CN105223607A - Based on the diffracted wave formation method of anti-steady phase filtering - Google Patents
Based on the diffracted wave formation method of anti-steady phase filtering Download PDFInfo
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Abstract
The invention belongs to seismic data migration imaging disposal route field, specifically a kind of Diffraction Imaging method based on anti-steady phase filtering improving the imaging resolution of heterogeneous body diffraction objective body.Its scheme is after obtaining seismic data, conventional prestack Kirchhoff skew is carried out to big gun record and obtains all-wave field imaging section, utilize plane wave structures filtering technique from the imaging results of all-wave field, extract the obliquity information of each imaging point, the obliquity information of utilization extraction builds anti-steady phase filter and it can be used as prestack Kirchhoff skew weight function can obtain only containing the migration result of diffraction energy.The present invention by introducing anti-steady phase filter in conventional Kirchhoff skew, the mirror-reflection meeting Snell law is effectively suppressed, diffraction energy is retained, thus improve the imaging resolution of heterogeneous body diffraction objective body, contributing to the Explanation Accuracy improving seismic data, is that a kind of practical and easy to operate diffracted wave is separated and imaging technique.
Description
Technical field
The present invention relates to seismic data migration imaging disposal route field, specifically a kind of Diffraction Imaging method based on anti-steady phase filtering improving the imaging resolution of heterogeneous body diffraction objective body.
Background technology
The seismic response waveform of researching value is had most mainly to comprise reflection wave and diffracted wave two class in seismologic record.Saying of narrow sense, the formation condition of reflection wave and diffracted wave depends primarily on the relation between geologic body yardstick and seismic event wavelength: when the yardstick of geologic body is much larger than seismic event wavelength, produces reflection wave; When geologic body yardstick and seismic event wavelength are quite or when being less than seismic event wavelength, produce diffracted wave.As can be seen here, when running into the inhomogeneous formations such as medium sudden change or horizontal noncontinuity structure in seismic wave propagation process, diffracted wave will be produced.In seismic prospecting, structure elucidation, lithologic interpretation and In Oil Field Exploration And Development phase fine are described to the diffracted wave information of the heterogeneous body destination media main manifestations horn of plenty of the stratum such as noncontinuity medium and the stratigraphic pitch-out sudden change media such as vital tomography, river course, salt dome border etc.Therefore, correctly identify heterogeneous body diffraction objective body and and improve it to describe precision be one of key factor improving oilfield prospecting developing level.
But, present stage, traditional data processing or skew are usually intended to imaging and strengthen reflected energy, in some conventional process flow, often there is the following unfavorable factor what time to diffraction target imaging: 1) in the process such as NMO/DMO, velocity analysis, be usually all regarded as interfering noise filtering from the lineups beyond reflection horizon; 2) conventional migration algorithm is mostly intended to imaging minute surface reflective information, and such as, kirchhoff skew hypothesis high frequency or stationary phase approach usually, even if traditional diffraction stack is also more prone to imaging reflection wave and ignores scattering effect; 3) on seismic section, weak one to two orders of magnitude of usual diffraction amplitude relative reflection ripple, even if by its migration, usually also can cover by reflective information.
Summary of the invention
The present invention seeks to for prior art Problems existing, a kind of Diffraction Imaging method based on anti-steady phase filtering improving heterogeneous body diffraction objective body imaging resolution is provided, the method makes full use of the diffraction information in geological data, realize the independent imaging of diffracted wave, with conventional full wave field imaging results joint interpretation, greatly effectively improve the precision of seismic interpretation.
Overall technological scheme of the present invention comprises:
1) conventional seismic data is adopted;
2) Kirchhoff pre-stack time migration is done to seismic data and obtain all-wave field imaging section;
3) using planar ripple destructing filtering mode extracts the reflector dip information of each imaging point from the all-wave field imaging results that step 2 obtains;
4) obliquity information of step 3 is utilized to build kernel function;
5) kernel function utilizing step 4 to obtain builds following anti-steady phase filter;
6) weight function that the anti-steady phase filter in step 5 offsets as Kirchhoff is carried out double offset to original big gun record, realize the independent imaging of final diffracted wave.
Technical scheme of the present invention comprises further:
1) conventional seismic data (prestack big gun record) is adopted;
2) Kirchhoff pre-stack time migration is done to prestack big gun record and obtain all-wave field imaging section.Theoretical based on diffraction stack, the mathematic(al) representation of Kirchhoff skew is as follows:
I (t, x)=∫ dtdsdr ω (s, x, r) U (t, s, r) δ (t-T (s, x, r)) (formula 1)
In formula: U (t, s, r) represents all-wave field pre stack data; T (s, x, r) represents the two-way time calculated by double square root equation; ω (s, x, r) is that Kirchhoff offsets weight function, different weight functions can be selected, as ω (s, x according to different objects, when r)=1, above formula and traditional diffraction stack migration, obtain all-wave field (comprising diffracted wave and reflection wave) imaging results;
3) the reflector dip information at using planar ripple destructing filtering technique each imaging point place of middle extraction from all-wave field imaging results I (t, x) that step 2 obtains.Plane wave destructing wave filter utilizes Local plane wave to superpose and characterizes geological data, time-space domain (T-X) simulation of spatial domain (F-X) prediction error filter frequently can be counted as, can estimate the local obliquity information of level and smooth lineups continuously preferably, its mathematic(al) representation is as follows:
C (σ) d ≈ 0 (formula 2)
In formula: C (σ) represents inclination angle, local predictive error operator, and d represents all-wave field imaging section.Solve the slope local estimation that the least square problem shown in formula 2 can realize all-wave field imaging section.
4) obliquity information utilizing step 3 to estimate builds following kernel function:
S (s, x, r)=| n
tt
x|/|| T
x|| (formula 3)
In formula: T
xrepresent the partial derivative of ray whilst on tour T (s, x, r) about imaging point; N represents the interface normal at each imaging point place, and the interface dip information can tried to achieve by step 3 obtains.0≤S≤1, for mirror-reflection, the value of formula 3 is close to 1, and for the diffraction outside mirror-reflection, the value of formula 3 is less than 1, and this kernel function therefore can be utilized to realize reflection and being separated of diffracted wave field;
5) kernel function utilizing step 4 to obtain builds following anti-steady phase filter:
In formula: S is kernel function shown in (3) formula, δ
1and δ
2be two threshold values, relevant with seismic band, for controlling the size of Fresnel-zone, general δ
2for be less than but close to 1 value, representative reflection excision lower bound; δ
1for diffraction retains the upper bound.
6) the anti-steady phase filter in step 5 is carried out double offset as the weight function of Kirchhoff skew (formula 1) to original big gun record and can realize the independent imaging of final diffracted wave.
The present invention using diffracted wave as important information, by introducing anti-steady phase filter in traditional Kirchhoff migration operator, the mirror-reflection meeting Snell law is effectively suppressed, diffraction energy is retained, the independent imaging section of final diffracted wave has the few advantage of skew noise, thus effectively improves the imaging resolution of heterogeneous body diffraction objective body.
Accompanying drawing explanation
Fig. 1 tests depression modeling velocity space used;
Fig. 2 is the single shot record extracted at Fig. 1 vertical line position place;
Fig. 3 utilizes plane wave destructing filtering technique to estimate the lineups slope section obtained;
Fig. 4 is the all-wave field imaging section that the conventional Kirchhoff pre-stack time migration of application obtains;
Fig. 5 is the independent imaging results of diffracted wave field that application the present invention obtains.
Embodiment
Based on a Diffraction Imaging method for anti-steady phase filtering, specifically comprise following:
1) conventional seismic data (prestack big gun record) is adopted;
2) Kirchhoff pre-stack time migration is done to prestack big gun record and obtain all-wave field imaging section.Theoretical based on diffraction stack, the mathematic(al) representation of Kirchhoff skew is as follows:
I (t, x)=∫ dtdsdr ω (s, x, r) U (t, s, r) δ (t-T (s, x, r)) (formula 1)
In formula: U (t, s, r) represents all-wave field pre stack data; T (s, x, r) represents the two-way time calculated by double square root equation; ω (s, x, r) is that Kirchhoff offsets weight function, different weight functions can be selected, as ω (s, x according to different objects, when r)=1, above formula and traditional diffraction stack migration, obtain all-wave field (comprising diffracted wave and reflection wave) imaging results;
3) the reflector dip information at using planar ripple destructing filtering technique each imaging point place of middle extraction from all-wave field imaging results I (t, x) that step 2 obtains.Plane wave destructing wave filter utilizes Local plane wave to superpose and characterizes geological data, time-space domain (T-X) simulation of spatial domain (F-X) prediction error filter frequently can be counted as, can estimate the local obliquity information of level and smooth lineups continuously preferably, its mathematic(al) representation is as follows:
C (σ) d ≈ 0 (formula 2)
In formula: C (σ) represents inclination angle, local predictive error operator, and d represents all-wave field imaging section.Solve the slope local estimation that the least square problem shown in formula 2 can realize all-wave field imaging section.
4) obliquity information utilizing step 3 to estimate builds following kernel function:
S (s, x, r)=| n
tt
x|/|| T
x|| (formula 3)
In formula: T
xrepresent the partial derivative of ray whilst on tour T (s, x, r) about imaging point; N represents the interface normal at each imaging point place, and the interface dip information can tried to achieve by step 3 obtains.0≤S≤1, for mirror-reflection, the value of formula 3 is close to 1, and for the diffraction outside mirror-reflection, the value of formula 3 is less than 1, and this kernel function therefore can be utilized to realize reflection and being separated of diffracted wave field;
5) kernel function utilizing step 4 to obtain builds following anti-steady phase filter:
In formula: S is kernel function shown in (3) formula, δ
1and δ
2be two threshold values, relevant with seismic band, for controlling the size of Fresnel-zone, general δ
2for be less than but close to 1 value, representative reflection excision lower bound; δ
1for diffraction retains the upper bound.
6) the anti-steady phase filter in step 5 is carried out double offset as the weight function of Kirchhoff skew (formula 1) to original big gun record and can realize the independent imaging of final diffracted wave.
For making technical scheme of the present invention and advantage become apparent, cited below particularly go out preferred embodiments, and coordinate institute's accompanying drawings, be described in detail below.
1) choose depression model to test, this model is 900 CDP points laterally, and longitudinally 380 sampled points, are 10m to sampling interval, as shown in Figure 1 in length and breadth;
2) recording geometry used is that split shooting both sides receive, shot interval 20m, maximum offset 1500m, track pitch 20m.Choose single shot record in Fig. 1 vertical line position and be shown in Fig. 2, above three obvious lineups representative reflections, below the 3rd reflection line-ups, have many weak diffraction lineups, not easy to identify owing to being covered by strong reflected energy;
3) all-wave field imaging results is obtained to above-mentioned big gun record applying equation 1 and be shown in Fig. 4;
4) Figure 3 shows that and utilize plane wave destructing filtering technique to be estimated the lineups slope local section obtained by all-wave field imaging results (Fig. 4);
5) utilize the obliquity information shown in Fig. 3, build anti-steady phase filter according to formula 4, this wave filter is offset weight function as Kirchhoff and can obtain the independent imaging results of diffracted wave shown in Fig. 5, wherein δ
1=0.8, δ
2=0.9.
Comparison diagram 4 and Fig. 5, (Fig. 4) covering due to strong reflected energy in the imaging results of all-wave field, the weak diffraction energy of depression both wings is not easy to identify; In the independent imaging section of diffracted wave that this invention of application obtains (Fig. 5), reflected energy from flat reflector and concave bottom flat seam is greatly suppressed, the inclined reflection energy of depression both wings have also been obtained corresponding compacting, thus make the small breakpoint of depression both wings ability be retained and give prominence to, thus demonstrate correctness of the present invention and feasibility.
Claims (3)
1., based on the diffracted wave formation method of anti-steady phase filtering, it is characterized in that comprising:
1) conventional seismic data is adopted;
2) Kirchhoff pre-stack time migration is done to seismic data and obtain all-wave field imaging section;
3) using planar ripple destructing filtering mode extracts the reflector dip information of each imaging point from the all-wave field imaging results that step 2 obtains;
4) obliquity information of step 3 is utilized to build kernel function;
5) kernel function utilizing step 4 to obtain builds following anti-steady phase filter;
6) weight function that the anti-steady phase filter in step 5 offsets as Kirchhoff is carried out double offset to original big gun record, realize the independent imaging of final diffracted wave.
2. the diffracted wave formation method based on anti-steady phase filtering according to claim 1, is characterized in that comprising further:
1) conventional prestack big gun record seismic data is adopted;
2) do Kirchhoff pre-stack time migration to prestack big gun record and obtain all-wave field imaging section, theoretical based on diffraction stack, the mathematic(al) representation of Kirchhoff skew is as follows:
(formula 1)
In formula:
represent all-wave field pre stack data;
represent the two-way time calculated by double square root equation;
that Kirchhoff offsets weight function; When
when=1, obtain the all-wave field imaging results comprising diffracted wave and reflection wave;
3) using planar ripple destructing wave filter is from the all-wave field imaging results that step 2 obtains
the reflector dip information at each imaging point place of middle extraction, its mathematic(al) representation is as follows:
(formula 2)
In formula:
represent inclination angle, local predictive error operator,
represent all-wave field imaging section, the least square problem solving formula 2 can realize the slope local estimation of all-wave field imaging section;
4) obliquity information utilizing step 3 to estimate builds following kernel function:
(formula 3)
In formula:
represent ray whilst on tour
about the partial derivative of imaging point;
represent the interface normal at each imaging point place, the interface dip information of being tried to achieve by step 3 obtains;
, for mirror-reflection, the value of formula 3 is close to 1, and for the diffraction outside mirror-reflection, the value of formula 3 is less than 1, therefore utilizes this kernel function to realize reflection and being separated of diffracted wave field;
5) kernel function utilizing step 4 to obtain builds following anti-steady phase filter:
(formula 4)
In formula:
for kernel function shown in (3) formula,
with
be two threshold values, relevant with seismic band, for controlling the size of Fresnel-zone,
for be less than but close to 1 value, representative reflection excision lower bound;
for diffraction retains the upper bound;
6) the anti-steady phase filter in step 5 is carried out double offset as the weight function of Kirchhoff skew (formula 1) to original big gun record, realize the independent imaging of final diffracted wave.
3. the diffracted wave formation method based on anti-steady phase filtering according to claim 2, is characterized in that, step 4 Kernel Function
span be
, two threshold values in step 5
with
traversal scope be
.
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| CN109143343A (en) * | 2018-11-14 | 2019-01-04 | 中国矿业大学(北京) | Diffraction wave imaging method, device and electronic equipment |
| CN110031900A (en) * | 2019-05-27 | 2019-07-19 | 中国矿业大学(北京) | Diffraction wave imaging method, device, electronic equipment and storage medium |
| CN111929732A (en) * | 2020-07-28 | 2020-11-13 | 中国石油大学(北京) | Seismic data denoising method, device and equipment |
| CN111929729A (en) * | 2020-08-20 | 2020-11-13 | 中国矿业大学(北京) | Diffracted wave imaging method and device and electronic equipment |
| CN113671573A (en) * | 2020-05-14 | 2021-11-19 | 中国石油化工股份有限公司 | Seismic data prestack diffracted wave separation method and device, electronic equipment and medium |
| CN115903043A (en) * | 2022-11-02 | 2023-04-04 | 中国矿业大学(北京) | Diffracted wave separation method and device |
| CN116088054A (en) * | 2023-03-07 | 2023-05-09 | 中国海洋大学 | Cross section homopolar axis discrimination method based on imaging gather |
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| CN108897036B (en) * | 2018-05-15 | 2020-04-10 | 中国石油天然气集团有限公司 | Seismic data processing method and device |
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| CN109143343A (en) * | 2018-11-14 | 2019-01-04 | 中国矿业大学(北京) | Diffraction wave imaging method, device and electronic equipment |
| CN110031900A (en) * | 2019-05-27 | 2019-07-19 | 中国矿业大学(北京) | Diffraction wave imaging method, device, electronic equipment and storage medium |
| CN113671573A (en) * | 2020-05-14 | 2021-11-19 | 中国石油化工股份有限公司 | Seismic data prestack diffracted wave separation method and device, electronic equipment and medium |
| CN111929732B (en) * | 2020-07-28 | 2021-09-03 | 中国石油大学(北京) | Seismic data denoising method, device and equipment |
| CN111929732A (en) * | 2020-07-28 | 2020-11-13 | 中国石油大学(北京) | Seismic data denoising method, device and equipment |
| CN111929729B (en) * | 2020-08-20 | 2021-04-06 | 中国矿业大学(北京) | Diffracted wave imaging method and device and electronic equipment |
| CN111929729A (en) * | 2020-08-20 | 2020-11-13 | 中国矿业大学(北京) | Diffracted wave imaging method and device and electronic equipment |
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| CN115903043A (en) * | 2022-11-02 | 2023-04-04 | 中国矿业大学(北京) | Diffracted wave separation method and device |
| CN115903043B (en) * | 2022-11-02 | 2024-03-15 | 中国矿业大学(北京) | Diffracted wave separation method and device |
| CN116088054A (en) * | 2023-03-07 | 2023-05-09 | 中国海洋大学 | Cross section homopolar axis discrimination method based on imaging gather |
| CN116088054B (en) * | 2023-03-07 | 2023-06-13 | 中国海洋大学 | Cross section homopolar axis discrimination method based on imaging gather |
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