A method for judging sand body connectivity based on seismic fusion attributes: A case of the Bozhong Sag

The fine description of sand bodies in the lower member of the Minghuazhen Formation (Neogene) in the middle and shallow layers of the Bozhong Sag, Bohai Bay, is limited due to thin interbeds and insufficient seismic and logging data, making it difficult to determine the connectivity of sand bodies. Based on the actual seismic, logging, and geological data in the study area, a corresponding model was established based on the actual characteristics of the sand bodies in the study area, and suitable seismic attributes were verified and optimized through the wave equation method in forward modeling technology. By using a minimum horizontal distance of 1/8 of wavelength and a vertical overlap of 1/6 the wavelength, the root mean square amplitude attribute, sweet spot attribute and main frequency attribute were more effective than using seismic data in determining the connectivity of sand bodies in mid-to-shallow layers. According to the verification of Well X5 logging in the study area, the correlation between seismic fusion attribute and sand body thickness was significantly improved, and the thickness of sand body itself and the distance of contact points among sand bodies could be quantitatively calculated, which played a good role in determining the connectivity of sand bodies in the study area.