HighResolution Sequence Stratigraphy of Shanxi Formation(Permian) in Northwestern Portion of Ordos Basin

Key words: 
• Ordos basin /
• high resolution sequence stratigraphy /
• baselevel cycle /
• sequence stratigraphy framework

Abstract: Highresolution sequence stratigraphy division of Shanxi Formation in northwestern part of Ordos basin has been put forward according to principle〖KG*2〗of base level cycle based on 4 outcrops and 35 core description and 305 well logs. As a component of longterm baselevel decreasing cycle, Shanxi Formation constitutes a mediumterm cycle, which can be subdivided into 5 shortterm cycles in ascending order(SSC1,SSC2,SSC3,SSC4,SSC5). Based on the sequence structure, and stack style and space variation, the highresolution sequence stratigraphy correlation framework〖KG*2〗is established to discuss sedimentary facies styles and controlling factors and physical〖KG*2〗property. The most favorable reservoir bodies were formed during early stage of semiascending cycle of short-term baselevel cycle. Reservoir bodies are mainly composed of delta plain distributary channel and delta front subaqueous channel. Here, the monofactor mapping method is adopted to study space distribution of the reservoir〖KG*2〗bed.