Abstract:

The rock types are various in Cangfanggou Group of the Baijiahai-Wucaiwan area. The reservoir is of crack-pore type. The diagenetic types are various and complex, such as mechanical packing, cementation and so on, and the diagenetic stage is in late diagenetic epoch. The lithology, sedimentary facies and diagenesis have different influences on the reservoir properties Six sandbody types are identified in Cangfanggou Group, which are alluvial-fan-braided-river-glutinite-body, underwateralluvial-fan-glutinite, fan-delta-glutinite-body, sublacustrine-fan-glutinite, near-shllow-lake-beach-dam-body and meanderingriver-fluvial-channel-sand-body.The evaluation criterion about the reservoir is established by detailed analysis on the sandbodies.Sandbodies of Fan delta and sub-lacustrine fan are the most beneficial reservoirs. Sandbodies of alluvial fan and subfluvial alluvial fan are more beneficial reservoirs.

Key words: Baijiahai, Wucaiwan, Cangfanggou Group, reservoir, sandbody