The fine processing and interpretation technology of 3D seismic data can effectively utilize the continuously abundant exploration-production comparison information in coal mine production process and the latest data processing and interpretation technologies to dynamically analyze seismic prospecting data. That is, in the process of carrying out work by using existing seismic exploration results in coal mines, targeted data processing and interpretation measures shall be taken for specific problems to effectively improve the structural interpretation accuracy of mining areas and provide geological forecast for working face design and stoping.
1. Fine processing technology
For fine data processing, a targeted data processing process shall be formulated closely around geological tasks, characteristics of exploration areas and processing difficulties to achieve high resolution, high fidelity, high signal-to-noise ratio and high accuracy. Through the analysis and study of geological characteristics, original data and original seismic exploration report in the exploration area, it is determined that static correction, pre-stack denoising, metamorphic region data removal, deconvolution, pre-stack time migration and resolution improvement should be focused on under the premise of conventional processing.
(1) High-precision iterative static correction technology
a. Refraction statics; b. Tomographic statics; c. Fat-ray statics; d. Residual statics.
(2) Multi-domain and multi-method joint prestack denoising technology
a.Multi-domain joint denoising of shot point, geophone point and common offset range;
b.Joint denoising by frequency division, time division, slice and wavelet decomposition;
c.Joint de-noising with multi-processing system dominance method;
(3) Amplitude processing technology
a. Spherical diffusion amplitude compensation; b. Surface uniformity amplitude compensation; c. Amplitude absorption compensation.
(4) Fine processing technology of data in the metamorphosis area
a. Three-dimensional regularization technique; b. Five-dimensional interpolation technique; c. Fine excision technique.
(5) Pre-stack time migration technology
a. Fine calculation of prestack velocity; b. Ke Xihuofu prestack time migration technology.
(6) Resolution improvement technology
a. Pulse deconvolution; b. Surface uniform deconvolution; c. De-Q filtering; d. Wavelet reconstruction; e. Blue filtering; f. Spectral whitening.
Fig. 1 Comparison of Overlay, Post-stack Migration and Pre-stack Migration Methods
2. Fine interpretation technology
Fine tectonic interpretation is the basis of lithological interpretation and all other interpretations. High-resolution three-dimensional data volume must be provided to realize fine interpretation. A lot of practice shows that the application of coherent data volume is beneficial to fault interpretation, and ant body slice information can well show the discontinuity of information and play a good role in fine structure interpretation. Tectonic interpretation is developing from single traveltime information to multi-information comprehensive interpretation.
(1) Analysis of wave group characteristics and horizon interpretation
a. Synthetic seismogram production; b. Dynamic characteristics analysis of typical wave groups; c. Three-dimensional distribution of tectonic space. Analysis; a. well-seismic joint horizon calibration; b. interactive interpretation of horizons; c. multidirectional horizon correlation and closed tracking;
(2) Conventional fault interpretation
a. Structural pattern analysis; b. Interactive interpretation of fault breakpoints; c. Spatial combination of faults.
(3) Interpretation of coal seam scouring zone
(4) Interpretation of seismic attribute faults
a. Layer attribute analysis; b. Variance volume attributes; c. Spectral decomposition technique; d. Ant tracking.
(6) Drawing of plan
a. Drawing of isochron plan; b. Calculation of average velocity; c. Time-depth conversion; d. Drawing of structural plan.
Fig. 2 Joint Interpretation of Faults on Bedding Time Slice and Time Profile of Variance Body
3.Processing and Interpretation Quality Control
(1) Treatment quality control
In order to ensure the treatment quality of this project, in accordance with the requirements of ISO9001 quality management system certified by Xi'an Research Institute and engineering project management measures, the treatment design and process of this treatment item are strictly controlled to ensure the treatment quality.
a. Solidly and meticulously do all basic work on the basis of careful analysis of original data;
b. Do a good job in key processing links and key parameter testing;
c. According to the characteristics of the exploration area, adopt targeted treatment technology and formulate targeted treatment process;
d. Adopt amplitude-preserving and high-resolution processing ideas to provide high-quality and reliable processing results for geological interpretation.
Figure 3 Quality Control Chart of Well Control Deconvolution Step Size Parameters
(2) Quality control of data interpretation
In order to ensure the quality of interpretation results of the Project, during the interpretation process, the project team strictly controls the interpretation design, production process and service of the interpretation item to ensure the quality of geological results.
a.Artificial synthetic seismograms are made using well data to fine-tune the target horizon.
b. Interpretation of horizon and structure line by line;
d. Comprehensively apply seismic attribute interpretation technologies such as coherence, variance, spectral decomposition and multi-attribute fusion to improve the interpretation accuracy of faults and geological anomalies.
d. Interpret the main coal seam thickness and its variation trend by using inversion method.
e. Geophysical prospecting and geological experts shall carefully check and analyze the interpretation scheme during project operation to ensure that the Project is carried out scientifically and orderly.
