Application Research Of Coalfield Seismic On Refraction Static Correction Method Under Complex Near-Surface Area Of Shanxi

Static computation is a key step to deal with coalfield seismic data of complex surface conditions. SNR of primary arrival refraction is higher and recognized easily sometimes when SNR of changeable and complicated seismic data reflection is low at near-surface layer. Therefore using velocity structure of refraction playback near surface to estimate static correction value has been become important and efficient tool. The processing results will lead to wrong structural interpretations directly and create drilling loss .So how to solve the static correction problems caused by the changes of near surface factors with refracted first-break information is a key problem for data processing. For solving the static correction problems under complex near-surface conditions, we should consider nature characteristic and take full advantages of refraction first-break information so as to reflection static methods are used iteratively to solve the residual static problems. To solve serious static correction problems in complex near-surface areas of Shanxi coalfield seismics, the article uses for reference of predecessor investigative success, different refraction first-break static methods are studied and approached in this thesis. The main study contents are as follows:(l)It expounds clearly primary arrival refraction static correction method at present status and existent problem; according to loess tablelands and serra region in point, it analyzes the principal difficulty in loess tablelands and serra area seismics.(2)It has been expounded that travelling fundamentals of layer medium and continuous medium refraction and researched on refraction odograph equation and odograph characteristic of continuous medium.(3)Firstly, we introduce concept of corresponding first arrivals refraction static correction from which educe the matter needed to solve about refraction static correction. Secondly , we expound existenting pros and cons of different kinds of refraction static correction methods ,and adopt EGRM primary arrival refraction static correction method ,combining geologic feature of complex area of Shanxi.(4)Through the practical application of Jincheng and Xinzhou in shanxi province, it is proved that adopting EGRM can solve effectively loess tableland surface and serra surface area on processing. It is suggested that databases of high-precision thickness, lvl velocity and high-speed layer velocity and so on should be founded to solve static correction of complex surface area of Shanxi , thus primary arrival could be picked accurately and precision of static correction is enhanced .Select adaptive velocity ray equation through combining nature characteristic of complexity surface of Shanxi, It is proved by data that EGRM static correction is good practice to solve complex area of Shanxi at process of treatment.