Abstract:

Favorable exploration areas and oil and gas reservoir can be predicted more accurately though analysis of sequence architecture pattern in different tectonic settings. Using seismic, drilling, logging, core, paleontology and so on, according to sequence interface characteristics, Lower Cretaceous in Huhehu depression is divided into 3 second-order sequences, 5 third-order sequences. On the base of structure background, Huhehu depression is divided into fault controlled steep slope zone, gentle slope fault terrace zone and depression zone. Different tectonic units show different sequence architecture patterns: fault controlled steep slope zone sequence architecture patterns, gentle slope fault terrace zone sequence architecture patterns and depression zone sequence architecture patterns. The results show that different tectonic units have specific characteristics of sequence architecture patterns and sedimentary system composing model, and different types of sequence architecture patterns control oilgas formation models. Fault-lithology oil and gas reservoir, fault oil and gas reservoir mainly develop in fault controlled steep slope zone sequence architecture patterns; Fault-lithology oil and gas reservoir, and stratigraphic overlap oil and gas reservoir mainly develop in gentle slope fault terrace zone；Authigenic reservoir lens reservoir mainly develops in depression zone. Moreover, depression edge can develop faultlithology oil and gas reservoir.

Key words: Huhehu depression, Lower Cretaceous, tectonic units, sequence architecture patterns, pool-forming pattern, petroleum gas