dentification of Lacustrine Turbidite Sand Bodies Based on Seismic Sedimentology: A Case from the Niu 20 Block of Dongying Depression

It is difficult to predict lacustrine turbidite sand bodies with seismic data due to their small volume, fine grain size, small thickness of single layer and drastic facies change, and the shielding effect of the overlying thick deltaic sand body, in addition to the low resolution of existing seismic data. Taking the Niu 20 block of the Dongying Depression as an example, this paper adopts the principles and methods of seismic sedimentology to make interpretation of seismic data. Sedimentary models are combined together with seismic reflection characteristics and time-frequency analysis under the constraint of well points, and thus the isochronal sequence stratigraphic framework was established by identification of the front boundaries of sedimentary facies.The resolution of seismic data is enhanced. The seismic phases with lithological and stratigraphic significance are the keys to identify and predict lacustrine turbidite sand bodies. Under the control of isochronal interface, using forward modeling method as a tool, it is considered that the combination of mixed phase wavelet frequency extension technology and frequency division technology can effectively improve the main frequency and resolution of seismic data. The reflection lobe can be brought to the center of the stratum by 90 degree phase conversion, which realize the lithological and stratigraphic significance of seismic phase.Finally, the combination of strata slice and seismic attributes can effectively identify and predict turbidite sand bodies.