| Based on the reliable internals reflection texture and external shapes of the seismic sequence units in Huagang Formation in Xihu Sag, seismic facies of it are divided and named. Amplitude, continuty and other seismic parameters are used in description of seismic sequence units. Four seismic subsequences are divided and several seismic facies in them are identified, which include the foreset, lenticular, mound and parallel-subparallel seismic facies. The last facies is also divided into D1, D2, D3 and D4 subfacies. These seismic facies show not only differentiation in spatial distribution but also hereditability in vertical evolution. After applying drilling, logging and other geological data to interpretation of seimic facies validation and constraint, and then transforming seismic facies into sedimentary facies, it can be ascertained that the Huagang target beds in this area are the sediments in continental environment, in which develop braided river facies, lacustrine delta facies and shallow lake facies as well as fan delta facies in the steep eastern slope. |
