The Near Vertical Reflected Seismic Data Acquisition And Processing In Complicated Geological Condition In The Tibetan Plateau

With the development of national economy and the increase of energy sources' demand, as well as the strategic future evaluation of oil and gas in Tibetan Plateau, the seismic researching come into the area of complicated geological condition accordingly, and bring some difficulties for the seismic data gathering and processing. The paper introduced the ecumenic method of seismic data gathering and processing in normal area firstly, then discussed the expert technique for gathering and processing in the complicated geological condition area by my practice, analyzed the problems of complicated area and the difficulties in gathering. The author have joined in the data gathering and processing of two programs: the research of 2D seismic reflect section in Qiangtang Basin and the exploration of deep seismic reflected section in RuoErGai-Western Qinling Orogen. Study the technique of seismic gathering and data processing, contraposed the complicated seismic geological condition in Tibetan Plateau especially, in study, research the static correction and residual static. From the single shot, we may know that one of the most importance problems in Tibetan Plateau is how to do the static correction well. In the paper, there are some static techniques used in the mountain area in internal domain, and based on the geological condition of this section, computed the static correction in two steps: first, corrected to float datum, then do the refraction static by the information of first break picking. The way is useful to single shot in that area, but from the final section, it is not good enough in in-phase shaft, and shows that the static correction is not bon, so we must research more effective static methods. Do the residual static correction after velocity analysis, the key of correction is how to chooseagoodfiducial stratum, otherwise, it will destroy the continuity of in-phase shaft. Mr. Meng Er sheng has pointed out that it will be a better effect by using a deep-seated fiducial stratum if there is not a good one in flat area. In the paper, computed the residual static correction by the stratum of 1500ms,3000ms and 4500ms respectively, from the contrast of the sections, it changed well by using deep-seated stratum than using low-seated stratum, and it showed that what Mr. Meng said was right. So it is very important to select a right stratum while doing the residual static correction.