Abstract:

A study of the Ordovician fractured-vuggy carbonate reservoirs in the Tahe oilfield is carried out to determine the concept and features of paleo-cavern systems in these reservoirs.Also included in the study are the formation,evolution,and deformation of these systems as well as their role in compartmentalization of reservoirs.The study points out that the compartmentalization of these reservoirs is mainly caused by collapse,filling,and fracturing processes of the pale-cavern systems.It is therefore suggested that these heterogeneous reservoirs formed by karstification and tectonic movements shall be described systematically and hierarchically from a karst system level(paleo-cavern system)and reservoir level(fracture-vug unit).The idea is applied to the study area and gains positive results.

Key words: fractured-vuggy carbonate, cavernous reservoir, paleo-cavern system, oil/gas field development, Tahe oilfield