序界面的识别是层序识别与划分的基础。层序边界识别标志包括:①地震剖面上

The identification of sequence interface is the basis of sequence identification and division. Sequence boundary identification signs include: ① Identification signs on the seismic profile: ablation (cutting, erosion), overshoot, and overshoot; ② Drilling log identification signs: lithology, electrical mutation, etc .; ③ deposition Geological signs: paleo-weathering exposed surface, river bed retention sediment, sedimentary cycle change, lithology, vertical loss and mutation of lithofacies, cut surface and coastal supersurface; ④ geochemical symbol: special enrichment or depletion of elements . <br>The Xingouzui Formation of the Paleogene in the central and southern Jiangling Sag is dominated by terrestrial detrital deposits, and brown-red and gray paste mudstones are developed in some areas, accompanied by other evaporite deposits. Sedimentary cyclicity is concentrated in the vertical lithological combination of phase sequence changes and grain sequence changes and the evaporite sedimentary rhythm. From the log, sandstone shows low apparent resistivity and low natural gamma value (GR, argillaceous rock shows low apparent resistivity and high natural gamma value (GR evaporite shows high resistivity and low natural gamma value Gamma value (GR. Therefore, the sequence stratigraphy is divided according to the natural gamma and the longitudinal change of the lithology profile as the sedimentation rotation

The recognition of the sequence interface is the basis of the sequence recognition and division. The identification marks of the sequence boundary include: (1) the identification marks on the seismic profile: the phenomenon of cutting (cutting, erosion), the superphenomenon, the super-super phenomenon; Signs: paleo-weathered exposure surface, riverbed residual deposition, sedimentary rotation change, rock, rock phase in the drooping loss and mutation, cut surface and coastal supersurface; (4) geochemical mark: special enrichment or poverty of elements.<br>The ancient near-line Xingou Tsui group in the south-central jiangling depression was mainly land-sourcedebri deposition, and local areas developed brown red and gray paste mud rock, accompanied by other evaporative rock deposits. The sedimentary rotation is concentrated on the phase sequence change of vertical rock composition and the change of grain sequence, as well as the sedimentary rhythm of evaporative rock. From the logging point of view, sandstone is characterized by low-vision resistivity, low natural gamma value (GR, mud rock as low-vision resistivity, high natural gamma value (GR evaporation rock is shown as high resistivity, low natural gamma value (GR). So according to the longitudinal changes of natural gamma and rock profiles as sedimentary spins are returned to divide the sequence formations.

The recognition of sequence boundary is the basis of sequence recognition and division. Sequence boundary identification signs include: ① identification signs on the seismic section: cutting (cutting, erosion) phenomenon, up overtaking phenomenon, top overtaking phenomenon; ② identification signs of drilling and logging: lithology, electrical mutation, etc.; ③ sedimentary geological signs: paleowind exposed surface, riverbed retention deposit, sedimentary cycle change, lithology, lithofacies loss and mutation in the vertical direction, cross-section and coastal super surface; ④ Geochemical mark: the special enrichment or impoverishment of elements.<br>Neogouzui formation of Paleogene in the south central part of Jiangling depression is dominated by terrigenous clastic deposits, with brownish red and grey gypsum bearing mudstones developed in some areas, accompanied by other evaporite deposits. The sedimentary cyclicity is mainly manifested in the change of facies sequence and grain sequence of vertical lithologic association and the sedimentary rhythm of evaporite. From well logging, sandstone shows low apparent resistivity and low natural gamma value (GR), while argillaceous rock shows low apparent resistivity and high natural gamma value (GR evaporite shows high resistivity and low natural gamma value (GR). Therefore, the sequence stratigraphy can be divided according to the vertical change of natural gamma and lithologic profile as sedimentary gyration