Characteristics and geological significance of the alluvial fan in Well Yong 95

The characteristics of alluvial fan in Well Yong 95 are studied in respects of seismic facies and single well facies according to core, logging and seismic data. The alluvial fan facies in this well is divided into 3 subfacies of root-fan, mid-fan and end-fan based on single well facies analysis, of which the mid-fan subfacies is subdivided into 3 microfacies of braided channel, inter-braided channel and vertical-bar. It has been proved by exploration that alluvial fan deposition tends to form effective reservoirs which have self-protection ability; an alluvial fan is likely to have fan-anticline reservoirs in its overlying formation or weathered crust reservoirs in underlying basement.