阅读说明：本技术 降低邻炮相干性的自主扫描观测系统设计方法 (Design method of autonomous scanning observation system for reducing adjacent shot coherence ) 是由 胡立新 赵国勇 胡来东 霍守东 张剑 徐雷良 胡慧光 王春田 石太昆 王丙金 徐 于 2018-09-05 设计创作，主要内容包括：本发明提供一种降低邻炮相干性的自主扫描观测系统设计方法,包括：步骤1,根据勘探工区的实际情况,按照可控震源自主扫描高效采集的要求,划分震源车分布；步骤2,根据震源车的分布情况,构建震源激发延迟时间序列Γ；步骤3,将震源激发延迟时间序列Γ进行初始化；步骤4,依次将每台震源车的激发时间加入到时间序列Γ中,并更新Γ；步骤5,对整个时间序列Γ进行随机抖动微调,获得最优震源激发延迟时间序列。该降低邻炮相干性的自主扫描观测系统设计方法在可控震源的自主扫描中,从采集的角度降低邻炮干扰的相干性,从而为后续的邻炮干扰压制处理提供邻炮干扰能量最弱的地震记录,改善邻炮干扰的压制效果。(The invention provides a design method of an autonomous scanning observation system for reducing the coherence of adjacent shots, which comprises the following steps: step 1, dividing the distribution of seismic source vehicles according to the actual situation of an exploration work area and the requirement of autonomous scanning and efficient acquisition of a controllable seismic source; step 2, constructing a seismic source excitation delay time sequence gamma according to the distribution condition of the seismic source vehicles; step 3, initializing a seismic source excitation delay time sequence gamma; step 4, adding the excitation time of each seismic source vehicle into the time sequence gamma in sequence, and updating the gamma; and 5, carrying out random jitter fine adjustment on the whole time sequence gamma to obtain an optimal seismic source excitation delay time sequence. According to the design method of the autonomous scanning observation system for reducing the interference of the adjacent cannons, in the autonomous scanning of the controllable seismic sources, the interference of the adjacent cannons is reduced from the acquisition angle, so that the seismic record with the weakest interference energy of the adjacent cannons is provided for the subsequent interference suppression processing of the adjacent cannons, and the suppression effect of the interference of the adjacent cannons is improved.)

1. The design method of the autonomous scanning observation system for reducing the adjacent shot coherence is characterized by comprising the following steps:

step 1, dividing the distribution of seismic source vehicles according to the actual situation of an exploration work area and the requirement of autonomous scanning and efficient acquisition of a controllable seismic source;

step 2, constructing a seismic source excitation delay time sequence gamma according to the distribution condition of the seismic source vehicles;

step 3, initializing a seismic source excitation delay time sequence gamma;

step 4, adding the excitation time of each seismic source vehicle into the time sequence gamma in sequence, and updating the gamma;

and 5, carrying out random jitter fine adjustment on the whole time sequence gamma to obtain an optimal seismic source excitation delay time sequence.

2. The method for designing an autonomous scanning observation system capable of reducing the ortho-gun coherence of claim 1, wherein in step 3, the time when there is a source vehicle excitation is recorded as 1, the time when there is no source vehicle excitation is recorded as 0, and initialization is performed by recording all the times in the time series Γ as 0.

3. The method for designing an autonomous scanning observation system for reducing neighbor shot coherence according to claim 1, wherein in step 4, according to a compressed sensing theory, the maximum randomness of sampling is converted into the minimum maximum cross-correlation value between column vectors of a sparse transform matrix of a sampling matrix, and a sensing matrix is defined:

ψ F (formula 1)

Wherein, if F is sparse transform, the maximum cross-correlation value between column vectors of the sensing matrix is represented as:

according to the compressive sensing theory, the smaller mu is, the more irrelevant each quantity in the sampling matrix gamma is; therefore, the maximum cross-correlation value is reduced by changing the seismic source excitation delay time sequence, namely:

Γ ═ argmin μ (equation 3)

By optimizing the sampling matrix Γ, the sampling matrix with the smallest μ is the one that is sought.

4. The method for designing an autonomous scanning observation system capable of reducing the neighbor shot coherence in claim 3, wherein in step 4, the excitation time of each seismic source vehicle is added as follows:

① traversing all 0 positions in the time series gamma, calculating a new time series gamma 'after adding the excitation time of the seismic source vehicle, calculating the mu value of the new time series gamma' by using the formulas (1) and (2), and taking the seismic source excitation time which is the minimum of the mu value in all 0 positions as the new time series gamma;

②, the excitation time of each seismic source vehicle is added in turn, and the above steps are repeated for each seismic source vehicle until the excitation time of all seismic source vehicles is added to the time sequence.

5. The method for designing an autonomous scanning observation system capable of reducing the coherence of neighboring shots as claimed in claim 3, wherein in step 4, after the excitation time of all the source vehicles is added, a current time series Γ is obtained, then fine adjustment of random jitter is performed based on the excitation time of each source vehicle, μ values of the time series are calculated by using equations (1) and (2) for the result of each fine adjustment, if the μ values are reduced, the time series Γ is updated, otherwise, the time series Γ is not updated, that is: and (4) solving a time sequence gamma which enables the mu value to be minimum according to the formula (3), wherein the time sequence gamma is the solved optimal seismic source excitation delay time sequence.

Technical Field

The invention relates to the technical field of oil field development, in particular to a design method of an autonomous scanning observation system for reducing the adjacent shot coherence.

Background

At present, the design method of the autonomous scanning observation system of the controllable seismic source mainly comprises the following steps: 1) completely autonomous scanning, namely, completely random excitation is carried out without carrying out optimized design on a seismic source; 2) designing the seismic source scanning length, namely adding constraints of different scanning lengths to the seismic source so as to reduce the interference of adjacent shots; 3) nonlinear scanning-by using linear and nonlinear scanning methods, the interference coherence of adjacent shots is reduced. Therefore, a new design method of the autonomous scanning observation system for reducing the adjacent shot coherence is invented, and the technical problems are solved.

Disclosure of Invention

The invention aims to provide a design method of an autonomous scanning observation system for reducing the coherence of adjacent shots, which is convenient for suppressing the interference of the adjacent shots by optimizing the excitation delay time of a seismic source and reducing the coherence of the energy of the adjacent shots.

The object of the invention can be achieved by the following technical measures: the design method of the autonomous scanning observation system for reducing the adjacent shot coherence comprises the following steps: step 1, dividing the distribution of seismic source vehicles according to the actual situation of an exploration work area and the requirement of autonomous scanning and efficient acquisition of a controllable seismic source; step 2, constructing a seismic source excitation delay time sequence gamma according to the distribution condition of the seismic source vehicles; step 3, initializing a seismic source excitation delay time sequence gamma; step 4, adding the excitation time of each seismic source vehicle into the time sequence gamma in sequence, and updating the gamma; and 5, carrying out random jitter fine adjustment on the whole time sequence gamma to obtain an optimal seismic source excitation delay time sequence.

The object of the invention can also be achieved by the following technical measures:

in step 3, the time when the seismic source vehicle is excited is recorded as 1, the time when the seismic source vehicle is not excited is recorded as 0, and initialization is to record all the times on the time series Γ as 0.

In step 4, according to the compressed sensing theory, the maximum randomness of the sampling is converted into the minimum maximum cross correlation value among the column vectors of the sparse transformation matrix of the sampling matrix, and the sensing matrix is defined

ψ F (formula 1)

Wherein, F is sparse transformation, the maximum cross-correlation value between column vectors of the perception matrix is expressed as

According to the compressive sensing theory, the smaller mu is, the more irrelevant each quantity in the sampling matrix gamma is; thus, the maximum cross-correlation value is reduced by changing the source firing delay time sequence, i.e.

Γ ═ argmin μ (equation 3)

By optimizing the sampling matrix Γ, the sampling matrix with the smallest μ is the one that is sought.

In step 4, the adding manner of the excitation time of each seismic source vehicle is as follows:

① traversing all 0 positions in the time series gamma, calculating a new time series gamma 'after adding the excitation time of the seismic source vehicle, calculating the mu value of the new time series gamma' by using the formulas (1) and (2), and taking the seismic source excitation time which is the minimum of the mu value in all 0 positions as the new time series gamma;

②, the excitation time of each seismic source vehicle is added in turn, and the above steps are repeated for each seismic source vehicle until the excitation time of all seismic source vehicles is added to the time sequence.

In step 4, after the excitation time of all the seismic source vehicles is added, obtaining a current time series Γ, then performing fine adjustment of random jitter with the excitation time of each seismic source vehicle as a reference, calculating μ values of the time series by using equations (1) and (2) for the result of each fine adjustment, if the μ values are reduced, updating the time series Γ, otherwise, not updating, namely: and (4) solving a time sequence gamma which enables the mu value to be minimum according to the formula (3), wherein the time sequence gamma is the solved optimal seismic source excitation delay time sequence.

According to the design method of the autonomous scanning observation system for reducing the adjacent shot coherence, the seismic source excitation time sequence of autonomous scanning of the controllable seismic source is optimally designed according to the compressive sensing theory, and the observation system is optimized. By the optimization, the coherence of the interference energy of the adjacent shot is reduced to the maximum extent. By the design method of the autonomous scanning observation system for reducing the interference of the adjacent cannons, the interference of the adjacent cannons is reduced from the acquisition angle in the autonomous scanning of the controllable seismic source, so that the seismic record with the weakest interference energy of the adjacent cannons is provided for the subsequent interference suppression processing of the adjacent cannons, and the suppression effect of the interference of the adjacent cannons is improved.

Drawings

FIG. 1 is a flow chart of an embodiment of a method for designing an autonomous scanning observation system for reducing neighbor shot coherence according to the present invention;

FIG. 2 is a schematic diagram of a 6 × 3 vibroseis distribution in accordance with an embodiment of the present invention;

FIG. 3 is a time plane diagram of the firing of each source vehicle in an embodiment of the invention;

FIG. 4 is a time line diagram of the firing of source vehicles in accordance with an embodiment of the present invention;

fig. 5 is a spectrum diagram of fig. 4 after fourier transform according to an embodiment of the invention.

Detailed Description

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

As shown in fig. 1, fig. 1 is a flowchart of a design method of an autonomous scanning observation system for reducing neighbor shot coherence according to the present invention.

Step 101: and dividing the distribution of the seismic source vehicles according to the actual condition of the exploration work area and the requirement of autonomous scanning and efficient acquisition of the controllable seismic sources.

Step 102: and constructing a seismic source excitation delay time sequence gamma according to the distribution condition of the seismic source vehicles.

Step 103: initializing a seismic source excitation delay time sequence gamma, recording the time when a seismic source vehicle is excited as 1, recording the time when a non-seismic source vehicle is excited as 0, and recording all the times on the time sequence gamma as 0.

Step 104: and sequentially adding the excitation time of each seismic source vehicle into the time sequence gamma, and updating gamma.

The basic principle is as follows:

according to the compressed sensing theory, the maximum randomness of sampling can be converted into the 'maximum cross correlation value between column vectors of a sparse transformation matrix of a sampling matrix is minimum'. Assuming that the self-scanning seismic source excitation time delay forms a sampling matrix gamma, a perception matrix is defined

ψ F (formula 1)

Where F is sparse transform, the maximum cross-correlation value between column vectors of the sensing matrix can be expressed as

According to the compressed sensing theory, the smaller μ, the more incoherent the quantities in the sampling matrix Γ. Thus, the maximum cross-correlation value can be reduced by changing the source firing delay time sequence, i.e.

Γ ═ argmin μ (equation 3)

By optimizing the sampling matrix Γ, the sampling matrix with the smallest μ is the one that is sought.

The adding mode of the excitation time of each seismic source vehicle is as follows:

① traversing all 0 positions in the time series gamma, calculating a new time series gamma 'after adding the excitation time of the seismic source vehicle, calculating the mu value of the new time series gamma' by using the formulas (1) and (2), and taking the seismic source excitation time which is the minimum of the mu value in all 0 positions as the new time series gamma;

②, the excitation time of each seismic source vehicle is added in turn, and the above steps are repeated for each seismic source vehicle until the excitation time of all seismic source vehicles is added to the time sequence.

Step 105: adding all the excitation time of the seismic source vehicles to obtain a current time sequence gamma, then carrying out fine adjustment of random jitter by taking the excitation time of each seismic source vehicle as a reference, calculating a mu value of the time sequence by using formulas (1) and (2) for the result of each fine adjustment, if the mu value is reduced, updating the time sequence gamma, otherwise, not updating, namely: and (4) solving a time sequence gamma which enables the mu value to be minimum according to the formula (3), wherein the time sequence gamma is the solved optimal seismic source excitation delay time sequence.

In an embodiment applying the present invention, it is assumed that a work area divides the entire seismic source work area into 18 areas of 6 × 3 according to autonomous scanning, and each seismic source vehicle is responsible for the seismic source excitation of the corresponding area (as shown in fig. 2).

Assuming that the seismic source excitation time range of each seismic source vehicle is set to be 20s, namely 18 seismic source vehicles are excited in the 20s time range, the seismic source excitation time of each seismic source vehicle is made to be random as much as possible within the 20s time. Further, assuming that the design is performed based on the time interval dt of 0.5s, the obtained results are shown in fig. 3. FIG. 3 is a plan view of a seismic source firing time series of the final design, with the shades representing firing at different times; FIG. 4 is a display of the firing times of the source vehicles on a 20s time axis; fig. 5 is a spectral diagram of fig. 4 after fourier transform.

According to the method, the seismic source excitation time sequence of the autonomous scanning of the controllable seismic source is optimally designed according to the compressed sensing theory, and an observation system is optimized according to the optimal design. By the method, the coherence of adjacent shot interference can be greatly reduced from the acquisition angle in the autonomous scanning of the controllable seismic source, so that seismic records with minimum adjacent shot interference energy are provided for subsequent adjacent shot interference suppression processing, the suppression effect of adjacent shot interference is improved, accurate data are provided for fine reservoir prediction and oil-gas exploration, and an acquisition basis is provided for realizing the exploration purpose of 'two widths and one height'.