Logging Data High-Resolution Sequence Stratigraphy

The recognition and contrast of bed sets in parasequence is difficult in terrestrial basin high-resolution sequence stratigraphy. This study puts forward new methods for bed set boundary identification and contrast on the basis of manifold logging data. This paper considers the formation causes of calcareous interbeds, shale resistivity differences and the relation of reservoir resistivity to altitude, on the basis of log curve morphological characteristics, core observation, founding slice, X-diffraction and scanning electron microscopy. The results show that the thickness of calcareous interbeds is between 0.5 m and 2 m and its thickness is increased on weathering crusts and faults. Calcareous interbeds occur at the bottom of a distributary channel and the top of a distributary mouth bar. Lower resistivity shale (4-5 Ω·m) and higher resistivity shale (>10 Ω·m) reflect differences in sediment fountain or sediment microfacies. Reservoir resistivity increases with altitude. So calcareous interbeds may become a symbol of recognition and isochronous contrast bed sets, and shale resistivity differences may confirm the stack relation and connectivity of bed sets. On the basis, the author founds the high-resolution chronostratigraphic framework of Xi-1 number in Shinan area in Junggar basin, and confirmed the connectivity of bed sets and oil-water contact. In this chronostratigraphic framework, the growth order, stack mode and space shape of bed sets are a qualitative and quantitative token.