CN105510964A - Seismic recognition method of low-order strike-slip faults in complex structural areas - Google Patents

Abstract

The invention belongs to the petroleum exploration field and relates to a seismic recognition method of low-order strike-slip faults in complex structural areas. The seismic recognition method of the low-order strike-slip faults in the complex structural areas includes the following steps that: post-stack seismic data quality is analyzed; processing is carried out to obtain an advantageous frequency division phase band; processing is carried out to obtain Sobel operators in main directions; processing is carried out to Sobel operators in arbitrary directions; a multi-direction lower-order strike-slip fault system is extracted; and the reliability of the low-order strike-slip faults is verified. The method of the invention is suitable for seismic recognition and verification reliability of lower-order strike slip faults in any complex structural belts and can directly reflect the combination modes and spatial locations of lower-order strike-slip faults on a plane; and the method is an effective measure to determine low-order hidden faults in low signal-to-noise ratio and low-frequency seismic data areas and can provide an important basis for re-understanding of hidden fault oil control rules, reservation and production improvement, development plan deployment and adjustment in complex structural oil and gas fields or fault block oil and gas fields.

Description

The seismic identification of the rudimentary sequence strike-slip fault in complex structural area

Technical field

The invention belongs to petroleum exploration field, particularly, relate to the seismic identification of the rudimentary sequence strike-slip fault in a kind of complex structural area.

Background technology

Strike-slip fault in petroliferous basin not only Forming Mechanism is various, widely distributed, and in rich accumulation of oil and gas, play very important effect; Rudimentary sequence strike-slip fault is as the disguised adjusting faults pattern of one, being everlasting in subrange causes stress distribution uneven, cause producing a series of gap and microfissure, greatly improve the perviousness of reservoir, significantly improve the production capacity of low hole reservoir, but be limited to complex structural area seismic data quality and rudimentary sequence strike-slip fault often shows as a kind of Transfer tectonics type, there is feature that is disguised and multi-direction growth, thus it effectively identifies the important topic become in progressive exploratioon and development research.

At present in oil exploration and development fields, quite ripe and reliable to the seismic interpretation method and technology of conventional fracture system, but to low order fault especially to the identification still aobvious difficulty of the deep layer low order fault of seismic data quality difference.The investigative technique of current this respect mainly contains dropping cut slice technology, multiple dimensioned coherent technique, variance cube technology, dip scanning technology, chaos attribute technology, ant group track training technology and faultage image enhancing technology etc., but dropping cut slice technology can only be used for identifying fairly large, combine better simply tomography, identification for low order fault only plays reference role, multiple dimensioned coherent technique and variance cube technology are emphasizing uncorrelated exception, outstanding uncontinuity, by Coherent processing and explanation, can pick out and tomography, the Related Geological Phenomenas such as crack, as higher in seismic data signal to noise ratio (S/N ratio), then there is certain effect to low order fault identification.The layer position of dip and azimuth attribute analysis technology General Requirements input is complete automatic tracing or interpolation, requires higher to seismic data quality, therefore, for low order fault then to judge.The chaos attribute of the chaos attribute that chaos attribute technology is then determined by seismic channel data covariance matrix eigenwert and tomography is portrayed, better for the outstanding tomography effect containing shatter belt.Like the ant group track training technology of fault surface, adopt poststack two and three dimensions longitudinal wave earthquake data, finally obtain a low noise by noise reduction, calculating differential body and inclination angle body, there is the data volume of clear splitting traces, and there is certain trend pass filtering function, often fuzzy composition is weeded out, therefore cause the loss of certain effective constituent and the non-continuous event of space splitting traces, and earthquake data demand is wanted high relatively.Faultage image strengthens technology and mainly contains Adaptive directionalfilter technology, border keeps filtering technique and edge detecting technology, the most frequently used edge enhancing technique utilizes structure to reflect uncontinuity feature and particular lithologic body profile to the differentiating operator of pixel grey scale Spline smoothing sensitivity, as Robert operator, Sobel operator, Prewitt operator, Laplacian operator, Canny operator etc., compared with other operator, Sobel operator has done weighting for the impact of pixel location, edge fog degree can be reduced, therefore better effects if, and when not considering noise, the marginal information error obtained is no more than 7 degree, but the edge extracted is thicker, need to carry out thinning processing, and the selection of regulatory thresholds directly affects the result of detection, also fail to carry out specific aim process for the tomography of different directions.

Therefore, complicated in structural setting, seismic data quality is low, walk sliding turn-off is not obvious, tomography extended distance is short prerequisite under, rudimentary sequence strike-slip fault is disguised by force, identification difficulty is large, need to combine advanced seismic processing technique and mathematical algorithm, Sobel operator is improved, portray result to protrude for different directions tomography, have not yet to see relevant report.

Summary of the invention

For overcoming the defect that prior art exists, the invention provides the seismic identification of the rudimentary sequence strike-slip fault in a kind of complex structural area, obtain rudimentary sequence strike-slip fault based on the Sobel algorithm improved in conjunction with semi-automatic tracer technique in structural complex, and then adopt meticulous Strata Comparison and dipmeter logging combination technique checking tomography reliability.

For achieving the above object, the present invention adopts following proposal:

The seismic identification of the rudimentary sequence strike-slip fault in complex structural area, step is as follows:

Step 1: analyze poststack seismic data quality

Step 2: process acquisition advantage frequency-shared phase band

Step 3: process obtains principal direction Sobel operator

Step 4: process obtains any direction Sobel operator

Step 5: extract multi-direction rudimentary sequence strike-slip fault system

Step 6: verify rudimentary sequence strike-slip fault reliability.

Relative to prior art, the present invention has following beneficial effect: the rudimentary sequence strike-slip fault seismic recognition and the reliability demonstration that are suitable for any complex structure band, has systematization, precision is high, counting yield is high advantage; In the fault recognizing of Tectonic superimposition of many phases recombination region, contain the seismic data volume extracting Advantage height frequency band and different strike fault can be reflected, can the array mode of rudimentary sequence strike-slip fault and locus on reflection planes directly perceived, it is the effective means determining low signal-to-noise ratio, the hidden tomography of the rudimentary sequence in low-frequency acoustic information data area, be ensure to re-recognize fault controlling oil rule hidden in complex structure oil gas field or fault-blcok oil-gas field, increasing the storage produced, development plan disposes and the important evidence of adjustment, is obviously superior to the effect that conventional algorithm carries out portraying at tomography edge.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of the seismic identification of the rudimentary sequence strike-slip fault in complex structural area;

Fig. 2 is that the Sobel operator Difference Gradient improved calculates four principal direction schematic diagram (EW to, SN to, NW-SE to, NE-SW to);

Fig. 3 calculates effect contrast figure based on the Sobel operator filtering improved and Laplace operator;

Fig. 4 is the four direction filtering level tomographic systems figure obtained based on ant tracing algorithm.

Embodiment

As shown in Figure 1, the seismic identification of the rudimentary sequence strike-slip fault in complex structural area, step is as follows:

Step 1: analyze poststack seismic data quality, concrete grammar is as follows:

Collect existing poststack time domain or Depth Domain seismic data, load existing interpre(ta)tive system, determine and follow the trail of objective interval reflection interval at the bottom of three-dimensional top of Water demand, obtain object short time-window data volume, carry out short window discrete Fourier transform or Maximum Entropy Spectral Estimation, generated frequency territory phase spectrum data volume;

Step 2: process acquisition advantage frequency-shared phase band, concrete grammar is as follows:

On seismic interpretation Visualization Platform, observe different frequency section and delayed phase distribution, choose clear, the obvious phase slices of primary and secondary fault complex of principal fault display as dominant frequency phase slices, carry out the statistical study of primary and secondary tomographic systems parameter, rule of thumb, that determines strike-slip fault or lateral adjustments tomography moves towards interval or scope, extracts the earthquake advantage phase place frequency band obtaining and can reflect below 25m turn-off, and carries out normal state smoothing processing and eliminate Gibbs phenomenon;

Step 3: process obtains principal direction Sobel (Sobel) operator, comprises following three steps:

(1), the operator that the dominant frequency band seismic data giving prominence to low-grade fault after process carries out based on comprising two group of 3 × 3 matrix is calculated, planar convolution computing is done again with often some seismic amplitude data, draw horizontal and longitudinal data difference approximate value, represent raw data with A, Δ _xg (x, y) and Δ _yg (x, y) represents the data variation value detected through transverse direction and longitudinal edge respectively, and computing formula is as follows:

$\begin{array}{c}{\mathrm{\Δ}}_{x}G(x,Y)=\[G(x-1,y+1)+2G(x,y+1)+G(x+1,y+1)\]-\[G(x-1,y-1)+2G(x,y-1)+G(x+1,y-1)\]\\ =\left[\begin{array}{ccc}-1& 0& 1\\ -2& 0& 2\\ -1& 0& 1\end{array}\right]\·A\end{array}$

$\begin{array}{c}{\mathrm{\Δ}}_{y}G(x,Y)=\[G(x-1,y-1)+2G(x-1,y)+G(x-1,y+1)\]-\[G(x+1,y-1)+2G(x+1,y)+G(x+1,y+1)\]\\ =\left[\begin{array}{ccc}-1& -2& -1\\ 0& 0& 0\\ 1& 2& 1\end{array}\right]\·A\end{array}$

Its convolution mask operator is as follows:

$T_x=\left[\begin{array}{ccc}-1& 0& 1\\ -2& 0& 2\\ -1& 0& 1\end{array}\right],T_y=\left[\begin{array}{ccc}-1& -2& -1\\ 0& 0& 0\\ 1& 2& 1\end{array}\right]$

(2), carry out squelch process, based on transverse direction, longitudinal edge operator, superposition obtains the operator template T of the size 5 × 5 in transverse direction, longitudinal direction, NE45 °, NE315 ° four principal directions _x, T _y, T ₄₅, T ₃₁₅, and root side is opened to each matrix operator obtain matrix isotropy Sobel operator, the weight location of each template is by the distance G (x of place-centric, y) and the direction of position determined, equidistant points has identical weight, to spiral amplitude data with four principal direction operator templates, total Grad G obtains by increasing by two inclination matrixes, obtains data exception edge by dual threshold algorithm:

$T_x=\left[\begin{array}{ccccc}2& 3& 0& -3& -2\\ 3& 4& 0& -4& -3\\ 6& 6& 0& -6& -6\\ 3& 4& 0& -4& -3\\ 2& 3& 0& -3& -2\end{array}\right],T_y=\left[\begin{array}{ccccc}2& 3& 6& 3& 2\\ 3& 4& 6& 4& 3\\ 0& 0& 0& 0& 0\\ -3& -4& -6& -4& -3\\ -2& -3& -6& -3& -2\end{array}\right]$

$T_{45}=\left[\begin{array}{ccccc}0& -2& -3& -2& -6\\ 2& 0& -4& -6& -2\\ 3& 4& 0& -4& -3\\ 2& 6& 4& 0& -2\\ 6& 2& 3& 2& 0\end{array}\right],T_{135}=\left[\begin{array}{ccccc}-6& -2& -3& -2& 0\\ -2& -6& -4& 0& 2\\ -3& -4& 0& 4& 2\\ -2& 0& 4& 6& 2\\ 0& 2& 3& 2& 6\end{array}\right]$

$T_x=\sqrt{T_x},T_y=\sqrt{T_y},T_{45}=\sqrt{T_{45}},T_{315}=\sqrt{T_{315}}$

(3), in the algorithm, select the highest output of template Grad as edge pixel intensity gradient:

$G=max\left(G\right)=\sqrt{{\mathrm{\Δ}}_{mx}G{(ax,by)}^2+{\mathrm{\ΔG}}_{ny}{(ax,by)}^2}$

For providing comparatively accurate edge gradient direction, implementation is:

$\mathrm{\θ}=arctan\frac{G_{by}}{G_{ax}}$

Wherein NE45 °, the edge detection results in NE315 ° direction is (as Fig. 2):

Δ _x+yG(Y-315°-X)＝ΔGx+ΔGy

Δ _x-yG(X-45°-Y)＝ΔGx-ΔGy

Step 4: process obtains any direction Sobel operator, comprises following four steps:

(1), according to four principal direction edge detection results, every 22.5 ° from fourth quadrant to first quartile, namely W270 °, NW292.5 °, NW315 °, NE337.5 °, N0 °, NE22.5 °, NE45 °, NE67.5 °, a NE90 ° further superposition calculation obtain isotropy operator template, and calculate total Grad and gradient direction, to often up and down, left and right adjoint point intensity-weighted is poor, when reaching extreme value in edge, just Edge detected is decided to be when extreme value and threshold value, there is provided comparatively accurate edge directional information (as Fig. 2), computing formula is as follows simultaneously;

Δ _x+yG(Y-337.5°-X)＝ΔGx+2ΔGy

Δ _x-yG(X-22.5°-Y)＝2ΔGx-ΔGy

Δ _x+yG(Y-292.5°-X)＝2ΔGx+ΔGy

Δ _x-yG(X-67.5°-Y)＝ΔGx-2ΔGy

Δ _x+yG(Y-m°-X)＝aΔGx+bΔGy

Δ _x-yG(X-n°-Y)＝bΔGx-aΔGy

In formula: wherein G (x, y) represents the amplitude data values that seismic data volume (x, y) is put, Δ _xg (x, y) and Δ _yg (x, y) is respectively the matrix that the data difference XOR detected through transverse direction and longitudinal edge is two group 3 × 3, Δ _x-yg (X-45 °-Y) and Δ _x+ythe data difference XOR that G (Y-315 °-X) is respectively NE45 ° and NW315 ° of rim detection is the matrix of two group 5 × 5, Δ _x+yg (Y-m °-X) and Δ _x-ythe data difference that G (X-n °-Y) is any direction rim detection, m, n are arbitrarily angled, and a, b are superposition coefficient, and superposition coefficient is integer, and G is the transverse direction of each point of data and longitudinal gradient approximation, and θ is gradient direction;

(2) threshold value, automatically obtaining best edge is the key of rim detection, threshold value is too low, false edges can be produced, and edge is thick, threshold value is too high, and edge can not effectively be detected or produce false phenomenon, for the typical method reducing false edge section quantity is to G (x, y) use a threshold value, all values lower than threshold value is composed null value;

(3), use described in step (2) rational threshold value, the main dual threshold algorithm improved that adopts carries out edge differentiation and is connected edge, first the gradient at edge is divided into multiple direction type: W270 °, NW292.5 °, NW315 °, NE337.5 °, N0 °, NE22.5 °, NE45 °, NE67.5 °, NE90 °, the different adjacent pixels of all directions compares, to determine local maximum, if the gray-scale value of certain pixel is not maximum compared with the gray-scale value of former and later two pixels on its gradient direction, so this pixel is set to zero, namely not marginal point, what every edge strength was greater than high threshold must be marginal point,

(4) the rational threshold value of the use, described in step (2), the main dual threshold algorithm improved that adopts carries out edge differentiation and is connected edge, and dual threshold algorithm is to non-maxima suppression image effect two threshold tau ₁and τ ₂, and 2 τ ₁≈ τ ₂, its relative error be less than 8%, obtain two threshold skirt image G ₁(x, y) and G ₂(x, y), dual-threshold voltage will at G ₂in (x, y), edge conjunction is become profile, when arriving the end points of profile, this algorithm is just at G ₁the edge that can be connected on profile is found in the 8 adjoint point positions of (x, y), and like this, algorithm is constantly at G ₁edge is collected, until by G in (x, y) ₁till (x, y) couples together (as Fig. 3);

Step 5: extract multi-direction rudimentary sequence strike-slip fault system, concrete grammar is as follows:

Adopt ant swarm algorithm, arrange suitable trace parameters, the ant calculating different directions tomography follows the trail of attribute volume, trail of the fault is extracted along aspect, obtain low-grade fault system diagram, rule of thumb extract strike-slip fault and lateral adjustments tomography, and quantitative statistics is carried out to parameters such as fault parameters.

Step 6: verify rudimentary sequence strike-slip fault reliability, comprises following two steps:

(1) the space three-dimensional tomographic systems, will obtained, contrast with the tomographic systems of the multiple dimensioned relevant extraction of routine, determine both goodnesses of fit, under the prerequisite that the high-level tomography goodness of fit is high, extract the lateral adjustments tomographic systems (as Fig. 4) between rudimentary sequence strike-slip fault and principal fault that on seismic section, turn-off is less than 10m, extended distance is less than 200m, lineups do not find obvious distortion;

(2), according to individual well dipmeter logging data, inclination angle integrated mode identification is adopted to cross well breakpoint, the reliability of tomography is extracted in checking, according to the variation tendency of meticulous stratum comparative analysis tomography two disc thickness, the reliability of tomography is extracted in checking, as misfitted with development behavior situation or not meeting geology development models, then comes back to step 3, if rationally, then judge the mechanical property of tomography further and walk sliding amount size.

Claims (7)

1. the seismic identification of the rudimentary sequence strike-slip fault in complex structural area, step is as follows:

Step 1: analyze poststack seismic data quality

Step 2: process acquisition advantage frequency-shared phase band

Step 3: process obtains principal direction Sobel operator

Step 4: process obtains any direction Sobel operator

Step 5: extract multi-direction rudimentary sequence strike-slip fault system

Step 6: verify rudimentary sequence strike-slip fault reliability.

2. the seismic identification of the rudimentary sequence strike-slip fault in complex structural area according to claim 1, it is characterized in that, step 1 concrete grammar is as follows: collect existing poststack time domain or Depth Domain seismic data, load existing interpre(ta)tive system, determine and follow the trail of objective interval reflection interval at the bottom of three-dimensional top of Water demand, obtain object short time-window data volume, carry out short window discrete Fourier transform or Maximum Entropy Spectral Estimation, generated frequency territory phase spectrum data volume.

3. the seismic identification of the rudimentary sequence strike-slip fault in the complex structural area according to claim 1-2, it is characterized in that, step 2 concrete grammar is as follows: on seismic interpretation Visualization Platform, observe different frequency section and delayed phase distribution, choose principal fault display clear, the obvious phase slices of primary and secondary fault complex is as dominant frequency phase slices, lead, the statistical study of secondary tomographic systems parameter, rule of thumb, that determines strike-slip fault or lateral adjustments tomography moves towards interval or scope, extract the earthquake advantage phase place frequency band obtaining and can reflect below 25m turn-off, and carry out normal state smoothing processing elimination Gibbs phenomenon.

4. the seismic identification of the rudimentary sequence strike-slip fault in the complex structural area according to claim 1-3, is characterized in that, step 3 comprises following three steps:

(1), the operator that the dominant frequency band seismic data giving prominence to low-grade fault after process carries out based on comprising two group of 3 × 3 matrix is calculated, planar convolution computing is done again with often some seismic amplitude data, draw horizontal and longitudinal data difference approximate value, represent raw data with A, Δ _xg (x, y) and Δ _yg (x, y) represents the data variation value detected through transverse direction and longitudinal edge respectively, and computing formula is as follows:

${\mathrm{\Δ}}_{x}G(x,Y)=\[G(x-1,y+1)+2G(x,y+1)+G(x+1,y+1)\]-\[G(x-1,y-1)+2G(x,y-1)+G(x+1,y-1)\]$

$=\left[\begin{array}{ccc}-1& 0& 1\\ -2& 0& 2\\ -1& 0& 1\end{array}\right]\·A$

${\mathrm{\Δ}}_{y}G(x,Y)=\[G(x-1,y-1)+2G(x-1,y)+G(x-1,y+1)\]-\[G(x+1,y-1)+2G(x+1,y)+G(x+1,y+1)\]$

$=\left[\begin{array}{ccc}-1& -2& -1\\ 0& 0& 0\\ 1& 2& 1\end{array}\right]\·A$

Its convolution mask operator is as follows:

$T_x=\left[\begin{array}{ccc}-1& 0& 1\\ -2& 0& 2\\ -1& 0& 1\end{array}\right],$ $T_y=\left[\begin{array}{ccc}-1& -2& -1\\ 0& 0& 0\\ 1& 2& 1\end{array}\right]$

(2), carry out squelch process, based on transverse direction, longitudinal edge operator, superposition obtains the operator template T of the size 5 × 5 in transverse direction, longitudinal direction, NE45 °, NE315 ° four principal directions _x, T _y, T ₄₅, T ₃₁₅, and root side is opened to each matrix operator obtain matrix isotropy Sobel operator, the weight location of each template is by the distance G (x of place-centric, y) and the direction of position determined, equidistant points has identical weight, to spiral amplitude data with four principal direction operator templates, total Grad G obtains by increasing by two inclination matrixes, obtains data exception edge by dual threshold algorithm:

$T_x=\left[\begin{array}{ccccc}2& 3& 0& -3& -2\\ 3& 4& 0& -4& -3\\ 6& 6& 0& -6& -6\\ 3& 4& 0& -4& -3\\ 2& 3& 0& -3& -2\end{array}\right],$ $T_y=\left[\begin{array}{ccccc}2& 3& 6& 3& 2\\ 3& 4& 6& 4& 3\\ 0& 0& 0& 0& 0\\ -3& -4& -6& -4& -3\\ -2& -3& -6& -3& -2\end{array}\right]$

$T_{45}=\left[\begin{array}{ccccc}0& -2& -3& -2& -6\\ 2& 0& -4& -6& -2\\ 3& 4& 0& -4& -3\\ 2& 6& 4& 0& -2\\ 6& 2& 3& 2& 0\end{array}\right],$ $T_{135}=\left[\begin{array}{ccccc}-6& -2& -3& -2& 0\\ -2& -6& -4& 0& 2\\ -3& -4& 0& 4& 2\\ -2& 0& 4& 6& 2\\ 0& 2& 3& 2& 6\end{array}\right]$

$T_x=\sqrt{T_x},T_y=\sqrt{T_y},T_{45}=\sqrt{T_{45}},T_{315}=\sqrt{T_{315}}$

(3), in the algorithm, select the highest output of template Grad as edge pixel intensity gradient:

$G=max\left(G\right)=\sqrt{{\mathrm{\Δ}}_{mx}G{(ax,by)}^2+{\mathrm{\ΔG}}_{ny}{(ax,by)}^2}$

For providing comparatively accurate edge gradient direction, implementation is:

$\mathrm{\θ}=\arctan \frac{G_{by}}{G_{ax}}$

Wherein NE45 °, the edge detection results in NE315 ° direction is:

Δ _x+yG(Y‐315°‐X)＝ΔGx+ΔGy

Δ _x‐yG(X‐45°‐Y)＝ΔGx‐ΔGy。

5. the seismic identification of the rudimentary sequence strike-slip fault in the complex structural area according to claim 1-4, is characterized in that, step 4 comprises following four steps:

(1), according to four principal direction edge detection results, every 22.5 ° from fourth quadrant to first quartile, namely W270 °, NW292.5 °, NW315 °, NE337.5 °, N0 °, NE22.5 °, NE45 °, NE67.5 °, NE90 °, further superposition calculation obtains isotropy operator template, and calculate total Grad and gradient direction, to often up and down, left and right adjoint point intensity-weighted is poor, when reaching extreme value in edge, just Edge detected is decided to be when extreme value and threshold value, there is provided comparatively accurate edge directional information, computing formula is as follows simultaneously;

Δ _x+yG(Y‐337.5°‐X)＝ΔGx+2ΔGy

Δ _x‐yG(X‐22.5°‐Y)＝2ΔGx‐ΔGy

Δ _x+yG(Y‐292.5°‐X)＝2ΔGx+ΔGy

Δ _x‐yG(X‐67.5°‐Y)＝ΔGx‐2ΔGy

Δ _x+yG(Y‐m°‐X)＝aΔGx+bΔGy

Δ _x‐yG(X‐n°‐Y)＝bΔGx‐aΔGy

In formula: wherein G (x, y) represents the amplitude data values that seismic data volume (x, y) is put, Δ _xg (x, y) and Δ _yg (x, y) is respectively the matrix that the data difference XOR detected through transverse direction and longitudinal edge is two group 3 × 3, Δ _{x ?y}g (X ?45 ° ?Y) and Δ _x+ythe data difference XOR that G (Y ?315 ° of ?X) is respectively NE45 ° and NW315 ° of rim detection is the matrix of two group 5 × 5, Δ _x+yg (Y ?m ° ?X) and Δ _{x ?y}the data difference that G (X ?n ° ?Y) is any direction rim detection, m, n are arbitrarily angled, and a, b are superposition coefficient, and superposition coefficient is integer, and G is the transverse direction of each point of data and longitudinal gradient approximation, and θ is gradient direction;

(2) threshold value, automatically obtaining best edge is the key of rim detection, threshold value is too low, false edges can be produced, and edge is thick, threshold value is too high, and edge can not effectively be detected or produce false phenomenon, for the typical method reducing false edge section quantity is to G (x, y) use a threshold value, all values lower than threshold value is composed null value;

(3), use described in step (2) rational threshold value, the main dual threshold algorithm improved that adopts carries out edge differentiation and is connected edge, first the gradient at edge is divided into polytype: W270 °, NW292.5 °, NW315 °, NE337.5 °, N0 °, NE22.5 °, NE45 °, NE67.5 °, NE90 °, the different adjacent pixels of all directions compares, to determine local maximum, if the gray-scale value of certain pixel is not maximum compared with the gray-scale value of former and later two pixels on its gradient direction, so this pixel is set to zero, namely not marginal point, what every edge strength was greater than high threshold must be marginal point,

(4) the rational threshold value of the use, described in step (2), the main dual threshold algorithm improved that adopts carries out edge differentiation and is connected edge, and dual threshold algorithm is to non-maxima suppression image effect two threshold tau ₁and τ ₂, and 2 τ ₁≈ τ ₂, its relative error be less than 8%, obtain two threshold skirt image G ₁(x, y) and G ₂(x, y), dual-threshold voltage will at G ₂in (x, y), edge conjunction is become profile, when arriving the end points of profile, this algorithm is just at G ₁the edge that can be connected on profile is found in the 8 adjoint point positions of (x, y), and like this, algorithm is constantly at G ₁edge is collected, until by G in (x, y) ₁till (x, y) couples together.

6. the seismic identification of the rudimentary sequence strike-slip fault in the complex structural area according to claim 1-5, it is characterized in that, step 5 concrete grammar is as follows: adopt ant swarm algorithm, suitable trace parameters is set, the ant calculating different directions tomography follows the trail of attribute volume, extracts trail of the fault, obtain low-grade fault system diagram along aspect, rule of thumb extract strike-slip fault and lateral adjustments tomography, and quantitative statistics is carried out to parameters such as fault parameters.

7. the seismic identification of the rudimentary sequence strike-slip fault in the complex structural area according to claim 1-6, is characterized in that, step 6 comprises following two steps:

(1) the space three-dimensional tomographic systems, will obtained, contrast with the tomographic systems of the multiple dimensioned relevant extraction of routine, determine both goodnesses of fit, under the prerequisite that the high-level tomography goodness of fit is high, extract the lateral adjustments tomographic systems between rudimentary sequence strike-slip fault and principal fault that on seismic section, turn-off is less than 10m, extended distance is less than 200m, lineups do not find obvious distortion;

(2), according to individual well dipmeter logging data, inclination angle integrated mode identification is adopted to cross well breakpoint, the reliability of tomography is extracted in checking, according to the variation tendency of meticulous stratum comparative analysis tomography two disc thickness, the reliability of tomography is extracted in checking, as misfitted with development behavior situation or not meeting geology development models, then comes back to step 3, if rationally, then judge the mechanical property of tomography further and walk sliding amount size.