Reservoir forming conditions in low buried hill of Jiyang depression

Futai oilfield is located in the second step on the downthrow of Chengnan steep belt in Jiyang depression, showing below slope feature. There are two types of buried hills developed on the second step buried hill zone, i.e. Guliang low buried hill between two sags and the low subtle buried hill in hydrocarbon kitchen. The former was covered by s_3 and s_4 of Shahejie formation, Palaeogene, Cenozoic, with Carboniferous-Permian as caprock on the top, Ordovician-Cambrian as reservoirs, and Sinian gneiss as basement, forming multi-layer inner buried hill block reservoir. The latter has the unconformity between the bottom of s_3 and the top of Ordovician as caprock, and Cambrian and Ordovician as main reservoirs, forming inner buried hill reservoirs with oil generated in a later time and preserved in ancient formation. Among which, Cambrian is a newly discovered regional prolific oil system. Hence, to look for similar buried hill reservoirs on the steep of Jiyang half fault depression will achieve certain exploration breakthrough.