The Dengying Formation fossil oil pool of Upper Sinian in Nanshanping

Cili County

Hunan Province was formed in Late Silurian-Early Devonian Period. The reservoir spaces were corroded pores

holes and fractures in Dengying Formation dolomite . The Late Jurassic-Early Cretaceous Yenshan movement caused the uplift and erosion of the covery bed of the fossil pool

thus resulting in complete damage of the pool. The discovery of the fossil pool suggests that West Hunan-Hubei Depression had similar hydrocarbon generation and pool-forming process as Weiyuan Gasfield

in Sichuan Province. The difference is that Yenshan movement had little influence on Weiyuan Gasfield

but the Cili fossil oil pool was seriously damaged by the movement. So it is considered that fovourable oil and gas pools could be found in Western Hunan-Hubei Region if favourable covety beds and traps could be found in the area.