Applicatuon Research On The Loess Tableland Area Strong Lateral Shifting Tectonic Imaging Methods

In recent years, as the key to energy exploration in China from the eastern to thewestern region of the transfer, the in-depth application of seismic explorationtechnology research also from plains and hills to more complex mountain, gobi, desertand loess tableland area. Nowadays, the problem of imaging in complex area of studywidely up gradually, especially for static correction problem is serious on the loesstableland landscape area, the seismic imaging of complex structure are the focus ofthe study area for problem more experts and scholars.The signal-to-noise ratio of seismic data in Loess tableland area is relatively low,to a certain extent,it reflects the excitation condition change and the seriousness of theproblem of static correction, therefore, we want to make the final migration imagingeffect good, we must carefully analyze the original earthquake data, develop a reliableprocessing procedure, and choose the right key processing technology.This article is based on the edge of the ordos basin of the loess tableland areacoalfield seismic data as the foundation, the complex near surface conditions in thestudy area, belong to typical loess covered landscape, horizontal change drastically,surface structure and lithology to change; Underground structure is complex, manysteep inclined structure for large dip Angle, lateral changes and intense. Previousseismic processing result is post-stack time migration, the results interpreted as faultis over400meters, but through the drilling and geological outcrop geological datareveal validation, severe seismic interpretation results and the geological condition isfound not to conform, seismic migration imaging processing there is a big problem,not correctly reflect the real underground structure form. In view of this problem, thispaper to formulate the reasonable seismic data processing process, from the staticcorrection method, signal-noise separation and migration imaging technology to manyaspects, such as more in-depth and comprehensive analysis and research, to explore aset of specific success of form a complete set of processing technology, in order toopen the deadlock to coalfield seismic exploration in the area. From the principle and application effect of static correction methods wereanalyzed, the tomographic static correction is obtained to solve the problem of staticcorrection of the loess tableland area effect is better. Because of the refraction staticcorrection has significant limitations, there is only a relatively stable refractor, cancalculate more correct delay and refractor speed; In addition, it is must be knownsurface speed, to correctly converts delay when the refraction surface depth.Tomographic static correction in this paper uses a nonlinear tomography inversionand ray path nonlinearity, the velocity distribution is obtained by forward and inverseiteration method, can well solve the near surface complexity, early to fluctuations inthe correction of nonlinear static correction problems.In addition to the static correction problem is serious, time domain denoising willseriously, denoising approach incledes set by the rules of suppressing interference andsuppression of anomaly amplitude, suppressing random noise, residual staticcorrection before the surface consistency deconvolution technology unified seismicwavelet and phase, to improve data consistency and resolution. In surface consistentresidual static correction and prestack denoising quasi three-dimensional RNAprocessing after the multichannel predictive inverse plait technology to improve theinformation spectrum characteristics, further improve the data resolution.Based on the Kirchhoff integral migration imaging method, this method is reallythe surface deflection, choose a good offset datum is very important. By uniformdatum and floating datum on the stack and prestack time migration section contrast,for the loess tableland area migration homing, floating datum shift effect significantlybetter than the unity datum migration section.After identified the partial datum, the difficulty is to calculate the interval velocity.In prestack depth migration imaging process, to establish the initial velocity depthmodel, using the principle of tomographic imaging technique to modify velocity depthmodel, the change of velocity error can not be completed at a time, the speed isproperly required by the migration imaging to test. After repeated iterations, modifythe model, and ultimately get fine coal structure form. Through geological datavalidation, prestack depth migration results has a certain reliability, locate the finalinterpretation scheme, and summarizes a set of suitable for processing the data of theloess tableland area process and scheme, on the loess tableland area of coalfieldstructure imaging has important practical value, to achieve the purpose of the study.