The reservoir rocks in Shuguang buried hills

Liaohe fault depression are mainly composed of both sandstone and carbonate rocks. A large proportion of reservoir space is secondary

including vugs and fractures. In Shuguang buried hills the medium-high buried hills are characterized by the so-called "fracture development in upper part but vug development in lower part"

that is

the tectonic fractures are common in the upper part of buried hills without so-lutional voids

whereas the large numbers of solutional voids most likely to occur in the lower part of buried hills. The development belt of fracture and secondary pores is also present in gentle buried hills

but its buried depth is deeper than that in medium-high buried hills. The distribution of reservoir rocks in buried hill is related to the following factors:(1) a vast amount of solution vug and fracture formed by crust uplift

compressional strike-slip orogenesis

weathering and denudation during the late Paleozoic-Mesozoic era; (2)new fissures formed by the progressively deep burial of reservoir rocks in Shuguang buried hills during the Cenozoic strike-slip extension; (3)redistribution and reworking of the existing pores and fissures in Shuguang buried hills due to the steady burial diagenesis of overlying strata.