Local CMP stacking improvement technique for better traceability of separate reflection horizon

Abstract

Relevance. Today increasingly more objects of prospecting seismology belong to problem areas characterized by unfavorable surface conditions and complex geological situation. Acquiring of high-quality seismic images by processing in these cases is a part of priority directions of modern prospecting seismology. One of the way to overcome the problem of seismic horizon traceability worsening in hard conditions is optimized CMP stacking, considering the quality of input seismic data. Aim. This work is devoted to generation and examination of flexible universal technique of optimized stacking on the last stage of field or final processing of 2D/3D reflection seismic data for seismic horizon traceability improvement. Creating this technique assumed important condition of embodiment ability in existing software (including Russian). Methods. Illumination model building was performed for target horizon, located beneath the erosive cut for studying of complex geological objects influence on energy distribution in CMP gathers. Scattering superficial anomalies influence was estimated by means of 2D ray tracing and synthetic shot records generation on horizontally layered model sectionconsisting near surface ancient karst spot. Synthetic data with different kinds of noise and signal amplitude decay zone war generated to appreciate implementation potential of introducing technique. Stacked traces were obtained and evaluated on this data with different methods. The introduced technique was tested on real 2D seismic data too. Evaluation of results of different kinds of stacking was performed by sight and with quantitative (attribute) analysis. Results. Performed research showed insufficient efficiency convenience CMP stacking for complex seismic data. The advantages of existing CMP stacking improvement methods are obvious but there are drawbacks too: natural wave field dynamic violation, disability of local implementation, need of special software development. Offered technique of stacking optimization gives high flexibility and mobility in work and allow overcoming the aforementioned problems. Easy choice of trace range weighting criteria based on customer attribute set analysis gives wide opportunities of fine-tuning for this procedure, bringing in interpretation term of stack optimization process and making it more sensible in geological-geophysical relation. This technique need not new software development and testing, it could be embodied in existing seismic software suites, including Russian complexes.