阅读说明：本技术 一种增强厚煤层下赋煤层成像质量的反褶积应用方法 (Deconvolution application method for enhancing imaging quality of coal seam under thick coal seam ) 是由 解洁清 孟凡彬 郎玉泉 于 2021-02-02 设计创作，主要内容包括：本发明提供一种增强厚煤层下赋煤层成像质量的反褶积应用方法,其特征在于,包括以下步骤：反褶积之前将地震资料的低频信号全部保留；在应用第一种反褶积方法的基础上,对CRP数据动校正拉平后再次串联使用另一种反褶积方法。本发明以改善处理流程中反褶积应用方式来提高厚煤层下赋可采煤层成像质量,进而为矿方提供下赋可采煤层的赋存信息,省去了为得到下赋煤层信息而进行二次地震勘探施工的成本。(The invention provides a deconvolution application method for enhancing imaging quality of a coal seam under a thick coal seam, which is characterized by comprising the following steps of: all low-frequency signals of the seismic data are reserved before deconvolution; on the basis of the first deconvolution method, the CRP data are subjected to dynamic correction flattening and then another deconvolution method is used in series again. The method improves the imaging quality of the lower endowable coal seam of the thick coal seam in a deconvolution application mode in the processing flow, further provides endowment information of the lower endowable coal seam for a mine, and saves the cost of secondary seismic exploration construction for obtaining the information of the lower endowable coal seam.)

1. A deconvolution application method for enhancing imaging quality of a coal seam under a thick coal seam is characterized by comprising the following steps:

all low-frequency signals within 30Hz of the seismic data are reserved before deconvolution;

on the basis of the first deconvolution method, the CRP data are subjected to dynamic correction flattening and then another deconvolution method is used in series again.

2. The deconvolution application method of claim 1, specifically comprising:

the first deconvolution method is surface consistent deconvolution: testing the convolution step value, testing a plurality of step values at equal intervals, setting a main frequency broadening value corresponding to each step value by taking single-shot whole and target layer frequency spectrum analysis as a main monitoring scheme, and comparing to obtain an optimal step value and a corresponding optimal main frequency broadening value;

the other deconvolution method is predictive deconvolution: fully comparing the single prediction with the multi-path prediction, and selecting the coal-forming layer under the thick coal layer as a calculation time window by the convolution time window; fully testing the convolution factors, selecting a plurality of convolution factors at equal intervals for testing, comparing test effects, and finally determining the convolution factor with the best effect;

after the two deconvolutions are used in series, the remaining static correction is carried out again, and the correction time window is the same as the second deconvolution time window.

3. The deconvolution application method of claim 1, wherein the low frequency signal is a low frequency signal having a frequency of 0-30 Hz.

4. The deconvolution application method of claim 2, wherein the step value and the main frequency broadening range vary according to original data, the main frequency broadening range is monitored by testing different step values of the original data and performing spectrum analysis on a single shot, and the step value corresponding to the maximum main frequency broadening range is the optimal step value.

5. A method for applying deconvolution as claimed in claim 2, wherein said determining the best performing convolution factor is based on the following criteria: the test effect is compared by taking the better reinforcement of the amplitudes of the low-frequency end and the high-frequency end of the frequency spectrum of the target layer as a comparison standard, and the optimal convolution factor effect of the multi-channel prediction deconvolution 60 is finally determined.

Technical Field

The invention relates to a seismic data processing method, in particular to a deconvolution application method, which is suitable for a seismic data processing flow required by geological tasks for improving the imaging quality of coal seams under thick coal seams.

Background

The imaging quality of other coal seams which exist under a coal seam with larger thickness is difficult to improve by the existing data processing technology, and the closer the distance, the worse the imaging quality.

Problems and disadvantages: the lower coal seam capable of being mined is influenced by the shielding of the upper coal seam with thick coal seam, the energy of reflected wave is weak, the imaging is poor, the data interpretation is difficult, and the reliable technical support of the lower coal seam capable of being mined is difficult to provide for the mine.

Disclosure of Invention

In order to effectively solve the problems that the imaging quality of the coal seam which can be mined under the thick coal seam is poor and the occurrence form of the coal seam is difficult to explain, the invention provides a deconvolution application method for enhancing the imaging quality of the coal seam which can be mined under the thick coal seam.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a deconvolution application method for enhancing imaging quality of a coal seam under a thick coal seam is characterized by comprising the following steps:

all low-frequency signals of the seismic data are reserved before deconvolution;

based on the application of one deconvolution method, the CRP data is subjected to dynamic correction flattening and then another deconvolution method is used in series again.

The low-frequency signal is a low-frequency signal with the frequency of 0-30 Hz.

The method comprises the following steps:

surface consistent deconvolution: testing the convolution step value, testing a plurality of step values at equal intervals, setting a main frequency broadening value corresponding to each step value by taking single-shot whole and target layer frequency spectrum analysis as a main monitoring scheme, and comparing to obtain an optimal step value and a corresponding optimal main frequency broadening value;

prediction of deconvolution: fully comparing the single prediction with the multi-path prediction, and selecting the coal-forming layer under the thick coal layer as a calculation time window by the convolution time window; fully testing the convolution factors, selecting a plurality of convolution factors at equal intervals for testing, comparing test effects, and finally determining the convolution factor with the best effect;

after the two deconvolutions are used in series, the remaining static correction is carried out again, and the correction time window is the same as the second deconvolution time window.

Compared with the prior art, the invention has the beneficial effects that:

the method improves the imaging quality of the lower endowable coal seam of the thick coal seam in a deconvolution application mode in the processing flow, further provides endowment information of the lower endowable coal seam for a mine, and saves the cost of secondary seismic exploration construction for obtaining the information of the lower endowable coal seam.

Drawings

Fig. 1-5 show the predicted deconvolution of coal seam No. 15 in shanxi area, in the embodiment of the present invention, when the convolution factor is tested, the convolution factor is tested at 20 equal intervals, 20, 40, 60, 80, and 100 are tested, and the test results are shown in fig. 1-5;

fig. 6 is a schematic diagram illustrating the gradual frequency band widening effect of the spectral analysis after two deconvolution of coal seam No. 15 in shanxi area in the embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating the effect of wavelet compression effect gradual optimization after two deconvolution of coal seam No. 15 in Shanxi;

FIG. 8 is a flowchart of a method for improving the imaging quality of a coal seam No. 15 under a thick coal seam in a certain area in Shanxi in accordance with an embodiment of the present invention;

FIG. 9 is a schematic view of an imaging improvement sequence of a thick coal seam lower coal seam after two deconvolutions of a coal seam No. 15 in a certain area in Shanxi region are used in series and then subjected to a remaining static correction in the embodiment of the present invention;

fig. 10 is a diagram illustrating the effect of performing twice deconvolution treatment on an 8-coal seam 50m below the number 7 coal seam in a certain area in north of huai province.

Detailed Description

In order to make the technical means, characteristics and effects of the invention easy to understand, the invention is further described below with reference to the specific embodiments.

A certain Shanxi area is taken as a test area, and the following technical scheme is provided:

a deconvolution application method for enhancing imaging quality of a coalbed under a thick coal seam comprises the following steps:

all low-frequency signals within 30Hz of the seismic data are reserved before deconvolution;

based on the application of one deconvolution method, the CRP data is subjected to dynamic correction flattening and then another deconvolution method is used in series again.

The method requires to keep low-frequency information, namely, the low-frequency information is not filtered when a filtering gear is set, and a low-frequency signal of 0-30Hz is kept.

The specific experiment is as follows:

the thick coal layer which can be mined in the region mainly comprises No. 3 coal and No. 9 coal, and the thickness of the coal layer is more than 10 m. The main target layer of the geological mission is No. 15 coal, and is about 80m below No. 9 coal. Because the thickness of the upper coal No. 3 and 9 is large, the shielding effect on the coal No. 15 is strong, and the coal No. 15 cannot form a good-continuity in-phase axis, so that the occurrence state of the coal No. 15 cannot be explained. Based on this, the method test was performed.

The idea of the test method is as follows: on the basis that low-frequency signals are fully reserved in original data, earth surface consistency deconvolution processing is carried out after pre-stack noise attenuation, then dynamic correction leveling in the CRP direction is carried out on the data, further the speed is optimized, iteration of residual static correction and the speed is carried out, and on the basis that the residual static correction value is fully optimized, deconvolution is predicted in series, so that the method greatly improves the imaging quality of the coal-forming bed under the thick coal bed (see an application flow chart of a method in fig. 8). The concrete measures are as follows:

first deconvolution, namely the surface consistent deconvolution: the convolution step value is mainly tested, the step values are tested 4, 8, 12, 16 and 20 at equal intervals 4, and single shot whole and target layer spectrum analysis is used as a main monitoring scheme. The test results are: the step 4 of main frequency expansion is widened to 15-55Hz, the step value 8 of main frequency is widened to 12-65 Hz, the step value 12 of main frequency is widened to 8-80Hz, and the step values 16 and 20 of main frequency are widened to the effect of synchronous length value 12. By comparison, the step size value 12 is optimal for this zone test, with the corresponding main frequency broadening from 25-45Hz to 8-80Hz, see FIGS. 6 a-b. It should be noted that the step value and the main frequency widening range vary according to the original data, and the main frequency widening range can be monitored only by testing different step values on the original data and then performing spectrum analysis on a single gun, and the maximum main frequency widening range is the best.

Because the original data is influenced by a plurality of random factors such as surface construction conditions, environment, weather, excitation factors and the like, and the generated noise is different according to the data, the noise attenuation method needs to be applied according to the symptoms, and different noise has different targeted attenuation methods. The following types of noise are common in coal field exploration: low frequency surface waves, sound waves, linear interference, industrial interference, outlier interference, multiples interference, ground roll interference, and the like. Various mature processing software applied in the market has a better processing method for the noise. The optimal principle of denoising is to remove the interference noise and simultaneously keep the effective reflection signal, namely, the harm to the effective reflection signal is the lowest. The present embodiment mainly aims at the deconvolution application method, which belongs to two major modules in the seismic data processing flow with the noise attenuation, and the order of use is after the deconvolution is subjected to noise attenuation.

The deconvolution of the second series is the predicted deconvolution: fully comparing single prediction with multi-path prediction, selecting a coal layer under a thick coal layer as a calculation time window by using a convolution time window, and selecting 10ms under a No. 9 coal layer of the thick coal layer as an initial calculation time window in the area; and the convolution factors are fully tested, the convolution factors are tested at equal intervals of 20, and the test results of the test results in the area of 20, 40, 60, 80 and 100 are shown in figures 1 to 5. The test effect is compared by taking the better reinforcement of the amplitudes of the low-frequency end and the high-frequency end of the frequency spectrum of the target layer as a comparison standard, and the optimal convolution factor effect of the multi-channel prediction deconvolution 60 is finally determined. After the second deconvolution of the spectrum analysis, the amplitudes of the low-frequency end and the high-frequency end of the target layer spectrum are better enhanced, as shown in fig. 6 b to c.

Through the optimization and combined use of the two deconvolutions, the wavelet compression effect is gradually optimized, and the figure 7 shows.

After the two times of deconvolution are used in series, the remaining static correction is carried out again, the correction time window is the same as the second time of deconvolution time window (starting 10ms below the thick coal seam), and after the processing of the method, the imaging quality of the coal seam under the thick coal seam is greatly improved, and a better basis is provided for the occurrence form explanation of the coal seam as shown in figure 9. The residual static correction is: calculating the time window from 10ms below the coal seam with the thickness up to about 200ms below the target layer; calculating frequency and keeping low frequency, and setting the range from 0Hz to 100 Hz; and calculating the coal seam fluctuation condition of the dip angle selection reference processing block.

The key points in the application of the method are as follows:

after the noise of the single cannon is attenuated, the first anti-pleating machine processing is carried out, and all low-frequency components within 30Hz are reserved;

before the second series deconvolution, the gradual iterative optimization of residual static correction and speed analysis is needed, and the iteration times are more than or equal to three times; the combined use of deconvolution with velocity analysis, the remaining static correction iterations, is shown in the process flow of FIG. 8.

And after the second time of serial deconvolution, performing a residual static correction again, wherein a correction time window is the same as a calculation time window of the second time of deconvolution, namely, 10ms below the thick coal seam is taken as the starting point, so that the data imaging quality is further improved.

The method has general applicability in other areas, and has better application effect by performing targeted treatment on an 8-coal seam 50m (closer to) below No. 7 coal in a thick coal seam in a certain area in Huaibei, as shown in FIG. 10.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.