CN103984016A

CN103984016A - Converted wave anisotropy amplitude various angle gather extracting method

Info

Publication number: CN103984016A
Application number: CN201410232439.7A
Authority: CN
Inventors: 芦俊; 石瑛; 王赟
Original assignee: China University of Geosciences Beijing
Current assignee: China University of Geosciences Beijing
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2014-08-13
Anticipated expiration: 2034-05-28
Also published as: CN103984016B

Abstract

An embodiment of the present invention provides a converted wave anisotropic AVA gather extraction method, including: performing amplitude-preserving preprocessing on the PP wave; setting a depth domain offset grid, and selecting the first offset data according to the algorithm, By migrating the P-wave constant velocity, the CIG gather of the depth domain of the PP wave is obtained; the r-spectrum of the CIG gather is calculated to obtain the P-wave RMS velocity; the P-wave constant velocity is replaced by the P-wave RMS velocity, And iterate the above steps until the peak point of the r-spectrum completely converges to zero; select the second offset data, and obtain the CIG gather in the depth domain of the PP wave through P-wave constant velocity migration; calculate the CIG gather of the CIG gather g spectrum, get the anisotropy parameters of the PP wave; calculate the deep-time correspondence, convert the updated root mean square velocity of the P wave and the updated anisotropy parameters of the P wave to the time domain; extract the converted wave of the PP wave Gathering. The invention solves the problem of poor accuracy of the multi-wave AVA gather extraction method.

Description

Extraction Method of Converted Wave Anisotropic Amplitude Varying with Incident Angle

技术领域technical field

本发明涉及地震波技术领域，尤其涉及一种转换波各向异性振幅随入射角变化道集抽取方法。The invention relates to the technical field of seismic waves, in particular to a method for extracting a gather of converted wave anisotropy amplitude changing with incident angle.

背景技术Background technique

对于PS波各向异性来说，储层上方往往存在多套沉积地层，地层的非均匀性导致了地震波的速度存在各向异性，所以在抽取PS波各向异性的振幅随入射角变化(Amplitude Various Angle,AVA)道集时需要消除上覆地层地震波传播走时的各向异性，从而获得动校正较好的大排列多波AVA道集。For PS wave anisotropy, there are often multiple sets of sedimentary strata above the reservoir, and the heterogeneity of the strata leads to anisotropy in the velocity of seismic waves. Therefore, the amplitude of PS wave anisotropy varies with the incident angle (Amplitude Various Angle (AVA) gathers need to eliminate the anisotropy of seismic wave propagation travel time in the overlying formation, so as to obtain large array multi-wave AVA gathers with better dynamic correction.

但传统的多波AVA道集抽取方法常常采用PP波的共中心点(CommonMiddle Point,CMP)道集以及PS波的共转换点(Common Conversion Point,CCP)道集基于各向同性的速度谱进行AVA道集的转换，然后将PS波AVA道集进行压缩，以得到PP波T0时间域的PS波AVA道集。这种方法存在多个弊端：(a)道集没经过偏移，绕射波没有归位；(b)PS波AVA道集在压缩过程中会发生子波畸变现象，而且在道集上进行PS波压缩误差较大；(c)AVA道集排列较短，远偏移距发生弯曲。这些问题的存在都导致了传统的多波AVA道集抽取方法精度较差。However, the traditional multi-wave AVA gather extraction method usually uses the Common Middle Point (CMP) gather of PP waves and the Common Conversion Point (CCP) gather of PS waves based on the isotropic velocity spectrum. AVA gather conversion, and then compress the PS wave AVA gather to obtain the PS wave AVA gather in the PP wave T0 time domain. This method has many disadvantages: (a) the gathers have not been migrated, and the diffracted waves have not been homing; (b) the PS wave AVA gathers will have wavelet distortion during the compression process, and the The compression error of PS wave is large; (c) AVA gathers are arranged short, and the far offset is bent. The existence of these problems has led to the poor accuracy of the traditional multi-wave AVA gather extraction method.

发明内容Contents of the invention

本发明的主要目的在于提供一种转换波各向异性AVA道集抽取方法，以解决现有技术存在的多波AVA道集抽取方法精度较差的问题。The main purpose of the present invention is to provide a converted-wave anisotropic AVA gather extraction method to solve the problem of poor accuracy of the multi-wave AVA gather extraction method in the prior art.

为解决上述问题，本发明实施例提供一种转换波各向异性AVA道集抽取方法，包括：1)对PP波进行保幅预处理；2)设置深度域偏移网格，根据一演算法并选定第一偏移距数据，以通过P波常速度偏移，得到所述PP波的深度域的共成像点道集；3)计算所述共成像点道集的r谱，得到更新的P波均方根速度；4)将所述P波常速度替换成更新后的所述P波均方根速度，并叠代步骤2)、3)、4)，直至所述r谱的峰值点完全收敛于零；5)选定第二偏移距数据，通过所述P波常速度偏移，得到所述PP波的深度域的所述共成像点道集，其中所述第二偏移距数据大于所述第一偏移距数据；6)计算所述共成像点道集的g谱，得到更新的PP波的各向异性参数；7)根据所述更新后的P波均方根速度，计算深时对应关系，将更新后的所述P波均方根速度、更新后的所述P波的各向异性参数转换到时间域；8)抽取所述PP波的转换波道集。In order to solve the above problems, an embodiment of the present invention provides a method for extracting converted wave anisotropic AVA gathers, including: 1) performing amplitude-preserving preprocessing on PP waves; 2) setting a depth-domain migration grid, according to an algorithm And select the first offset data to obtain the common imaging point gather in the depth domain of the PP wave through P wave constant velocity migration; 3) calculate the r-spectrum of the common imaging point gather to obtain an updated 4) replace the P-wave constant velocity with the updated P-wave root-mean-square velocity, and iterate steps 2), 3), and 4) until the r-spectrum The peak point completely converges to zero; 5) the second offset data is selected, and the common imaging point gather of the depth domain of the PP wave is obtained through the P-wave constant velocity migration, wherein the second The offset data is greater than the first offset data; 6) calculate the g-spectrum of the common imaging point gather, and obtain the anisotropy parameter of the updated PP wave; 7) according to the updated P-wave average Square root velocity, calculate deep-time correspondence, convert the anisotropic parameters of the updated P-wave root-mean-square velocity and the updated P-wave to the time domain; 8) extract the converted wave of the PP wave Gathering.

其中，所述演算法包括如下公式： $t_{e} = {[\frac{z^{2} + h_{e}^{2}}{v_{m}^{2} (1 + g_{e} h_{e}^{2})}]}^{\frac{1}{2}};$ 2te＝t； $h_{e} = {[\frac{\frac{v_{m}^{2} t^{2}}{4} - z^{2}}{1 - \frac{v_{m}^{2} t^{2} g_{e}}{4}}]}^{\frac{1}{2}},$ 其中将所述PP波的所述各向异性参数置为0。Wherein, the algorithm includes the following formula: $t_{e} = {[\frac{z^{2} + h_{e}^{2}}{v_{m}^{2} (1 + g_{e} h_{e}^{2})}]}^{\frac{1}{2}};$ 2te = t; $h_{e} = {[\frac{\frac{v_{m}^{2} t^{2}}{4} - z^{2}}{1 - \frac{v_{m}^{2} t^{2} g_{e}}{4}}]}^{\frac{1}{2}},$ Wherein the anisotropy parameter of the PP wave is set to 0.

其中，所述计算所述共成像点道集的r谱，得到更新的P波均方根速度的步骤包括：基于公式计算所述共成像点道集的r谱，得到更新的P波均方根速度。Wherein, the step of calculating the r-spectrum of the common imaging point gather and obtaining the updated P-wave RMS velocity includes: based on the formula The r-spectrum of the common imaging point gather is calculated to obtain the updated RMS velocity of the P wave.

其中，所述计算所述共成像点道集的g谱，得到更新的PP波的各向异性参数的步骤包括：基于公式计算共成像点道集的g谱，得到更新的PP波的各向异性参数。Wherein, the step of calculating the g-spectrum of the common imaging point gather and obtaining the anisotropy parameter of the updated PP wave comprises: based on the formula The g-spectrum of the common imaging point gather is calculated to obtain the updated anisotropy parameters of the PP wave.

其中，所述根据所述更新后的P波均方根速度，计算深时对应关系，将更新后的所述P波均方根速度、更新后的所述P波的各向异性参数转换到时间域的步骤包括：基于公式计算深时对应关系，将更新后的所述P波均方根速度、更新后的所述P波的各向异性参数转换到时间域。Wherein, according to the updated root mean square velocity of the P wave, the deep-time corresponding relationship is calculated, and the updated root mean square velocity of the P wave and the anisotropy parameter of the updated P wave are converted into Steps in the time domain include: Based on the formula Calculating the deep-time correspondence, converting the updated root-mean-square velocity of the P-wave and the updated anisotropy parameter of the P-wave into the time domain.

其中，所述抽取所述PP波的转换波道集的步骤包括：基于公式抽取所述PP波的转换波道集。Wherein, the step of extracting the converted channel set of the PP wave comprises: based on the formula A converted channel set of the PP wave is extracted.

本发明实施例还提供一种转换波各向异性AVA道集抽取方法，包括：1)对PS波进行保幅预处理；2)设置深度域偏移网格公式，根据一演算法并选定第一移距数据，用PP波处理得到的P波均方根速度以及S波常速度偏移，得到所述PS波的深度域的共成像点道集；3)计算所述PS波的共成像点道集的r谱，得到更新的S波均方根速度；4)将所述S波常速度替换成更新后的所述S波均方根速度，并叠代步驟2)、3)、4)，直至r谱的峰值点完全收敛于零；5)选定第二偏移距数据，通过更新后的所述P波的各向异性参数，消除下行所述P波旅行时的各向异性，偏移得到所述PS波的深度域的共成像点道集，其中所述第二偏移距数据大于所述第一移距数据；6)计算所述PS波的所述共成像点道集的g谱，得到更新的所述PS波的各向异性参数；7)根据PP波深时对应关系，将更新后的所述S波均方根速度、更新后的所述PS波的各向异性参数转换到时间域；8)抽取所述PS波的转换波道集。The embodiment of the present invention also provides a method for extracting converted wave anisotropic AVA gathers, including: 1) performing amplitude-preserving preprocessing on the PS wave; 2) setting the offset grid formula in the depth domain, and selecting The first displacement data, the root mean square velocity of the P wave and the constant velocity migration of the S wave obtained by PP wave processing, obtain the common imaging point gather of the depth domain of the PS wave; 3) calculate the common imaging point gather of the PS wave The r-spectrum of the imaging point gather, obtain the updated S-wave root-mean-square velocity; 4) replace the S-wave constant velocity with the updated S-wave root-mean-square velocity, and iterate steps 2), 3) , 4), until the peak point of the r-spectrum completely converges to zero; 5) select the second offset data, and eliminate each of the downlink travel time of the P-wave through the anisotropic parameters of the updated P-wave Anisotropy, migration to obtain the common imaging point gather of the depth domain of the PS wave, wherein the second offset data is greater than the first offset data; 6) Calculate the common imaging of the PS wave The g-spectrum of the point gather obtains the anisotropic parameters of the PS wave updated; 7) according to the corresponding relationship between the PP wave depth and time, the updated S wave RMS velocity and the updated PS wave The anisotropic parameters of the transform to the time domain; 8) extracting the transformed channel set of the PS wave.

其中，所述计算所述PS波的共成像点道集的r谱，得到更新的S波均方根速度的步骤包括：基于公式计算所述PS波的共成像点道集的r谱，得到均方根速度，再根据公式换算，得到更新的S波均方根速度。Wherein, the step of calculating the r-spectrum of the common imaging point gather of the PS wave and obtaining the updated S-wave RMS velocity includes: based on the formula Calculate the r-spectrum of the common imaging point gather of the PS wave to obtain the root mean square velocity, and then according to the formula Conversion, to get the updated root mean square velocity of the S wave.

其中，所述计算所述PS波的所述共成像点道集的g谱，得到更新的所述PS波的各向异性参数的步骤包括：基于公式且将r置为0，计算所述PS波的所述共成像点道集的g谱，得到更新的各向异性参数，再根据公式换算，得到更新的PS波的各向异性参数。Wherein, the step of calculating the g-spectrum of the common imaging point gather of the PS wave and obtaining the updated anisotropy parameter of the PS wave includes: based on the formula And set r to 0, calculate the g spectrum of the common imaging point gather of the PS wave, obtain the updated anisotropy parameter, and then according to the formula Conversion, get the updated PS wave anisotropy parameters.

其中，所述根据PP波深时对应关系，将更新后的所述S波均方根速度、更新后的所述PS波的各向异性参数转换到时间域的步骤包括：基于公式计算深时对应关系，将更新后的所述P波均方根速度、更新后的所述P波的各向异性参数转换到时间域。Wherein, according to the corresponding relationship between PP wave depth and time, the step of converting the updated S-wave root mean square velocity and the updated PS wave anisotropy parameter into the time domain includes: based on the formula Calculating the deep-time correspondence, converting the updated root-mean-square velocity of the P-wave and the updated anisotropy parameter of the P-wave into the time domain.

其中，所述抽取所述PS波的转换波道集的步骤包括：基于公式抽取所述PS波的转换波道集。Wherein, the step of extracting the converted channel set of the PS wave comprises: based on the formula A converted channel set of the PS wave is extracted.

根据本发明的技术方案，通过在深度域利用P波与S波的偏移速度抽取共散射点(Common Scatter Point,CSP)道集，基于剩余曲率分析方法更新偏移速度与各向异性参数，并根据换算的成像深度实现PP波与PS波的层位匹配；将深度域分析得到的P波、S波偏移速度、各向异性参数换算到PP波T0时间域，通过叠前偏移与各向异性射线追踪的方法得到层位完全匹配的PP波与PS波AVA道集，使AVA道集抽取方法精度较佳。According to the technical solution of the present invention, by using the migration velocity of P wave and S wave to extract common scatter point (Common Scatter Point, CSP) gathers in the depth domain, the migration velocity and anisotropy parameters are updated based on the residual curvature analysis method, And according to the converted imaging depth, the layer matching between PP wave and PS wave is realized; the migration velocity and anisotropy parameters of P wave and S wave obtained from the depth domain analysis are converted to the PP wave T0 time domain, and through prestack migration and The method of anisotropic ray tracing obtains the PP-wave and PS-wave AVA gathers with fully matched horizons, which makes the AVA gather extraction method more accurate.

附图说明Description of drawings

此处所说明的附图用来提供对本发明的进一步理解，构成本申请的一部分，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。在附图中：The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

图1是根据本发明实施例的共散射点道集构建的示意图；Fig. 1 is a schematic diagram of constructing a common scattering point gather according to an embodiment of the present invention;

图2是根据本发明实施例的转换波道集抽取方法的流程图；FIG. 2 is a flow chart of a method for extracting converted channel sets according to an embodiment of the present invention;

图3是根据本发明另一实施例的转换波道集抽取方法的流程图；Fig. 3 is a flow chart of a method for extracting converted channel sets according to another embodiment of the present invention;

图4是根据本发明实施例的最终抽取的PP波的AVA道集的示意圖。Fig. 4 is a schematic diagram of an AVA gather of finally extracted PP waves according to an embodiment of the present invention.

图5是根据本发明实施例的最终抽取的PS波的AVA道集的示意图。Fig. 5 is a schematic diagram of an AVA gather of finally extracted PS waves according to an embodiment of the present invention.

具体实施方式Detailed ways

本发明的主要思想在于，基于散射原理，在深度域利用P波与S波的偏移速度抽取CSP道集，基于剩余曲率分析方法更新偏移速度与各向异性参数，并根据换算的成像深度实现PP波与PS波的层位匹配；将深度域分析得到的P波、S波偏移速度、各向异性参数换算到PP波T0时间域，通过叠前偏移与各向异性射线追踪的方法得到层位完全匹配的PP波与PS波AVA道集，使AVA道集抽取方法精度较佳。The main idea of the present invention is that, based on the principle of scattering, the migration velocity of P-wave and S-wave is used to extract CSP gathers in the depth domain, and the migration velocity and anisotropy parameters are updated based on the residual curvature analysis method, and according to the converted imaging depth Realize the horizon matching between PP wave and PS wave; convert the P wave and S wave migration velocity and anisotropy parameters obtained from the depth domain analysis to the PP wave T0 time domain, and use prestack migration and anisotropic ray tracing The method obtains PP wave and PS wave AVA gathers with completely matching horizons, so that the accuracy of AVA gather extraction method is better.

为使本发明的目的、技术方案和优点更加清楚，以下结合附图及具体实施例，对本发明作进一步地详细说明。In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

首先，当考虑地层垂向的分均匀性引发的各向异性时，PP波的时距方程可如公式(1.1)所示：First, when considering the anisotropy caused by the vertical uniformity of the formation, the time-distance equation of the PP wave can be expressed as formula (1.1):

${t t}_{PP PP} = = \sqrt{{t t}_{00 PP PP}^{22} + + \frac{{x x}_{P P}^{22}}{{v v}_{P P}^{22} ((11 + + {g g}_{P P} {x x}_{P P}^{22}))}},, - - - - - - ((1.1 1.1))$

其中，t_PP为PP波的旅行时，t_0PP为PP波的T0时间，x_P为PP波的炮点与中心点的水平距离，v_P为P波均方根速度，g_P为各向异性参数且表示为P波的垂向非均匀性。Among them, t _PP is the travel time of the PP wave, t _0PP is the T0 time of the PP wave, x _P is the horizontal distance between the shot point and the center point of the PP wave, v _P is the root mean square velocity of the P wave, and g _P is the Anisotropy parameter and expressed as the vertical inhomogeneity of the P wave.

对于PS波，下行波为P波，上行波为S波，则PS波时距方程可如公式(1.2)所示：For the PS wave, the downgoing wave is the P wave, and the upgoing wave is the S wave, then the time-distance equation of the PS wave can be shown in formula (1.2):

${t t}_{PS P.S.} = = \sqrt{{t t}_{00 P P}^{22} + + \frac{{x x}_{P P}^{22}}{{v v}_{P P}^{22} ((11 + + {g g}_{P P} {x x}_{P P}^{22}))}} + + \sqrt{{t t}_{00 S S}^{22} + + \frac{{x x}_{S S}^{22}}{{v v}_{S S}^{22} ((11 + + {g g}_{S S} {x x}_{S S}^{22}))}},, - - - - - - ((1.2 1.2))$

其中，t_PS为PS波的旅行时，t_0P、t_0S分别为P波、S波的单程垂直旅行时，x_P、x_S分别为炮点、接收点至转换点的水平距离，v_S为S波均方根速度，g_S为各向异性参数且表示为S波的垂向非均匀性。Among them, t _PS is the travel time of PS wave, t _0P , t _0S are the one-way vertical travel time of P wave and S wave respectively, x _P , x _S are the horizontal distances from shot point, receiving point to conversion point, v _S is the root mean square velocity of the S wave, g _S is the anisotropy parameter and is expressed as the vertical inhomogeneity of the S wave.

图1是根据本发明实施例的CSP道集构建的示意图，如图1所示，将地下介质模型离散成网格节点，每个节点即为散射点。其中，S表示为震源点，R表示为接收点；散射点(Scatter Point)的深度为Z，其在地表的投影为SP。地震波在散射点上方介质传播时，下行波与上行波偏移速度分别为v_d、v_u，震源与散射点之间的旅行时为t_d，散射点与接收点之间的旅行时为t_u，SP点到震源点S距离为d_s，SP点到接收点R之间的距离为d_r，一定能在震源点S与接收点R之间找到一等效偏移距点E，等效偏移距点与散射点之间的地震波旅行时t_e与t_s、t_r之间满足公式(1.3)，如下所示：Fig. 1 is a schematic diagram of CSP gather construction according to an embodiment of the present invention. As shown in Fig. 1 , the subsurface medium model is discretized into grid nodes, and each node is a scattering point. Among them, S represents the source point, R represents the receiving point; the depth of the scatter point (Scatter Point) is Z, and its projection on the surface is SP. When the seismic wave propagates in the medium above the scattering point, the migration velocity of the downgoing wave and the upgoing wave are v _d and v _u respectively, the travel time between the source and the scattering point is t _d , and the travel time between the scattering point and the receiving point is t _u , the distance from SP to source point S is d _s , and the distance from SP to receiver point R is d _r , an equivalent offset point E can be found between source point S and receiver point R, etc. The seismic wave travel time t _e between the effective offset point and the scattering point satisfies the formula (1.3) between t _s and t _r , as follows:

2t_e＝t_d+t_u＝t， (1.3)2t _e =t _d +t _u =t, (1.3)

其中，t为地震波总旅行时。Among them, t is the total travel time of seismic waves.

假设SR的中心点为MP，根据公式(1.1)、(1.2)，可得公式(1.4)，如下所示：Assuming that the center point of SR is MP, according to formulas (1.1) and (1.2), formula (1.4) can be obtained, as follows:

$t t = = {[[\frac{{z z}^{22} + + {d d}_{s the s}^{22}}{{v v}_{d d}^{22} ((11 + + {g g}_{s the s} {d d}_{s the s}^{22}))}]]}^{\frac{11}{22}} + + {[[\frac{{z z}^{22} + + {d d}_{r r}^{22}}{{v v}_{u u}^{22} ((11 + + {g g}_{r r} {d d}_{r r}^{22}))}]]}^{\frac{11}{22}},, - - - - - - ((1.4 1.4))$

之后，令SP与E点之间的距离为h_e之后，则(1.4)可转换成公式(1.5)，如下所示：After that, let the distance between SP and point E be he _e , then (1.4) can be transformed into formula (1.5), as shown below:

${t t}_{e e} = = {[[\frac{{z z}^{22} + + {h h}_{e e}^{22}}{{v v}_{m m}^{22} ((11 + + {g g}_{e e} {h h}_{e e}^{22}))}]]}^{\frac{11}{22}},, - - - - - - ((1.5 1.5))$

由於2t_e＝t，所以可得且由前述公式可得公式(1.6)，如下所示：Since 2t _e = t, we can get And the formula (1.6) can be obtained from the above formula, as follows:

${h h}_{e e} = = {[[\frac{\frac{{v v}_{m m}^{22} {t t}^{22}}{44} - - {z z}^{22}}{11 - - \frac{{v v}_{m m}^{22} {t t}^{22} {g g}_{e e}}{44}}]]}^{\frac{11}{22}} . . - - - - - - ((1.6 1.6))$

对于PP波，存在v_Pm＝v_d＝v_u＝v_m，则公式(1.6)变为公式(1.7)，如下所示：For PP waves, there exists v _Pm =v _d =v _u =v _m , then formula (1.6) becomes formula (1.7), as shown below:

$22 {[[\frac{{z z}^{22} + + {h h}_{e e}^{22}}{{v v}_{Pm PM}^{22} ((11 + + {g g}_{P P} {h h}_{e e}^{22}))}]]}^{\frac{11}{22}} = = {[[\frac{{z z}^{22} + + {d d}_{s the s}^{22}}{{v v}_{Pm PM}^{22} ((11 + + {g g}_{P P} {d d}_{s the s}^{22}))}]]}^{\frac{11}{22}} + + {[[\frac{{z z}^{22} + + {d d}_{r r}^{22}}{{v v}_{Pm PM}^{22} ((11 + + {g g}_{P P} {d d}_{r r}^{22}))}]]}^{\frac{11}{22}} . . - - - - - - ((1.7 1.7))$

对于PS波，令v_Pm＝v_d、v_Sm＝v_u、v_Cm＝v_m，则式(1.6)变为公式(1.7)，如下所示：For PS waves, let v _Pm = v _d , v _Sm = v _u , v _Cm = v _m , then formula (1.6) becomes formula (1.7), as shown below:

$22 {[[\frac{{z z}^{22} + + {h h}_{e e}^{22}}{{v v}_{Cm cm}^{22} ((11 + + {g g}_{C C} {h h}_{e e}^{22}))}]]}^{\frac{11}{22}} = = {[[\frac{{z z}^{22} + + {d d}_{s the s}^{22}}{{v v}_{Pm PM}^{22} ((11 + + {g g}_{P P} {d d}_{s the s}^{22}))}]]}^{\frac{11}{22}} + + {[[\frac{{z z}^{22} + + {d d}_{r r}^{22}}{{v v}_{Sm SM}^{22} ((11 + + {g g}_{S S} {d d}_{r r}^{22}))}]]}^{\frac{11}{22}},, - - - - - - ((11 . . 88))$

在公式(1.8)中，令公式(1.9)，如下所示：In formula (1.8), make formula (1.9) as follows:

$γ γ = = \frac{{v v}_{Pm PM}}{{v v}_{Sm SM}},, - - - - - - ((1.9 1.9))$

则可得公式(1.10)，如下所示：Then formula (1.10) can be obtained as follows:

${v v}_{Cm cm} = = \frac{22 {v v}_{Pm PM}}{11 + + γ γ} . . - - - - - - ((1.10 1.10))$

利用上述过程可以形成CSP道集，在CSP道集中的偏移距为等效偏移距。在CSP道集中各向异性地震记录的同相轴真实的双程旅行时可以表示为公式(1.11)，如下所示：The above process can be used to form a CSP gather, and the offset in the CSP gather is an equivalent offset. The event true two-way travel time of anisotropic seismic records in a CSP gather can be expressed as Equation (1.11), as follows:

${t t}_{{h h}_{e e}}^{22} = = {t t}_{00}^{22} + + \frac{44 {h h}_{e e}^{22}}{{v v}_{t t}^{22} ((11 + + {g g}_{e e} {h h}_{e e}^{22}))} . . - - - - - - ((1.11 1.11))$

在深度域，偏移时地震波双程旅行时可以表示为公式(1.12)，如下所示：In the depth domain, the seismic wave round-trip travel time during migration can be expressed as Equation (1.12), as follows:

${t t}_{{h h}_{e e}} = = \frac{22 {h h}_{e e}}{{v v}_{m m}} = = \frac{22}{{v v}_{m m} {((11 + + {g g}_{e e} {h h}_{e e}^{22}))}^{\frac{11}{22}}} \sqrt{{z z}^{22} + + {h h}_{e e}^{22}},, - - - - - - ((1.12 1.12))$

所以可将公式(1.12)转换成公式(1.13)，如下所示：So formula (1.12) can be transformed into formula (1.13) as follows:

${t t}_{{h h}_{e e}}^{22} = = \frac{44 (({z z}^{22} + + {h h}_{e e}^{22}))}{{v v}_{m m}^{22} ((11 + + {g g}_{e e} {h h}_{e e}^{22}))},, - - - - - - ((1.13 1.13))$

则不同等效偏移距h_e的成像深度为公式(1.14)，如下所示：Then the imaging depth of different equivalent offsets h _e is formula (1.14), as follows:

${z z}_{{h h}_{e e}}^{22} = = \frac{{v v}_{m m}^{22} ((11 + + {gh gh}^{22}))}{44} {t t}_{{h h}_{e e}}^{22} - - {h h}_{e e}^{22},, - - - - - - ((1.14 1.14))$

将公式(1.11)带入到公式(1.14)，可得成像深度与偏移速度误差满足如公式(1.15)的关系，如下所示：Substituting formula (1.11) into formula (1.14), it can be obtained that the error of imaging depth and migration velocity satisfies the relationship of formula (1.15), as follows:

${z z}_{{h h}_{e e}}^{22} = = {z z}_{00}^{22} + + {rh rh}^{22} + + {gh gh}^{22} {z z}_{00}^{22},, - - - - - - ((1.15 1.15))$

其中，in,

$\{\begin{matrix} {z z}_{00} = = \frac{{v v}_{m m} {t t}_{00}}{22} \\ r r = = ((\frac{{v v}_{m m}^{22}}{{v v}_{t t}^{22}} - - 11)) \end{matrix} - - - - - - ((1.16 1.16))$

由公式(1.15)可见，当偏移速度与真实速度相同且各向异性效应完全消除时偏移深度才能与真实地层深度吻合。基于公式(1.15)，可以用来抽取深度域的共成像点道集(Common Imaging Gather,CIG)，并通过r谱以及g谱扫描来找到真实的P、S波速度与各向异性参数，从而提高多波AVA道集抽取的精度。It can be seen from formula (1.15) that the migration depth can match the real formation depth only when the migration velocity is the same as the real velocity and the anisotropy effect is completely eliminated. Based on the formula (1.15), it can be used to extract the Common Imaging Gather (CIG) in the depth domain, and find the real P and S wave velocity and anisotropy parameters through r-spectrum and g-spectrum scanning, so that Improve the accuracy of multiwave AVA gather extraction.

由于PS波的传播同时受到P、S波速度以及各自各向异性参数的同时影响，所以PS波的处理必须在PP波之后。在获得真实的P波偏移速度域各向异性参数以后，首先消除P波各向异性的影响，再求取S波的偏移速度与各向异性参数。由于PS波的g谱扫描得到的各向异性参数为g_c，它与g_s之间存在差异。对于一定偏移距h，根据公式(1.10)，g_c与g_s的关系为公式(1.17)，如下所示：Since the propagation of PS wave is simultaneously affected by the velocity of P and S waves and their respective anisotropy parameters, the processing of PS wave must be done after PP wave. After obtaining the real anisotropy parameters of the P-wave migration velocity domain, the influence of the P-wave anisotropy is eliminated first, and then the migration velocity and anisotropy parameters of the S-wave are obtained. Since the anisotropy parameter obtained from the g-spectrum scanning of the PS wave is g _c , there is a difference between it and g _s . For a certain offset h, according to formula (1.10), the relationship between g _c and g _s is formula (1.17), as follows:

${v v}_{SM SM} {((11 + + {g g}_{S S} {h h}^{22}))}^{\frac{11}{22}} = = \frac{{v v}_{Pm PM} {v v}_{Cm cm} {((11 + + {g g}_{C C} {h h}^{22}))}^{\frac{11}{22}}}{22 {v v}_{P P} - - {v v}_{C C} {((11 + + {g g}_{C C} {h h}^{22}))}^{\frac{11}{22}}},, - - - - - - ((1.17 1.17))$

将公式(1.9)带入公式(1.17)，可得到公式(1.18)，如下所示：Substituting formula (1.9) into formula (1.17), formula (1.18) can be obtained as follows:

${g g}_{S S} = = {[[\frac{γ γ {((11 + + {g g}_{C C} {h h}^{22}))}^{\frac{11}{22}}}{\frac{γ γ + + 11}{h h} - - {((\frac{11}{{h h}^{22}} + + {g g}_{C C}))}^{\frac{11}{22}}}]]}^{22} - - \frac{11}{{h h}^{22}},, - - - - - - ((1.18 1.18))$

由公式(1.18)，可以通过一定偏移距h的g_c，直接换算g_s。According to formula (1.18), g _s can be directly converted by g _c at a certain offset distance h.

时间域多波AVA道集的抽取需要得到时间域的速度谱与各向异性参数谱，所以需要进行深时转换。根据公式(1.11)、(1.12)，Z0向T0转换时，需要用到P波的平均速度v_pa，且The extraction of multi-wave AVA gathers in the time domain needs to obtain the velocity spectrum and anisotropy parameter spectrum in the time domain, so deep-time conversion is required. According to formulas (1.11) and (1.12), when Z0 is converted to T0, the average velocity v _pa of the P wave needs to be used, and

${T T}_{00} = = \frac{22 {Z Z}_{00}}{{v v}_{Pa Pa}} . . - - - - - - ((1.19 1.19))$

当偏移距较小时v_Pm＝v_Pa，且各向异性参数对时距曲线形态特征的影响较小。当偏移距较大时v_Pm更接近均方根速度，且各向异性参数对时距曲线形态特征的影响较大。所以进行速度谱与各向异性参数的深时转换时，应该通过小偏移距的共成像点道集分析P、S波的偏移速度，并用来进行深时转换，用大偏移距的共成像点道集分析各向异性参数。When the offset is small v _Pm = v _Pa , and the anisotropy parameter has little influence on the shape characteristics of the time-distance curve. When the offset is large v _Pm is closer to the root mean square velocity, and the anisotropy parameter has a greater influence on the shape characteristics of the time-distance curve. Therefore, when performing deep-time conversion of velocity spectrum and anisotropy parameters, the migration velocity of P and S waves should be analyzed through the common imaging point gather with small offset, and used for deep-time conversion. Common image point gather analysis anisotropy parameters.

时间域形成多波AVA道集的过程与深度域共成像点道集抽取的过程类似，区别在于在层状介质假设下，采用直射线各向异性射线追踪可以确定等效偏移距h_e与入射角θ的关系为公式(1.20)，如下所示：The process of forming a multi-wave AVA gather in the time domain is similar to the process of extracting a common imaging point gather in the depth domain. The difference is that under the assumption of a layered medium, the equivalent offset h _e and The incident angle θ is related by Equation (1.20) as follows:

$θ θ = = arctan arctan \frac{{h h}_{e e}}{{z z}_{00}} . . - - - - - - ((1.20 1.20))$

将公式(1.6)带入公式(1.20)，得到CSP道集转换为AVA道集的解析公式(1.21)，如下所示：Substituting formula (1.6) into formula (1.20), the analytical formula (1.21) for converting CSP gathers to AVA gathers is obtained, as follows:

$θ θ = = {[[\frac{\frac{{v v}_{m m}^{22} {t t}^{22}}{44 {z z}_{00}^{22}} - - 11}{11 - - \frac{{v v}_{m m}^{22} {t t}^{22} {g g}_{e e}}{44}}]]}^{\frac{11}{22}} . . - - - - - - ((1.21 1.21))$

以上，大略说明了本发明之实施例所需要运用到的相关公式，以下将提供对应的实施例来进行说明。根据本发明的实施例，提供了一种转换波各向异性AVA道集抽取方法的方法。并且，本发明的实施例可应用于倾斜地层模型。Above, the relevant formulas that need to be used in the embodiments of the present invention are roughly described, and the corresponding embodiments will be provided below for illustration. According to an embodiment of the present invention, a method of converting a wave anisotropic AVA gather extraction method is provided. Also, embodiments of the present invention are applicable to inclined formation models.

图2是根据本发明实施例的转换波道集抽取方法的流程图，如图2所示，该方法包括：Fig. 2 is a flowchart of a method for extracting converted channel sets according to an embodiment of the present invention. As shown in Fig. 2, the method includes:

步骤S202，对PP波进行保幅预处理。其中，所述保幅预处理例如为矢量去噪，反褶积，振幅补偿，静校正等。Step S202, perform amplitude-preserving preprocessing on the PP wave. Wherein, the amplitude-preserving preprocessing includes, for example, vector denoising, deconvolution, amplitude compensation, static correction, and the like.

步骤S204，设置深度域偏移网格，根据一演算法并选定第一偏移距数据，以通过P波常速度偏移，得到所述PP波的深度域的共成像点道集。进一步来说，所述算法例如为前述公式(1.4)～(1.6)，且将PP波的各向异性参数g_P置为0。Step S204, setting the depth domain migration grid, and selecting the first offset data according to an algorithm, so as to obtain the common imaging point gather of the depth domain of the PP wave through P wave constant velocity migration. Further, the algorithm is, for example, the aforementioned formulas (1.4) to (1.6), and the anisotropy parameter g _P of the PP wave is set to 0.

步骤S206，计算共成像点道集的r谱，得到更新的P波均方根速度。进一步来说，此步骤基于公式(1.15)，计算PP波共成像点道集的r谱，得到更新的P波均方根速度v_pm。Step S206, calculating the r-spectrum of the common imaging point gather to obtain the updated RMS velocity of the P wave. Further, this step is based on the formula (1.15) to calculate the r-spectrum of the PP-wave common imaging point gather, and obtain the updated P-wave RMS velocity v _pm .

步骤S208，将所述P波常速度替换成所述更新后的所述P波均方根速度v_pm，并叠代步骤S204、S206、S208，直至所述r谱的峰值点完全收敛于零为止。Step S208, replacing the P-wave constant velocity with the updated P-wave root-mean-square velocity v _pm , and iterating steps S204, S206, and S208 until the peak point of the r-spectrum completely converges to zero until.

步骤S210，选定第二偏移距数据，通过所述P波常速度偏移，得到所述PP波的深度域的所述共成像点道集，其中所述第二偏移距数据大于所述第一偏移距数据。Step S210, selecting the second offset data, and obtaining the common imaging point gather in the depth domain of the PP wave through the P-wave constant velocity migration, wherein the second offset data is larger than the set The first offset data.

步骤S212，计算共成像点道集的g谱，得到更新的PP波的各向异性参数。进一步来说，此步骤基于公式(1.15)，且将r置为0，以计算共成像点道集的g谱，得到更新的PP波的各向异性参数。Step S212, calculating the g-spectrum of the common imaging point gather to obtain updated anisotropy parameters of the PP wave. Furthermore, this step is based on formula (1.15), and r is set to 0 to calculate the g-spectrum of the common imaging point gather, and obtain the updated anisotropy parameters of the PP wave.

步骤S214，根据所述更新后的P波均方根速度v_pm，计算深时对应关系，将更新后的所述P波均方根速度v_pm、更新后的所述P波的各向异性参数g_P转换到时间域。进一步来说，此步骤基于公式(1.19)，计算深时对应关系，将更新后的所述P波均方根速度v_pm、更新后的所述P波的各向异性参数g_P转换到时间域。Step S214, according to the updated P wave root mean square velocity v _pm , calculate the deep-time correspondence relationship, the updated P wave root mean square velocity v _pm , the updated P wave anisotropy The parameter g _P converts to the time domain. Further, this step is based on the formula (1.19), calculates the deep-time correspondence, and converts the updated root mean square velocity v _pm of the P wave and the updated anisotropy parameter g _P of the P wave to time area.

步骤S216，抽取PP波的转换波道集。进一步来说，此步骤基于公式(1.21)，抽取PP波的转换波道集，且所述转换波道集例如为AVA道集。Step S216, extracting converted channel sets of PP waves. Furthermore, this step is based on the formula (1.21), extracting the converted channel set of PP waves, and the converted channel set is, for example, an AVA gather.

图3是根据本发明另一实施例的转换波道集抽取方法的流程图，如图3所示，该方法包括：Fig. 3 is a flowchart of a method for extracting converted channel sets according to another embodiment of the present invention. As shown in Fig. 3, the method includes:

步骤S302，对PS波进行保幅预处理。其中，所述保幅预处理例如为矢量去噪，反褶积，振幅补偿，静校正等。Step S302, performing amplitude-preserving preprocessing on the PS wave. Wherein, the amplitude-preserving preprocessing includes, for example, vector denoising, deconvolution, amplitude compensation, static correction, and the like.

步骤S304，设置深度域偏移网格公式，根据一演算法并选定第一移距数据，用PP波处理得到的P波均方根速度v_pm以及S波常速度偏移，得到所述PS波的深度域的共成像点道集。进一步来说，所述算法例如为前述公式(1.4)～(1.6)，且将PS波的各向异性参数g_S置为0。Step S304, setting the depth domain migration grid formula, according to an algorithm and selecting the first displacement data, using the P wave root mean square velocity v _pm and S wave constant velocity migration obtained by PP wave processing, to obtain the described Common image point gathers of PS waves in the depth domain. Further, the algorithm is, for example, the aforementioned formulas (1.4) to (1.6), and the anisotropy parameter g _S of the PS wave is set to 0.

步骤S306，计算所述PS波的共成像点道集的r谱，得到更新的S波均方根速度。进一步来说，此步骤先基于公式(1.15)，得到均方根速度v_Cm，再根据公式(1.9)、(1.10)换算，得到更新的S波均方根速度v_Sm。Step S306, calculating the r-spectrum of the common imaging point gather of the PS wave to obtain the updated root mean square velocity of the S wave. Further speaking, this step first obtains the root mean square velocity v _Cm based on formula (1.15), and then converts according to formulas (1.9) and (1.10) to obtain an updated S wave root mean square velocity v _Sm .

步骤S308，将所述S波常速度替换成更新后的所述S波均方根速度，并叠代步驟S304、S306、S308，直至r谱的峰值点完全收敛于零为止。Step S308, replacing the S-wave constant velocity with the updated S-wave root-mean-square velocity, and iterating steps S304, S306, and S308 until the peak point of the r-spectrum completely converges to zero.

步骤S310，选定第二偏移距数据，通过更新后的所述P波的各向异性参数g_P，消除下行所述P波旅行时的各向异性，偏移得到所述PS波的深度域的共成像点道集，其中所述第二偏移距数据大于所述第一移距数据。Step S310, select the second offset data, use the updated anisotropy parameter g _P of the P wave to eliminate the anisotropy of the travel time of the downlink P wave, and offset to obtain the depth of the PS wave A common imaging point gather of the domain, wherein the second offset data is greater than the first offset data.

步骤S312，计算所述PS波的所述共成像点道集的g谱，得到更新的所述PS波的各向异性参数。进一步来说，此步骤先基于公式(1.17)，且将r置为0，以计算PS波的共成像点道集的g谱，得到更新的各向异性参数g_C，再根据公式(1.18)换算，得到PS波的各向异性参数g_S。Step S312, calculating the g-spectrum of the common imaging point gather of the PS wave to obtain updated anisotropy parameters of the PS wave. Furthermore, this step is based on the formula (1.17), and r is set to 0 to calculate the g-spectrum of the common imaging point gather of the PS wave, and obtain the updated anisotropy parameter g _C , and then according to the formula (1.18) In conversion, the anisotropy parameter g _S of the PS wave is obtained.

步骤S314，根据PP波深时对应关系，将更新后的所述S波均方根速度v_Sm、更新后的所述PS波的各向异性参数g_S转换到时间域。进一步来说，此步骤基于公式(1.19)，根据PP波深时对应关系，将更新后的所述S波均方根速度v_Sm、更新后的所述PS波的各向异性参数g_S转换到时间域。Step S314 , according to the PP-wave depth-time correspondence, the updated root-mean-square velocity v _Sm of the S-wave and the updated anisotropy parameter g _S of the PS-wave are converted into the time domain. Further, this step is based on formula (1.19), and according to the corresponding relationship between PP wave depth and time, the updated root mean square velocity v _Sm of the S wave and the updated anisotropy parameter g _S of the PS wave are transformed into to the time domain.

步骤S316，抽取PS波的转换波道集。进一步来说，基于公式(1.21)，抽取PS波的转换波道集，且所述转换波道集例如为AVA道集。Step S316, extracting the converted channel set of the PS wave. Further, based on the formula (1.21), the converted channel set of the PS wave is extracted, and the converted channel set is, for example, an AVA gather.

图4是根据本发明实施例的最终抽取的PP波的AVA道集的示意圖。图5是根据本发明实施例的最终抽取的PS波的AVA道集的示意图。如图4及5所示，可见通过叠前时间偏移，PP波及PS波两者道集在反射时间上完全对应，避免了PS波压缩过程中的波形畸变，使AVA道集抽取方法精度较佳。Fig. 4 is a schematic diagram of an AVA gather of finally extracted PP waves according to an embodiment of the present invention. Fig. 5 is a schematic diagram of an AVA gather of finally extracted PS waves according to an embodiment of the present invention. As shown in Figures 4 and 5, it can be seen that through pre-stack time migration, the PP wave and PS wave gathers are completely corresponding in reflection time, which avoids the waveform distortion in the process of PS wave compression, and makes the AVA gather extraction method more accurate. good.

综上所述，根据本发明的技术方案，通过深度域利用P波与S波的偏移速度抽取CSP道集，基于剩余曲率分析方法更新偏移速度与各向异性参数，并根据换算的成像深度实现PP波与PS波的层位匹配；将深度域分析得到的P波、S波偏移速度、各向异性参数换算到PP波T0时间域，通过叠前偏移与各向异性射线追踪的方法得到层位完全匹配的PP波与PS波AVA道集，使AVA道集抽取方法精度较佳。In summary, according to the technical solution of the present invention, the CSP gathers are extracted by using the migration velocity of P-wave and S-wave in the depth domain, and the migration velocity and anisotropy parameters are updated based on the residual curvature analysis method, and according to the converted imaging Realize the layer matching between PP wave and PS wave in depth; convert the P wave, S wave migration velocity and anisotropy parameters obtained from the depth domain analysis to the PP wave T0 time domain, through prestack migration and anisotropic ray tracing The method obtained the PP wave and PS wave AVA gathers with completely matching horizons, so that the accuracy of AVA gather extraction method is better.

以上所述仅为本发明的实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的权利要求范围之内。The above description is only an embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A converted wave anisotropy amplitude change gather extraction method with incident angle, is characterized in that, comprises:

1) Perform amplitude-preserving preprocessing on the PP wave;

2) Setting the migration grid in the depth domain, and selecting the first offset data according to an algorithm, so as to obtain the common imaging point gather of the depth domain of the PP wave through P wave constant velocity migration;

3) Calculating the r-spectrum of the common imaging point gather to obtain an updated root-mean-square velocity of the P-wave;

4) replacing the P-wave constant velocity with the updated P-wave root-mean-square velocity, and iterating steps 2), 3), and 4), until the peak point of the r-spectrum completely converges to zero;

5) Select the second offset data, and obtain the common imaging point gather in the depth domain of the PP wave through the P-wave constant velocity migration, wherein the second offset data is greater than the first offset data;

6) Calculating the g-spectrum of the common imaging point gather to obtain the updated anisotropy parameter of the PP wave;

7) According to the updated P-wave RMS velocity, calculate the deep-time correspondence, and convert the updated P-wave RMS velocity and the updated P-wave anisotropy parameter into the time domain ;

8) Extracting the converted channel set of the PP wave.

2. The method according to claim 1, wherein the algorithm comprises the following formula:

t = {[\frac{z^{2} + d_{the s}^{2}}{v_{d}^{2} (1 + g_{the s} d_{the s}^{2})}]}^{\frac{1}{2}} + {[\frac{z^{2} + d_{r}^{2}}{v_{u}^{2} (1 + g_{r} d_{r}^{2})}]}^{\frac{1}{2}}; t_{e} = {[\frac{z^{2} + h_{e}^{2}}{v_{m}^{2} (1 + g_{e} h_{e}^{2})}]}^{\frac{1}{2}};

2t _e = t; And set the anisotropy parameter of the PP wave to 0, wherein t is the total travel time of the seismic wave, te _is the travel time of the seismic wave between the equivalent offset point and the scattering point, and he _is the distance between the scattering point and the scattering point The distance between equivalent offset points.

3. method according to claim 1, is characterized in that, the r spectrum of described calculation described common imaging point gather, obtains the step of the P wave root-mean-square velocity of renewal comprising:

formula based The r-spectrum of the common imaging point gather is calculated to obtain the updated RMS velocity of the P wave.

4. method according to claim 1, it is characterized in that, described computing the g spectrum of described common imaging point gather, the step that obtains the anisotropy parameter of the PP wave of updating comprises:

formula based The g-spectrum of the common imaging point gather is calculated to obtain the updated anisotropy parameters of the PP wave.

5. The method according to claim 1, characterized in that, according to the updated P-wave root-mean-square velocity, the corresponding relationship is calculated in depth, and the updated P-wave root-mean-square velocity, updated The steps after converting the anisotropy parameters of the P wave to the time domain include:

formula based Calculating the deep-time correspondence, converting the updated root-mean-square velocity of the P-wave and the updated anisotropy parameter of the P-wave to the time domain, where v _pa is the average velocity of the P-wave.

6. The method according to claim 1, wherein the step of extracting the converted wave gather of the PP wave comprises:

formula based The converted channel set of the PP wave is extracted, where θ is the incident angle.

7. A converted wave anisotropy amplitude change gather extraction method with incident angle, characterized in that it includes:

1) Perform amplitude-preserving preprocessing on the PS wave;

2) Set the migration grid formula in the depth domain, according to an algorithm and select the first displacement data, use the P wave root mean square velocity obtained by PP wave processing and the S wave constant velocity migration to obtain the PS wave Common image point gathers in the depth domain;

3) calculating the r-spectrum of the common imaging point gather of the PS wave to obtain the updated root mean square velocity of the S wave;

4) The S-wave constant velocity is replaced with the updated S-wave RMS velocity, and steps 2), 3), and 4) are iterated until the peak point of the r spectrum converges to zero completely;

5) Select the second offset data, and eliminate the anisotropy of the downlink travel time of the P wave through the updated anisotropy parameter of the P wave, and migrate to obtain the common value of the depth domain of the PS wave. an imaging point gather, wherein the second offset data is greater than the first offset data;

6) Calculating the g-spectrum of the common imaging point gather of the PS wave to obtain an updated anisotropy parameter of the PS wave;

7) according to the corresponding relationship between PP wave depth and time, the updated root mean square velocity of the S wave and the updated anisotropy parameter of the PS wave are converted to the time domain;

8) Extracting the converted channel set of the PS wave.

8. The method according to claim 7, wherein the algorithm comprises the following formula:

t = {[\frac{z^{2} + d_{the s}^{2}}{v_{d}^{2} (1 + g_{the s} d_{the s}^{2})}]}^{\frac{1}{2}} + {[\frac{z^{2} + d_{r}^{2}}{v_{u}^{2} (1 + g_{r} d_{r}^{2})}]}^{\frac{1}{2}}; t_{e} = {[\frac{z^{2} + h_{e}^{2}}{v_{m}^{2} (1 + g_{e} h_{e}^{2})}]}^{\frac{1}{2}};

9. method according to claim 7, it is characterized in that, the r spectrum of the co-imaging point gather of described calculation described PS wave, the step of the S wave root-mean-square velocity that obtains updating comprises:

formula based Calculate the r-spectrum of the common imaging point gather of the PS wave to obtain the root mean square velocity, and then according to the formula Conversion, get the updated root mean square velocity of S wave, where v _Pm is the root mean square velocity of P wave.

10. The method according to claim 7, wherein the g spectrum of the common imaging point gather of the PS wave is calculated, and the step of obtaining the anisotropy parameter of the PS wave updated comprises:

formula based And set r to 0, calculate the g spectrum of the common imaging point gather of the PS wave, obtain the updated anisotropy parameter, and then according to the formula Conversion, the updated PS wave anisotropy parameters are obtained, where g _c and g _s are anisotropy parameters, v _Pm is the root mean square velocity of the P wave, and v _P is the root mean square velocity of the P wave.

11. The method according to claim 7, characterized in that, according to the PP wave depth time correspondence, the updated S-wave RMS velocity, the updated anisotropy parameter of the PS wave The steps to convert to the time domain include:

12. The method according to claim 7, wherein the step of extracting the converted wave gather of the PS wave comprises:

formula based The converted channel set of the PS wave is extracted, where θ is the incident angle.