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This paper uses the theory of sequence stratigraphy, sedimentary petrology, sedimentology, geophysics, etc., to carry out seismic sedimentology of the strata of the Qaidam Basin the Unan - grass Beach Youshashan (N21). During the traditional logging, mud logging, coring data analysis based on the combined technology of seismic sedimentology, geological research by the point and the surface, by the face and body to expand, refine and in-depth study of sedimentary microfacies development characteristics. The work area is located in the Qaidam Basin, western depression area, overall a plunge from southeast to northwest Western nasal anticline, sediment source is located in the work area in western Kunlun Mountains, sediments of generally from west to east trends handling but at Unam - grass beach tectonic zone, due to local structural factors, the the N21 period sediment source showed the West - North West, South - South East to the co-existence of the phenomenon. Comprehensive analysis of the geological data of the core, logging, logging and sedimentary structures, and combined with the results of previous studies, established Unam - grass beach area Youshashan sequence stratigraphic framework of the program, under Youshashan Formation as a whole as a three-layer sequence units, divided into seven four-layer sequence (SQ of Ⅰ-SQ VII), 174 five-layer sequence, and established the basic sedimentary facies model. The major developmental Depression under Youshashan strata shore shallow lake dam lakes context - the delta front depositional systems, stratigraphic Lake withdrawal process from the old to the new performance types of sedimentary facies gradually evolved from a single shore shallow lake dam delta front - Bin shallow lake dam depositional systems. On the basis of the above understanding, the use of seismic sedimentology (90 ° phase switching frequency processing and stratigraphic slices), stratal slicing body to carry out the work area of ??3D seismic data, by extracting corresponding sequence within the boundaries of the earthquake are square root amplitude attribute, combined with the understanding of the sedimentology, to map out a four layer sequence of sedimentary microfacies plan under Youshashan using the geometric interpolation techniques in seismic layer, carry on the under Youshashan 174 five sequence stratigraphy slice clear sedimentary evolution of the internal characteristics of each of the four layer sequence. In the the sedimentary microfacies chart based on stratigraphic slices divided seven sedimentary microfacies type: littoral and shallow lake dam, shallow lake shore, shallow lake mud, delta front underwater distributary channel, delta front underwater distributary river delta front mouth bar, delta front sheet sands. Through a comprehensive analysis of the delta front sand and shore shallow lake dam body is the most favorable reservoir in the area, with good prospects for oil and gas exploration.
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