Study On Triassic Sedimentary Facies And Seismic Reservoir Predict In Yuqi-Caohu Area Of Tarim Basin

The paper used drilling and 3D seismic data, carried out fine Triassic stratigraphic correlation and sedimentary facies analysis, deal with some of the Triassic wedge-shaped reflection phenomena such as the foreset reflection, the reason of onlap piching reflection and geological significance and the low of time-transgressive phenomena, focusing on finding and ascertain the allocation of sand body and the position of wedge out, provided some reference for looking for the favorable exploration targets in the area.Apply seismic attribute extraction, forward modeling, inversion and other methods, associate with statistical analysis of sand content in well point, make up sedimentary facies and electrofacies plan of the main section of sand group or stratum group. Suspect Ketuer group in Lower Triassic of the work area should be shallow lake deposits, locally developed fan delta; the upper, middle and lower oil sandstones are mainly braided river facies, upper oil sandstone at AD5 Well developed braided delta and meandering river; and the mudstone between the three sandstones should be shore shallow lake or floodplain deposits, locally developed deep lake.Reservoir analysis showed that, the porosity of sandstone in Yuqi-Caohu Triassic ranged from 15%～20%, and the permeability between 10 to 1000md, pertain to reservoirs of moderate or higher permeability. Average porosity is 5% lower than Tahe oil field at Triassic and permeability is 200-300md lower. Reservoir space is made up of primary origin intergranular and secondary porosity, the totality of pore structure isⅡB-ⅠA level, the reason of the reservoir deterioration than Tahe area is that the provenance closer and low sandstone structure and larger of depth.Through the analysis of the ancient tectonic evolution and oil and gas migration, the degree of fault development and a favorable combination of reservoir and cap rock, point out that the clues of piching out on southwest of YQ10 well in Triassic upper oil group and updip piching out on YQ4 well pebbled sandstone, ect.