| The static corrections are essential to data acquisition, data processing and interpretation for complex near-surface areas. There are various methods to deal with the statics correction problem in the complicated region, but each method is limited to certain static problem because of its assumptions and the scope of its applications. Complex area represents severely rugged topography, greatly heterogeneous of surface rock characteristics and strong lateral variations of thickness and velocity in low-velocity layer. Extremely complicated geological conditions results in many static correction methods either hard to adapt or limited, and rare software packages provide static correction functions. As a result, seismic data processors are often puzzling to choose proper software. Therefore the study to resolve the statics problem is of great importance.In this thesis, a detailed analysis of the near-surface structure is performed to solve serious static correction problems in complex near-surface areas of western China, such as Mountains of China’s Gobi, desert and loess tableland. Then several mature and commonly used static-correction methods of the primary field static-correction, refraction and reflection static-correction technologies are jointly investigated, especially for the usage in complex near-surface conditions.The major study contents are as following:(a) To solve serious static correction problem in complex near-surface area, a novel approach is developed by simplify all of the complex issues, which is a jointed technical by a variety of static correction methods. The issue of static corrections in complex area is a comprehensive systematic project. Firstly, after investigating near surface conditions of the study area and analyzing the origins of static correction, processors are able to select the appropriate effective and economic static-correction methods to be complementary and organic composition, according to the practical situation of near surface. Secondly, the following sequence should be followed: the long-wavelength being first, the mid-to-short wavelength as well as residual static corrections being next to solve the issue of static corrections. (b) The following new techniques and processing flows are proposed: Refraction first-break wave picking is easier and more accurate by preprocessing and post-correction technique such as bandwidth filter, wavelet deconvolution and the similarity of reflection curve; Overall analysis and building near surface model; Using Kriging interpolation and the intermediate reference datum to calculate statics for a integrated near-surface modeling; forward modeling and inversion by the first-arrival ray tracing; Applying EGRM to create a near-surface initial equivalent model; RRS to calculate statics; Comprehensive statistic analysis of the first-break time of refraction in Common-Source-Point, Common-Receiver-Point, Common-Offset-Point and Common-Middle-Point to solve residual static-correction; Adaptation in integrative global-optimization reflection-wave residual static-correction.(c) Through the development, improvement, innovation and combination of those technologies, combined with computer software, new technology of computer and actual processing demands of customers, conducting system analysis and system design, focusing on the optimization of source codes, a set of commercial software products LD-SAGA are researched and developed, which integrated the previous mentioned technologies. They provide a lot of comprehensive static-correction techniques, e.g., data management, data visualization, static correction to analyzing and QC functions of the results. It is an effective tool to research and solve the practical problem of static correction for complex regions.The practical data processing indicated that the joint application approaches can achieve good results for solving the static-correction issues in the complicated region, through utilizing yield survey information, refraction and reflection of seismic data. |
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