Search

CN-122018003-A - First-arrival refraction area linear interference suppression method, product, medium and equipment

CN122018003ACN 122018003 ACN122018003 ACN 122018003ACN-122018003-A

Abstract

The invention discloses a first-arrival refraction area linear interference suppression method, a product, a medium and equipment, belonging to the technical field of seismic data processing. The method comprises the steps of designing different parameters aiming at the inconsistent linear characteristics of different frequency band ranges, decomposing seismic data into subsets of different scales and directions by utilizing the multi-scale and multi-directional characterization capability of curvelet transformation, and realizing accurate wave field separation in each curvelet domain through radon transformation so as to eliminate refractive interference with stronger energy of a first-arrival refractive region and recover effective reflection signals in an offset range. The invention can precisely suppress first arrival refraction interference, recover effective signals and improve the seismic imaging quality.

Inventors

  • TANG JING

Assignees

  • 唐晶

Dates

Publication Date
20260512
Application Date
20260226

Claims (10)

  1. 1. A method for suppressing linear interference in a first-arrival refraction zone, the method comprising: Utilizing multi-scale and multi-directional characterization capability of curvelet transformation to decompose the seismic data into subsets of different scales and directions, and realizing accurate wave field separation in each curvelet domain by Lato transformation so as to eliminate refractive interference with stronger energy of a first-arrival refractive region and recover effective reflected signals in an offset range.
  2. 2. The first-arrival refractive zone linear interference suppression method according to claim 1, characterized in that the method comprises the steps of: s1, preprocessing seismic data and finely dividing frequency bands; S2, carrying out differential parameter design aiming at different frequency bands; s3, performing curved wave forward conversion on the seismic data according to the designed parameters, converting t-x domain data into a curved wave domain and decomposing the curved wave domain data into subsets with different scales and directions; S4, traversing and applying Ladong transformation parameters of corresponding frequency bands one by one in each curvelet domain according to the designed parameters, and mapping the linear interference of the curvelet domain into focusing energy points of the Ladong domain; realizing linear Ladong forward conversion in a discretization integral form, solving the discomfort of discrete Ladong conversion through least square regularization, finally obtaining Ladong domain data corresponding to each curved wave domain subset, and realizing accurate wave field separation through Ladong conversion; S5, converting the Ladong domain data back to Qu Boji number domains by adopting a conjugate transpose operator of Ladong forward conversion, and recovering a curvelet coefficient matrix of each scale-direction, wherein only effective wave coefficients and a small amount of residual noise coefficients are reserved in the matrix; S6, performing inverse curvelet transformation on the restored curvelet coefficient matrix.
  3. 3. The first-arrival refraction zone linear interference suppression method according to claim 2, wherein radon domain adaptive threshold filtering is performed between steps S4 and S5: and carrying out energy statistics on the data after processing, and readjusting the threshold value to ensure the interference suppression effect if the energy rejection rate of a plurality of interference waves is less than the judgment threshold value.
  4. 4. The first-arrival refraction zone linear interference suppression method according to claim 2, wherein the content of step S3 comprises: 2D FFT conversion is carried out to obtain frequency-wave number domain data; non-uniform resampling is carried out according to the curvelet scale parameter J; Weighting with a Gaussian window function to realize scale or direction localization; The localized concentrated energy is wrapped around the origin; 2D IFFT conversion is carried out to obtain a curvelet coefficient matrix; And finally outputting the curvelet coefficient matrixes with different scales and directions corresponding to the low, medium and high frequency bands.
  5. 5. The first-arrival refraction zone linear interference suppression method according to claim 2, wherein the content of step S2 comprises: The method comprises the steps of adopting a second generation of Wrapping rapid algorithm to design a scale number J, a direction number L, a window function bandwidth coefficient alpha, a low-frequency band coarse scale, a low-direction resolution, a high-frequency band fine scale and a high-direction resolution so as to adapt to the crushing degree of interference linear characteristics; And the radon transformation parameters are linear radon transformation, the core is designed to be a ray parameter p and a regularization parameter lambda, the ray parameter p is inversely related to the visual speed, and the regularization parameter lambda is positively related to the interference energy so as to solve the discomfort of the radon transformation and improve the focusing effect.
  6. 6. The first-arrival refraction zone linear interference suppression method according to claim 5, wherein the content of step S2 further comprises: And the threshold filtering parameters are that three types of hard threshold, semi-soft threshold and soft threshold are designed according to the energy difference between interference and effective wave, different threshold sizes and coefficients are matched, and the interference rejection thoroughness and the effective signal amplitude preservation performance are considered.
  7. 7. The first-arrival refraction zone linear interference suppression method according to claim 2, wherein the content of step S6 comprises: Firstly, carrying out 2D FFT conversion on a denoised curvelet coefficient matrix, recovering the original position of a frequency wave domain through inverse Wrapping operation, carrying out conjugate multiplication on the original position and a window function to finish scale or direction inverse localization, and finally merging all scale-direction data blocks, converting the data blocks back to a t-x domain through 2D IFFT conversion to obtain single shot seismic data with first arrival refraction interference removed.
  8. 8. A computer program product comprising a computer program, characterized in that the computer program when executed by a processor realizes the steps of the first-arrival refraction zone linear interference suppression method according to claims 1-7.
  9. 9. A computer readable storage medium having stored thereon a computer program, characterized in that the computer program when executed by a processor realizes the steps of the first-arrival refractive zone linear interference suppression method according to claims 1-7.
  10. 10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor executes the computer program to implement the steps of the first-arrival refraction zone linear interference suppression method of claims 1-7.

Description

First-arrival refraction area linear interference suppression method, product, medium and equipment Technical Field The invention belongs to the technical field of seismic data processing, and particularly relates to a first-arrival refraction area linear interference suppression method, a product, a medium and equipment. Background In streamer seismic acquisition, the water depth has a greater impact on the linear time-distance curve of the first arrival refracted wave. According to snell's law, the horizontal distance required for a seismic wave to strike the sea floor at a critical angle and produce a refracted wave is short. Thus, refracted waves from the high-speed substrate can be received at a receiver that is very close to the source. Because of the depth of water, the travel time difference between the refracted wave path and the direct wave path is small, and if the formation speed is far greater than the water speed, the refracted wave arrives earlier than the direct wave. Thus, any reflected wave from the same interface or a shallower interface must travel later than the refracted wave. On the time-distance curve, the travel time of the refraction wave and the offset have good linear relation. The first-arrival region refractive wave is dominant and is rapidly occupied by the refractive wave, so that a clear and stable linear region is formed. In addition, because the refracted wave propagates along the high-speed layer top interface, a large amount of energy can be generally gathered, and particularly the refracted wave generated on the top surface of the high-speed substrate has very strong energy. While the energy of the reflected wave decays with the square of the propagation distance and a portion of the energy is transmitted at the interface and is therefore relatively weak. FIG. 1 shows a forward single shot, and it can be seen that the first arrival refraction interference range is almost 50% of the single shot range, and the offset range below 4s is almost submerged in the refraction linear interference, in the range of 7000 meters to 15000 meters of cable length. The shallow water area towing cable collects seismic data, the first-arrival refraction area is represented as a triangular area, interference wave energy is strong, and a good linear rule is presented. Such linear disturbances are characterized by low velocity on the original mono-cannon. In a triangle area where first-arrival refraction interference develops, based on the visual speed difference between linear interference and effective signals, technologies such as Radon transformation nonlinearity, FK nonlinearity, T-X domain dip angle filtering and the like are adopted to realize suppression of linear noise. However, due to the fact that interference waves in the first-arrival refraction area are complex, after the technology is applied, the phenomenon that pressing is not thorough enough or effective signals are lost in the pressing process often occurs. Therefore, a new first-arrival refractive zone linear interference suppression method is needed. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the related art described above to some extent. Therefore, the invention aims to provide a first-arrival refraction area linear interference suppression method, a product, a medium and equipment, which can accurately suppress first-arrival refraction interference, recover effective signals and improve seismic imaging quality. In order to solve the technical problems, the invention is realized as follows: The embodiment of the invention provides a first-arrival refraction area linear interference suppression method, which comprises the following steps: Utilizing multi-scale and multi-directional characterization capability of curvelet transformation to decompose the seismic data into subsets of different scales and directions, and realizing accurate wave field separation in each curvelet domain by Lato transformation so as to eliminate refractive interference with stronger energy of a first-arrival refractive region and recover effective reflected signals in an offset range. In addition, the first-arrival refraction area linear interference suppression method according to the invention can also have the following additional technical characteristics: In some of these embodiments, the steps of the method include: s1, preprocessing seismic data and finely dividing frequency bands; S2, carrying out differential parameter design aiming at different frequency bands; s3, performing curved wave forward conversion on the seismic data according to the designed parameters, converting t-x domain data into a curved wave domain and decomposing the curved wave domain data into subsets with different scales and directions; S4, traversing and applying Ladong transformation parameters of corresponding frequency bands one by one in each curvelet domain according to the designed parameters, and