：

V _{Sample (A)} ＝(ρ _{Sample (A)} ×3.2051) ^4.10257 ；

Adding a hollow channel beside a lithologic column of the lithologic comprehensive histogram, and recording density data and longitudinal wave velocity data of a sample in the hollow channel;

and respectively combining the density data and the longitudinal wave velocity data scatter point connecting lines into a velocity data broken line.

6. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 5, characterized by comprising the following steps: the step S07 includes:

performing lithology grouping according to the speed difference, wherein the minimum grouping unit is a lithology group;

respectively picking up the thickness of the stratum frame, and calculating the thickness of the stratum frame by using the velocity data processed by the seismic data;

roughly determining the era of the seismic frame stratum by utilizing a capping method and a lithology group seismic facies analysis method and combining a lithology comprehensive histogram;

extending to the outcrop point according to the contact relation of the seismic stratum frame layer, adopting a deposition trend comparison method and utilizing the thickness h of the frame layer _k Lithology group h with field measurement _z Comparing, and solving a lithology group thickness contrast coefficient K;

calculating the average value k of the thickness contrast coefficient of the lithology group _a ；

Using the formula:

h _z ＝h _k *k _a

and (4) calculating the thickness of the lithology group as the thickness of the true stratum of the lithology group, wherein the thickness is equivalent to the lithology combination of the seismic profile comparison point, and the thickness of the stratum is consistent.

7. The method for fine calibration of seismic data geological horizon of a well-free new exploration area as claimed in claim 6, wherein: the step S08 includes:

according to the lithology group data, the reflection coefficient sequence of the interface between the lithology groups is obtained by the following formula:

in the formula, R _i The reflection coefficient, rho, for the interface formed by lithology group i and lithology group i +1 _i 、v _i And ρ _i+1 、v _i+1 Density and sound wave velocity of i and i +1, respectively.

8. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 7, characterized by comprising the following steps: the step S09 includes:

using Rake wavelets and seismic dominant frequency f _avg Computing to obtain seismic wavelets

Wherein A (t) is the amplitude of the Rake wavelet of the reflective interface, f _avg And t is the time of the relative convolution center point in the time window, wherein t is the seismic dominant frequency.

9. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 8, characterized by comprising the following steps: the step S10 includes:

according to the speed and thickness data of lithological grouping, time-depth conversion is carried out, the corresponding relation among time, depth, lithological character and geological stratification needs to be recorded at the same time in the conversion process, a basic data comparison reference table is established, the accumulated value of conversion time is compared with a time window value selected by an earthquake, and the maximum value is selected as a calculation time window;

utilizing convolution of lithology group reflection sequences and seismic wavelets in a corresponding time domain range, accumulating in a calculation time window, and calculating to obtain synthetic seismic record data S (t);

S(t)＝R _i (t)*A(t)

wherein S (t) is synthetic seismic record data, i is lithology group number, R _i (t) is the reflection coefficient of the interface formed by the lithology group i and the lithology group i +1, A (t) is the amplitude energy of the Rake wavelet of the reflection interface, and t is the time of the relative convolution center point in the time window.

10. The method for fine calibration of seismic data geological horizon in a well-free new exploration area according to claim 9, characterized by comprising the following steps: the step S11 includes:

drawing a waveform diagram of the synthetic seismic record data in a coordinate system, wherein the diagram is a synthetic seismic record trace and needs to satisfy the following conditions: the horizontal direction is an amplitude value, the longitudinal direction is time, and the time sequence is sequentially reduced from the longitudinal direction to the upper direction;

adjusting the longitudinal time proportion of the synthetic seismic trace to be consistent with the longitudinal scale of the seismic section, adjusting the maximum value of the transverse amplitude to be consistent with the seismic section, superposing the synthetic seismic trace on the seismic section, roughly comparing and calibrating a maximum reflection energy axis by using a capping method, moving the synthetic seismic trace up and down to ensure that the energy relationship between the synthetic seismic trace and the longitudinal wave group of the actual seismic trace is consistent, and the correlation degree is maximized, wherein the seismic trace obtained by field data is matched with the actual section;

and calibrating the geological stratification interface on the seismic section by using the time, lithology and geological stratification corresponding relation in the basic data comparison reference table, thereby realizing the final seismic geological interface calibration.

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