Fine description of structure research of Lishui sag, East China Sea Basin

Considering that the available data in Lishui sag is limited, seismic data were used to recognize the important interface and sequence; this paper divided the lower segment of Mingyuefeng formation into four systems tracts of HST, TST, LST, and FSST and the upper segment of Lingfeng formation into three systems tracts of HST, TST, and LST, the others were divided into two systems tracts of HST and TST. As there were only four wells in the lower segment of Mingyuefeng formation, the well top data and well logs were not enough, so the seismic data played a significant role in building structural model which included fault model and horizon model. Instantaneous phase profile explained small faults more clearly and accurately combining seismic interpretation with coherence cube and variance cube. The faults were analyzed, and integrated structure of the lower segment of Mingyuefeng formation was constructed. The integrated 3D geological model was a valuable tool of reflecting geologic body with great reality and can accurately represent and describe the complex reservoir heterogeneity.