• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention discloses an anisotropic seismic imaging method comprising the steps in Figure 1. According to the anisotropic seismic imaging method, the ratio of contribution of effective signals to the final imaging result is increased, and the calculation accuracy of the anisotropic migration method is increased. improved.
    公开号:BE1027342B1
    申请号:E20195787
    申请日:2019-11-13
    公开日:2021-01-07
    发明作者:Hui Sun
    申请人:Univ Southwest Jiaotong；
    IPC主号:
    专利说明:

    METHOD FOR ANISOTROPIC SEISMIC IMAGING
    TECHNICAL DOMAIN The present invention belongs to the field of seismic migration imaging and relates in particular to a method for anisotropic seismic imaging.
    BACKGROUND In a common migration imaging method, a target geologic body is considered an isotropic medium, while anisotropy is common in geologic bodies. When processing long offset distance, wide azimuth seismic data, the problems that migration energy cannot be better directed and the migration noise is increased, which is easily caused by anisotropy, is not taken into account. Due to these problems, the accuracy of seismic imaging can decrease and certain problems can arise for oil and gas research.
    The Kirchhoff Type Dynamic Focusing Beam Migration was disclosed in a doctoral thesis from Jilin University in 2017. In the thesis, an anisotropic Kirchhoff method of ray beam migration type is introduced, and anisotropic beam detection is introduced in the anisotropic ray beam migration by the anisotropic body migration method. to process. In addition, an imaging test is performed on an anisotropic Hess model by the anisotropic Kirchhoff ray beam migration method, and good migration results are obtained.
    In 'Application of Pseudo-Acoustic Prestack Reverse-Time Migration and Imaging Conditions of Anisotropic Medium' written by Ayizemuguli Ruze and others in the fourth issue of 2017 of Geophysical and Geochemical Exploration Calculation Technology, a method was disclosed in which anisotropic reverse time migration imaging was introduced , an acoustic wave equation of a VTI (variable timing injection) media was studied, optimized normalized joint correlation imaging conditions were applied, the method was controlled by the Hess model for anisotropy, and a good imaging effect was achieved.
    From the above examples, it can be seen that anisotropic data bodies can be mapped to some extent by a conventional imaging method, but that imaging accuracy is still capable of improvement.
    SUMMARY To improve the computation accuracy of an anisotropic seismic imaging method, the present invention provides an anisotropic seismic imaging method.
    The anisotropic seismic imaging method comprises the following steps of step 1, reading into an anisotropic parameter model, a P-wave velocity model and a parameter file; step 2, performing anisotropic beam detection on a shot point by a Runge-Kutta method in different directions, and calculating the information on a beam of beam corresponding to each beam; step 3, dividing single shot seismic files into a plurality of data bodies with one window as a unit; step 4, calculating the partial derivative of the data bodies in the windows by time and the partial derivative of the data bodies by space, and performing local plane wave decomposition on the seismic files in the windows; step 5, performing anisotropic beam search on the window center in different directions, and calculating the information on a beam of beam corresponding to each ray; step 6, performing imaging computation on all ray beam pairs in the shot point and window center by a new imaging formula with an added weighting function, and step 7, merging imaging results of all ray beam pairs, so as to obtain a final migration imaging result.
    The anisotropic parameter model in step 1 further includes an anisotropic parameter model and an anisotropic parameter model; the parameter file includes the dimensions of a grid, the initial beam width, the number of seismic channels, channel spacing, the number of sample points in each channel, and minimum and maximum frequencies.
    Furthermore, the beam tracing equations in step 2 are the following: dx; Dr Aj P18 781 dp; 1 Od dt TS 2 ÖX; DaDPi8j8xr where x, represents the spatial position of discrete points; Pi + Pan and Pp; Stand for the inertial component; T represents the seismic movement time; a, is calculated by the formula aq, = CGu / P1 €, represents the elastic modulus, and p represents the density; 8; and 2, represent feature vector components, and O is a symbol for a partially derivative; Information about matching beams is obtained by a beam width calculation formula after knowing the central beam information, the beam beam width calculation formula W is shown as follows: 5 w = 240 7 V, where V, is the velocity value at the shot point and © represents the integral of a velocity-based beam path; further, in step 3, the center distance of the windows is usually selected from 200 m to 500 m and the persistence length of the windows is 1.5 times the initial beam width. further, in step 6, the weighting added imaging formula is as follows: 1.0) = F [dp, [dp, AW, D, (L, P'.T ") 7 where /, represents the imaging value of a single shot; x represents the position of an imaging point; pP, and pP, respectively, represent inertial parameters of beams fired from the firing point and the window center; A represents the amplitude; D represents the local plane wave decomposition result; L represents the position of the window center r and 7 'represent the inertia and motion parameters for local slope superposition, the expression of the weighting coefficient W, in the imaging formula is shown as follows: 2 W.- ape VW) ”Danen WEG) | A WEG) | where YW represents the seismic records, WY, and YW, respectively, represent the partial derivatives of the seismic records by time and space, W represents a series of points meeting the requirements of inertia and movement time, and l ,; vo or seismic movement time.
    Compared to the prior art, the anisotropic imaging method has the beneficial effects of adding a new weighting coefficient to the imaging formula, such that the contribution ratio of effective signals to a final imaging result is increased, and the anti-interference and anti-interference ability. the accuracy of the calculation of a Kirchhoff anisotropic method of the beam migration type can be improved.
    BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a Kirchhoff anisotropic process of the beam migration type; Fig 2 is a flow distribution diagram of a P wave velocity value of a Hess model;
    Fig 3 is a flow distribution diagram of an anisotropic parameter 6 of the Hess model; Fig 4 is a flow distribution diagram of an anisotropic parameter s of the Hess model; FIG. 5 is an enlarged view of a local imaging result of an original Kirchhoff anisotropic method of the Hess model beam migration type; FIG. 6 is an enlarged view of a local imaging result of a new Kirchhoff anisotropic method of the beam migration type of the Hess model.
    DETAILED DESCRIPTION The present invention is further described in detail in conjunction with drawings and specific embodiments.
    FIG. 1 shows a flow diagram of an anisotropic seismic imaging method specifically comprising the following steps:
    1. reading in an anisotropic parameter model, a P wave velocity model and a parameter file, wherein the anisotropic parameter model comprises an anisotropic T parameter model and an anisotropic & parameter model; the parameter file includes the dimensions of a grid, the initial beam width, the number of seismic channels, channel spacing, the number of sample points in each channel, and minimum and maximum frequencies;
    2. firing beams from a shot point in different directions, the angular range of the beams being -70 degrees to 70 degrees, and the angular distance A0 of the beams is usually selected as 2 degrees to 4 degrees; anisotropic kinematic beam tracing equations are solved by a Runge-Kutta method, and the comparison group is shown as follows: dx; Dr Aj P18 781 dp; 1 Ca EI UM; dT 2 0%, DnPiS j8r where x, represents the spatial position of discrete points; p; represents the inertial component; 7 represents the seismic movement time; 4, is calculated by the formula Gym = Cu / P + ©, represents the elastic modulus, and p represents the density; 8; and g, represents feature vector components; obtaining information about matching beams by a beam width calculation formula after knowing the central beam information, the beam beam width calculation formula W being shown as follows: Oo w = 2A0— V,
    where V, represents the velocity value at the shot point and © represents the integral of a jet path based on velocity;
    3.dividing single shot seismic files into a plurality of data bodies with a window as a unit, with the center distance of the windows usually selected from 200 m to 500 m and the persistence length of the windows 1.5 times the initial beam width is;
    4. calculating the partial derivative of the data bodies in the windows by time and the partial derivative of the data bodies by space, and performing local plane wave decomposition on the seismic files in the windows;
    5.performing anisotropic beam tracing on the window center point in different directions, and calculating the information of a ray beam corresponding to each ray, Step 5 being similar to Step 2 and Step 5 and Step 2 having the only difference that the positions of the coordinates of the shot point and the window center are different;
    6. performing imaging computation on all beam pairs in the shot point and the window center by a new imaging formula with an added weighting function, showing an imaging formula of Kirchhoff's original anisotropic method of ray beam migration type as follows: 1.00 => [dp , | dp, AD, (L, p'.T ") where /, represents the imaging value of a single shot, x represents the position of a pixel, Ps and P, respectively, represent inertial parameters of beams fired from the firing point and the window center; A stands for amplitude; D stands for local plane wave decomposition result; stands for position of window center; p 'and T' stands for inertial and moving time parameters for local slope superposition; original imaging formula TP allows data bodies from the domain obtained by the local plane wave decomposition, will have an effect on a final imaging result of equal weight and no difference as long as imaging conditions are met, but invalid 7-P data of the domain may be introduced in the steps of the local plane wave decomposition result due to problems such as a flattening effect, and the data has a negative effect on the def initial imaging result; In the present invention, a new weighting coefficient is added to the original imaging formula, such that the contribution ratio of effective signals to a final migration result is increased and the new imaging formula is shown as follows: 1.00 => [dp, | dp AW, D (L. p'7 ") where an expression of the weighting coefficient W, in the imaging formula is shown as follows: 2 W.- ape VW)” Nae WEE) | ne VG) where YW is the seismic files, WY, and YW, respectively, represent the partial derivatives of the seismic files by time and space, W represents a series of points that meet the requirements of inertia and movement time, and
    7. merging imaging results from all ray beam pairs to obtain a final migration imaging result.
    Simulation control: The scheme and beneficial effects of the present invention are controlled by an anisotropic Hess model. FIG. 2, FIG. 3 and FIG. 4 represent the distribution of a P-wave velocity value, the distribution of a parameter δ and the distribution of a parameter s of the anisotropic Hess model. The model has 3,617 grid points horizontally, and the grid spacing is 20 m; the model has 1,501 grid points in the length, and the grid spacing is 20 m.
    The data collection includes 720 shots, the shooting mode is one-sided shooting, the shooting distance is 100m, and the channel distance is 40m; and each channel includes 1,333 sample points and the sample interval is 6 ms.
    FIG. 5 is an original Kirchhoff anisotropic method of the beam migration type, and FIG. 6 is a migration result of the method of the present invention.
    From a contrast result diagram, it can be seen that the imaging result of the present invention has less migration noise, higher signal-to-noise ratio, and is more apparent in the geological structure shown.
    The method disclosed by the present invention is an important prestack depth migration method of an anisotropic medium; invalid data in local slope superposition is not specially processed according to the original imaging formula; a new weighting coefficient is added to the original imaging formula, so that the ratio of contribution of effective signals to the final imaging result is increased, and the calculation accuracy of the anisotropic migration method is improved.
    权利要求:
    Claims (2)
    [1]
    1. Method for anisotropic seismic imaging, characterized by comprising the following steps of step 1, reading in an anisotropic parameter model, a P-wave velocity model and a parameter file; step 2, performing anisotropic beam detection on a shot point by a Runge-Kutta method in different directions, and calculating the information on a beam of beam corresponding to each beam; step 3, dividing single shot seismic files into a plurality of data bodies with one window as a unit; step 4, calculating the partial derivative of the data bodies in the windows by time and the partial derivative of the data bodies by space, and performing local plane wave decomposition on the seismic files in the windows; step 5, performing anisotropic beam search on the window center in different directions, and calculating the information on a beam of beam corresponding to each ray; step 6, performing imaging computation on all ray beam pairs in the shot point and window center by a new imaging formula with an added weighting function, and step 7, merging imaging results of all ray beam pairs, so as to obtain a final migration imaging result.
    [2]
    Anisotropic seismic imaging method according to claim 1, characterized in that the imaging formula with an added weighting function in step 6 is herein that 1.00 => [dp, | dp AW, D (L. P'7 ") where /, represents the imaging value of a single shot; x represents the position of an imaging point; pP, and pP, respectively, represent inertial parameters of beams fired from the firing point and the window center; A represents the amplitude; D, the local plane wave decomposition result ; L represents the position of the window center point r and 7 'represents the inertial and motion parameters for local slope superposition; the expression of the weighting coefficient W, in the imaging formula, is shown as follows:
    W.-> new VW) | í Danen WEG) | A WAY) | where YW represents the seismic files, YW, and YW respectively represent the partial derivatives of the seismic files by time and space, W represents a series of points meeting the requirements of inertia and time of movement, x, represents the spatial position of discrete points, and l ,; represents the seismic movement time.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN105549081A|2016-01-29|2016-05-04|中国石油大学|Anisotropic medium common shot domain Gaussian beam migration imaging method|
    CN106291687A|2016-07-21|2017-01-04|中国地质科学院地质研究所|Anisotropy many ripples Gaussian beam pre-stack depth migration imaging method|
    NL2020152A|2017-11-06|2018-01-25|Univ Southwest Jiaotong|Kirchhoff Beam Migration Method Under Complex Topography|
    CN108363101A|2018-02-02|2018-08-03|西安石油大学|A kind of inclined shaft crosshole seismic Gaussian beam pre-stack depth migration imaging method|
    CN102495426B|2011-12-02|2014-10-22|北京中科联衡科技有限公司|Kirchhoff integral seismic imaging method|
    US9594176B1|2012-08-01|2017-03-14|Z Terra Inc.|Fast beam migration using plane-wave destructor beam forming|
    CN103984019B|2014-06-07|2017-01-11|吉林大学|Local relevant weighted earthquake beam synthesis method|
    US11041972B2|2017-06-14|2021-06-22|Pgs Geophysical As|Methods and systems to enhance resolution of seismic images|CN112630825A|2020-12-02|2021-04-09|中国海洋大学|Common offset domain Beam prestack time migration imaging method, system, medium and application|
    CN112904418B|2021-01-22|2021-08-17|西南交通大学|Self-adaptive ray encryption type kirchhoff type beam migration seismic wave imaging method|
    法律状态:
    2021-03-19| FG| Patent granted|Effective date: 20210107 |
    优先权:
    申请号 | 申请日 | 专利标题
    CN201910977970.XA|CN110780341B|2019-10-15|2019-10-15|Anisotropic seismic imaging method|
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