Application of INPEFA technology to sequence stratigraphy of the third member of Funing Formation, Nanhua block, Qintong Sag, North Jiangsu Basin

The maximum entropy spectrum analysis technique provides the frequency trend line (INPEFA curve) by analyzing the synthetic prediction error filtering of logging curves, and using the trend turning point of different amplitude of the INPEFA curve to identify the interface of different order sequences.Through the INPEFA treatment of the GR curves of the third member of Funing Formation in the Nanhua block in the Qintong Sag of the North Jiangsu Basin, the Ⅲ and IV oil groups were divided into 13 five-level sequences, and then the sand body connectivity among three wells with close distances within the block was compared in an isochronous framework established by INPEFA curves. Comparing the sand body connectivity, it was concluded that there were two sand layer groups and oil layer groups connected in the small layer. The logging curves processed by INPEFA technology can extract the characteristics of cyclic trends hidden in conventional logging curves. According to the INPEFA curves with similar trends in the three wells, the sedimentary environment in this area changed roughly the same, from regression to transgression.