CN104199101A - Quantitative analysis method of seismic wave propagation complexity under complex terrain condition - Google Patents

Abstract

The invention relates to a quantitative analysis method of seismic wave propagation complexity under a complex terrain condition. The method includes: importing complex terrain data which is space coordinates, containing elevation, of wave detection points on an earthquake detecting line; using the space coordinate information to calculate the terrain dip angle heterogeneous spectrum of the complex terrain; using the angular spectrum function g(theta) of a Fourier finite difference method and the dip angle heterogeneous spectrum q(theta) of the complex terrain to calculate the seismic wave propagation efficiency under the complex terrain condition; using the seismic wave propagation efficiency under the complex terrain condition to calculate the seismic wave propagation complexity under the complex terrain condition. By the method, quantitative evaluation of the seismic wave propagation efficiency caused by the complex terrain condition is achieved, influence of different complex terrains on seismic wave propagation and the quality of seismic data received by the complex terrains are quantitatively evaluated, the seismic exploration effect of the complex terrains is predicted accurately, and blindness of seismic exploration is avoided.

Description

Seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY

Technical field

The present invention relates to the seismic prospecting assay technology in a kind of oil seismic exploration assay field, particularly relate to seismic wave propagation complicacy quantitative analysis method under a kind of MODEL OVER COMPLEX TOPOGRAPHY.

Background technology

Fast continual development along with China's economy, the ratio of crude oil in China import volume and Amount of Consumption of Crude Oil becomes more and more higher, and can predict, further sustainable development along with Chinese national economy, externally interdependency also will further improve, make a general survey of the course of domestic and international oil-gas exploration and development, along with the exploitation of plains region shallow-layer simple structure hydrocarbon-bearing pool totally, for the seismic prospecting under complex near surface conditions, find hydrocarbon-bearing pool and become more and more important, in complicated earth surface seismic prospecting, complicated earth's surface topographic condition particularly, especially in complicated area, mountain region, will directly to data acquisition quality, cause adverse effect, in practice of construction, base area seismic wave is taken measures pointedly at the propagating characteristic in complex-terrain area, select good exciting, condition of acceptance, take effective working measure, optimize acquisition parameter, obtain optimal acquisition effect, the petroleum prospecting success ratio improving under MODEL OVER COMPLEX TOPOGRAPHY is had to important meaning.

In the seismic prospecting practice of Complex Mountain landform, people are the effect of base area seismic wave propagation usually, from obtaining seismologic record, qualitatively judge the complicacy impact of complex-terrain on seismic prospecting, quantitative test complex-terrain changes complicacy in Seismological Significance and has important theory significance and using value widely, utilize seismic wave propagation complicacy quantitative analysis tech under complex-terrain can accurately distinguish the seismic wave propagation complicacy of different regions and dissimilar complex-terrain, for seismic prospecting data collecting conceptual design, geological data treatment scheme is determined and seismic interpretation fail-safe analysis provides foundation.The quality of the seismic data that particularly can quantitative evaluation different complex-terrains receive the impact of seismic wave propagation and complex-terrain, realizes the effect of predicting comparatively exactly complex structure seismic prospecting, avoids the blindness of seismic prospecting.

In general, change of pitch angle heterogeneous body that can calculation of complex landform by statistical study is composed, from the angle of geology, realize complex-terrain at the quantitative expression aspect landform change of pitch angle, yet, this geologic complex-terrain quantization signifying only has geological Significance, survey irrelevant with seismic wave propagation, on the other hand, the propagation characteristic of seismic event in complex-terrain can be described by wave equation propagation operator, seismic spread operator or seismic imaging operator can carry out by the dispersion equation of its parsing its precision of quantitative test, it is propagation operator angular spectrum function, with this, its imaging precision is described with the Changing Pattern of slowness and propagation angle, by the heterogeneous body spectrum that the landform angle of complex-terrain is changed, join with the angular spectrum functional dependence of seismic imaging operator, can define a kind of about complex-terrain the complexity coefficient with respect to seismic spread operator, the qualitative assessment of realization to the seismic investigation complexity of complex-terrain.

Under at present conventional Analysis of Complex topographic condition, on the method for estimation of seismic wave propagation impact, be mainly to utilize field test to carry out, this method exists cost height and poor the determining of universality, test the impact on seismic wave propagation of Analysis of Complex landform that regional field collection test can not be independent, can not realize the Complexity Assessment analysis with the test inconsistent area of regional complex-terrain feature.

Summary of the invention

In view of this, fundamental purpose of the present invention is to provide seismic wave propagation complicacy quantitative analysis method under a kind of MODEL OVER COMPLEX TOPOGRAPHY, overcoming in existing field collection test analytical approach cannot the defect of qualitative assessment complex-terrain on seismic wave propagation impact, pass through the technical program, Quantitative Analysis to the seismic wave propagation complicacy under MODEL OVER COMPLEX TOPOGRAPHY, obtain a concrete numerical value as the foundation of evaluating the seismic wave propagation complicacy under seismic line MODEL OVER COMPLEX TOPOGRAPHY, the impact of quantitative test complex-terrain on seismic wave propagation, utilize the present invention can realize for certain complex-terrain situation, the complicacy that the earthquake wave-wave of the different surveys line of quantitative contrast is propagated, evaluate quality and the impact of complex-terrain on seismic data that survey line distributes, thereby select to be more suitable in the acquisition scheme of this complex-terrain and the scheme of the geological data static corrections processing that is more suitable for gathering in this complex-terrain.

In order to achieve the above object, technical scheme of the present invention is achieved in that

A seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY, carry out according to the following steps:

1) import complex-terrain data, complex-terrain data be on seismic line geophone station containing elevation volume coordinate;

2) utilize complex-terrain containing elevation volume coordinate information, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain;

3) the angular spectrum function g (θ) that utilizes Fourier's finite difference method and step 2) the landform inclination angle heterogeneous body spectrum q (θ) of this complex-terrain of calculating, the seismic wave propagation efficiency under calculation of complex topographic condition;

4) utilize step 3) MODEL OVER COMPLEX TOPOGRAPHY under seismic wave propagation efficiency, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition;

Above-mentioned steps 2) in, for any point position (x on landform interface location _i, z _i) inclination angle [theta] (x _i, z _i) can be obtained by formula (1) below:

θ(x _i,z _i)＝arctan(z _i+1-z _i)/(x _i+1-x _i) (1)

Through calculating, just utilize the bed boundary of subsurface geological structure and the tilt profiles θ (x, z) that position of fault distribution obtains the each point of subsurface geological structure;

Suppose that, according to for interval delta θ, angle being carried out to probability statistics, the number that angle value is θ is Δ M, adds up to M, the probability density that whole piece angle measurement upper angle value is θ can be expressed as:

$q\left(\mathrm{\θ}\right)=\frac{\mathrm{\ΔM}}{\mathrm{M\Δ\θ}},---\left(2\right)$

This curve of formula (2) is called frequency curve or frequency curve, because the summation of frequency is 1, therefore the area on transverse axis is 1 under this curve, that is:

$q\left(\mathrm{\θ}\right)=\underset{\mathrm{\Δ\θ}\→0}{\lim }\frac{\mathrm{\ΔM}}{\mathrm{M\Δ\θ}}=\frac{1}{M}\frac{\mathrm{dM}}{\mathrm{d\θ}},$ And ${\∫}_0^{1}q\left(\mathrm{\θ}\right)\mathrm{d\θ}=1.---\left(3\right)$

Thereby utilize the volume coordinate information of complex-terrain, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain.

Above-mentioned steps 3) in, the higher Fourier's finite difference method (FFD) of precision mixing with Fourier conversion for finite difference (FD), its dispersion relation is that the reasonable operator approaching is expressed:

${\stackrel{\‾}{k}}_z=\sqrt{1-{\stackrel{\‾}{k}}_x^2}+n-1+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\frac{a_j\left(n\right){\stackrel{\‾}{k}}_x^2}{1+b_j\left(n\right){\stackrel{\‾}{k}}_x^2},---\left(4\right)$

In formula, k ₀, k _x, k _zbe respectively background wave number, x direction wave number, z direction wave number, n is refractive index, coefficient a _jand b (n) _j(n) be refractive index function, with lateral speed change, change;

The angular spectrum function of a seismic spread operator can be expressed as δ n=g (θ), the i.e. function using the variation δ n=1-n of refractive index as propagation angle theta, the angular spectrum function g (θ) of Fourier's finite difference method (FFD), thus the seismic spread efficiency of definition is:

$\mathrm{\η}={\∫}_0^{1}g\left(\mathrm{\θ}\right)q\left(\mathrm{\θ}\right)\mathrm{d\θ}---\left(5\right)$

Utilize formula 5) obtain the angular spectrum function g (θ) of q (θ) and Fourier's finite difference method (FFD), just can be by calculating the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY.

Above-mentioned steps 4) in, utilize the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition, in formula (5), η is the propagation efficiency of seismic wave propagation operator to landform change of pitch angle, and the seismic prospecting complexity coefficient that the seismic wave propagation complexity of the complex-terrain corresponding with seismic spread efficiency changes can be expressed as:

In formula (6), represented that the seismic wave propagation complexity under MODEL OVER COMPLEX TOPOGRAPHY changes.

Adopt the beneficial effect after technique scheme to be: seismic wave propagation complicacy quantitative analysis method under a kind of MODEL OVER COMPLEX TOPOGRAPHY, pass through the technical program, realized the qualitative assessment to the caused seismic wave propagation complicacy of complex-terrain, the quality of the seismic data that the different complex-terrains of quantitative evaluation receive the impact of seismic wave propagation and complex-terrain, realize the effect of the seismic prospecting of predicting comparatively exactly complex-terrain, avoid the blindness of seismic prospecting.

Accompanying drawing explanation

Fig. 1 is technical side's block diagram of the present invention;

Fig. 2 is landform inclination angle heterogeneous body spectrum q (θ) schematic diagram of complex-terrain in the present invention;

Fig. 3 is angular spectrum function g (θ) schematic diagram of Fourier's finite difference method (FFD) in the present invention.

Fig. 4 is earthquake work area schematic diagram.

Fig. 5 is earthquake side line schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail.

As shown in Figure 1, seismic wave propagation complicacy quantitative analysis method under the MODEL OVER COMPLEX TOPOGRAPHY the present invention relates to, carry out according to the following steps:

1) import complex-terrain data, complex-terrain data be on seismic line geophone station containing elevation volume coordinate;

2) utilize complex-terrain containing elevation volume coordinate information, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain;

3) the angular spectrum function g (θ) that utilizes Fourier's finite difference method and step 2) the landform inclination angle heterogeneous body spectrum q (θ) of this complex-terrain of calculating, the seismic wave propagation efficiency under calculation of complex topographic condition;

4) utilize step 3) MODEL OVER COMPLEX TOPOGRAPHY under seismic wave propagation efficiency, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition;

Above-mentioned steps 2) in, for any point position (x on landform interface location _i, z _i) inclination angle [theta] (x _i, z _i), can be obtained by formula (1) below:

θ(x _i,z _i)＝arctan(z _i+1-z _i)/(x _i+1-x _i) (1)

Through calculating, just utilize the bed boundary of subsurface geological structure and the tilt profiles θ (x, z) that position of fault distribution obtains the each point of subsurface geological structure;

Suppose that, according to for interval delta θ, angle being carried out to probability statistics, the number that angle value is θ is Δ M, adds up to M, the probability density that whole piece angle measurement upper angle value is θ can be expressed as:

$q\left(\mathrm{\θ}\right)=\frac{\mathrm{\ΔM}}{\mathrm{M\Δ\θ}},---\left(2\right)$

As shown in Figure 2, the frequency table of this distribution is histogram, if observing number of cases increases gradually, group section is constantly minute thin, and the line on histogram top will form gradually a peak and be positioned at central authorities (place, mean place), not with the crossing smooth curve figure of transverse axis, this curve of formula (2) is called frequency curve or frequency curve, because the summation of frequency is 1, therefore the area on transverse axis is 1 under this curve, that is:

$q\left(\mathrm{\θ}\right)=\underset{\mathrm{\Δ\θ}\→0}{\lim }\frac{\mathrm{\ΔM}}{\mathrm{M\Δ\θ}}=\frac{1}{M}\frac{\mathrm{dM}}{\mathrm{d\θ}},$ And ${\∫}_0^{1}q\left(\mathrm{\θ}\right)\mathrm{d\θ}=1.---\left(3\right)$

Thereby utilize the volume coordinate information of complex-terrain, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain.

Above-mentioned steps 3) in, the higher Fourier's finite difference method (FFD) of precision mixing with Fourier conversion for finite difference (FD), its dispersion relation is that the reasonable operator approaching is expressed:

${\stackrel{\‾}{k}}_z=\sqrt{1-{\stackrel{\‾}{k}}_x^2}+n-1+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\frac{a_j\left(n\right){\stackrel{\‾}{k}}_x^2}{1+b_j\left(n\right){\stackrel{\‾}{k}}_x^2},---\left(4\right)$

In formula, k ₀, k _x, k _zbe respectively background wave number, x direction wave number, z direction wave number, n is refractive index, coefficient a _jand b (n) _j(n) be refractive index function, with lateral speed change, change;

The angular spectrum function of a seismic spread operator can be expressed as δ n=g (θ), the i.e. function using the variation δ n=1-n of refractive index as propagation angle theta, the angular spectrum function g (θ) of Fourier's finite difference method (FFD), thus the seismic spread efficiency of definition is:

$\mathrm{\η}={\∫}_0^{1}g\left(\mathrm{\θ}\right)q\left(\mathrm{\θ}\right)\mathrm{d\θ}---\left(5\right)$

Utilize formula 5) obtain the angular spectrum function g (θ) of q (θ) and Fourier's finite difference method (FFD), just can be by calculating the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY.

Above-mentioned steps 4) in, utilize the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition, in formula (5), η is the propagation efficiency of seismic wave propagation operator to landform change of pitch angle, and the seismic prospecting complexity coefficient that the seismic wave propagation complexity of the complex-terrain corresponding with seismic spread efficiency changes can be expressed as:

In formula (6), represented that the seismic wave propagation complexity under MODEL OVER COMPLEX TOPOGRAPHY changes, by the angle from seismic wave propagation, realized the qualitative assessment to the caused seismic wave propagation complicacy of complex-terrain, the quality of the seismic data that the different complex-terrains of quantitative evaluation receive the impact of seismic wave propagation and complex-terrain, thereby realize the effect of predicting comparatively exactly complex-terrain seismic prospecting, avoid the blindness of seismic prospecting.

Technical scheme of the present invention in actual applications, as shown in Figure 4, in the earthquake-capturing work area for Complex Mountain, the terrain feature at the place of every seismic line k is different, seismoreceiver is distributed on the complex-terrain of fluctuating, as shown in Figure 5, for any seismic line k wherein, the complexity of seismic wave propagation is relevant with landform inclination angle [theta], by calculating the landform inclination angle [theta] of the upper every bit i of seismic line k, can obtain the angular spectrum distribution function of landform inclination angle [theta], then by the computing formula of the complexity of seismic wave propagation, just can obtain the seismic wave propagation complexity of every seismic line k.

In the present invention, the application of result of calculation is exactly to utilize on the different complex-terrains of the seismic wave propagation complexity quantitative evaluation of calculating, the complexity of the upper seismic wave propagation of different earthquake survey line k, thus realize the effect of predicting exactly the seismic prospecting of complex-terrain in the mode of quantitative test.

The above, be only better possible embodiments of the present invention, not in order to limit scope of the present invention.

Claims (4)

1. a seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY, is characterized in that, carries out according to the following steps:

1) import complex-terrain data, complex-terrain data be on seismic line geophone station containing elevation volume coordinate;

2) utilize complex-terrain containing elevation volume coordinate information, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain;

3) the angular spectrum function g (θ) that utilizes Fourier's finite difference method and step 2) the landform inclination angle heterogeneous body spectrum q (θ) of this complex-terrain of calculating, the seismic wave propagation efficiency under calculation of complex topographic condition;

4) utilize step 3) MODEL OVER COMPLEX TOPOGRAPHY under seismic wave propagation efficiency, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition.

2. seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY according to claim 1, is characterized in that the step 2 of described claim 1) in, for any point position (x on landform interface location _i, z _i) inclination angle [theta] (x _i, z _i) can be obtained by formula (1) below:

θ(x _i,z _i)＝arctan(z _i+1-z _i)/(x _i+1-x _i) (1)

Through calculating, just utilize the bed boundary of subsurface geological structure and the tilt profiles θ (x, z) that position of fault distribution obtains the each point of subsurface geological structure;

Suppose that, according to for interval delta θ, angle being carried out to probability statistics, the number that angle value is θ is Δ M, adds up to M, the probability density that whole piece angle measurement upper angle value is θ can be expressed as:

This curve of formula (2) is called frequency curve or frequency curve, because the summation of frequency is 1, therefore the area on transverse axis is 1 under this curve, that is:

and

Thereby utilize the volume coordinate information of complex-terrain, calculate the landform inclination angle heterogeneous body spectrum of this complex-terrain.

3. seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY according to claim 1, it is characterized in that, described claim 1 step 3) in, the higher Fourier's finite difference method (FFD) of precision mixing with Fourier conversion for finite difference (FD), its dispersion relation is that the reasonable operator approaching is expressed:

In formula, k ₀, k _x, k _zbe respectively background wave number, x direction wave number, z direction wave number, n is refractive index, coefficient a _jand b (n) _j(n) be refractive index function, with lateral speed change, change;

The angular spectrum function of a seismic spread operator can be expressed as δ n=g (θ), the i.e. function using the variation δ n=1-n of refractive index as propagation angle theta, the angular spectrum function g (θ) of Fourier's finite difference method (FFD), thus the seismic spread efficiency of definition is:

Utilize formula 5) obtain the angular spectrum function g (θ) of q (θ) and Fourier's finite difference method (FFD), just can be by calculating the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY.

4. seismic wave propagation complicacy quantitative analysis method under MODEL OVER COMPLEX TOPOGRAPHY according to claim 1, it is characterized in that, described claim 1 step 4) in, utilize the seismic wave propagation efficiency under MODEL OVER COMPLEX TOPOGRAPHY, carry out seismic wave propagation Complexity Coefficient under calculation of complex topographic condition, in formula (5), η is the propagation efficiency of seismic wave propagation operator to landform change of pitch angle, and the seismic prospecting complexity coefficient that the seismic wave propagation complexity of the complex-terrain corresponding with seismic spread efficiency changes can be expressed as:

In formula (6), represented that the seismic wave propagation complexity under MODEL OVER COMPLEX TOPOGRAPHY changes.