Lithlogical Reservoir Seismic Description Research In Chepaizi

The Chepaizi area is a block in Zhungaer basin, which belongs to SINOPEC. The exploration experience in this area is relatively poor. Up to now, 22 exploration wells were drilled, among them, the industrial oil & gas was got only in 3 wells, and 3 wells were with low production. The exploration result is not good enough. The main reason includes that the identification and description methods are not mature, which limited to improve the exploration success ratio.In order to study and summarize a set of seismic data description technology which adapted to lithological hydrocarbon reservoir exploration in Chepaizi area, and to provide technological support to this area's lithological reservoir identification and description, based on the real drilling data, the check to well log curve and the calibration to curve anomaly about the drilled 22 wells in Chepaizi area have finished, and under this foundation, the relation between the well log's surface feature ( such as porosity, permeability, resistivity, effective thickness, etc. ) and the oil-bearing is analyzed based on 40 wells in Chepaizi-2 developing area; the synthetic seismogram of all the exploration well and partial developing well in this area is calibrated, and finely horizon calibration is undertaken。According to VSP calibration, synthetic seismogram calibration and reflection feature of special seismic boundary, it is decided that the 3D seismic data in this area is positive polarity; based on the velocity research and combined with real drilling data, the forward model of oil-bearing sand body is created, and made it clear about the seismic reflection feature of the good lithlogical sand; meanwhile according to the analysis of real drilling data, it is found that the spontaneous potential curve can distinguish sand shale with good result, so we rearrange the sonic log and undertake psedo-sonic inversion, the predicted sand matches well with drill data in the inverted section, and also the sand boundary is clear, we can distinguish the sand shale effectively.According to the match degree between drilled well result and various seismic attribute, attributes sensitive to portable sand strongly are choosed from all attributes, such as RMS amplitude, arc length, average instantaneous frequency, etc. The portable attribute feature of portable sand is visible. Combined with inversion and horizon flattening, we analyzed the lithlogical trap, and optimized 7 targets, and 3 well suggestions are accepted, the predicted oil geological reserve is 500×10~4t. Through this research, we summarized the "bright-spot like" technology series which fit to lithlogical reservoir exploration in this area, and formed a seismic description method which suited for the lithlogical reservoir in Chepaizi, and the result was tested by drilling data.