Abstract：Ordovician—Triassic is explored targets in Tahe Oilfield, and crud oil in Cambrian-Ordovician moved into the reservoirs in each above-mentioned layers along the fractures, forming structural, lithologic and various composite oil-gas reservoirs. Comprehensive analysis of 3-D seismic data, logging and core data, identification and prediction of spatial distribution rule of sandstone and karst reservoirs controlled by various sedimentary facies are an important technology in oil-gas exploration and development in Tahe Oilfield. Total six seismic facies are identified in the area, including Triassic typical braid and meandering river; Carboniferous Kalashayi Formation low-sinuosity river and Bachu Formation lagoon-barrier facies; Devonian delta seismic and Ordovician karst facies. The along-horizons amplitude slices in 3-D seismic data, slop of reflection strength, waveform classification and logging traces are main tools in finding depositional framework, sand body and distribution of reservoirs.
