High-resolution seismic reservoir prediction of SN13 well in desert area of the Junggar Basin

In the desert area of the Junggar Basin, the high-frequency attenuation of near surface seismic data is large, the seismic resolution of vibroseis 3D seismic data is low, and it is difficult to predict thin channel sandstone reservoirs. By applying the “two widths and one height” acquisition and processing technology, the seismic data in the large desert area of SN region has a high signal-to-noise ratio and good quality. The dominant frequency bandwidth of the three-dimensional seismic target layer in SN region is 5-45Hz, with an apparent main frequency of about25Hz and a seismic resolution of about 25m. The high impedance river sand reservoir corresponds to seismic wave valleys, while the seismic characteristics of low resolution seismic wells are inconsistent. The seismic interpretation layer of the reservoir is a valley. Research on dual well microseismic logging shows that high-frequency attenuation of seismic waves is mainly near the surface. Therefore, significant breakthroughs have been made in broadband high-resolution seismic technology using near surface high-frequency attenuation recovery methods, with an advantageous bandwidth increased to 5-120Hz, a dominant frequency of 75Hz, clearer interlayer faults, a seismic resolution of about 8m for river sandstone reservoirs, and a seismic resolution increase of over 200%. High impedance river sandstone reservoirs correspond to high-resolution seismic strong reflection peaks, with consistent well seismic characteristics. High resolution seismic interpretation has identified the reason for oil production in the SN13 well located at the bottom of the structure and water production in the S142 well located at the higher part of the structure in the same layer. According to high-resolution seismic analysis, the S142 well was drilled on an abandoned river channel, and the amplitude of the oil producing reservoir from the sn13 well weakened to the s142 well. The water producing reservoir of the S142 well is the lower reservoir in the river channel. The high-resolution seismic geological interpretation in the SN area predicted the distribution of favorable channel sandstone reservoirs, and the industrial oil flow was obtained from the posterior wells such as H8. The strong reflection of the high-resolution seismic channel sandstone layer corresponds to the Gr interface, which indirectly illustrates the geological significance of high-resolution strong reflection waves (Fig.1).