The fractured-cavity carbonate reservoir possesses the features of severe heterogeneity, complex structure of reservoir space.
In addition, filled fractures make a greater contribution to the reservoir space of Є1b2 shale through dissolution.
However, the major effective reservoir space types of No. 3 tight oil layer are structure fracture and lamellation fracture.
The reservoir space types of Lucaogou Formation can be divided into the effective pore reservoir space (primary intergranular pore, intercrystalline pore and dissolved pore), effective fracture resrvoir space (structure fracture, lamellation fracture and abnormal pressure fracture) and ineffective reservoir space (intracrystalline pore and organic pore), respectively.
The fracture cavity carbonate reservoir space types include primary dissolved pores, incompletely filled underground rivers, unconformities, fractures formed by multi-stage faults, and others.
Furthermore, the major effective reservoir space types of No. 2 tight oil layer are primary intergranular pore, intercdrystalline pore, lamellation fractures and structure fracture.
Matrix porosity and permeability are low in the Lower Ordovician carbonate reservoirs of the Taxinan area, and reservoir space is composed of karst vugs and fractures.
Dissolved pore, structure fracture, lamellation fracture and abnormal pressure fracture are the major effective reservoir space types of No. 1 tight oil layer.
The massive accumulation of the liquid-rich hydrocarbons needs four fundamental formation conditions: stable tectonic background, widespread high quality source rocks, large-scale tight reservoirs with massive reservoir space, and co-existence of source and reservoir.
In this paper, a two-dimensional visual fractured-cavity carbonate reservoir model was developed based on the distribution feature, space structure and connection type of fractures and caves in reservoir space.
The reservoir space is dominated by four types of karst vug, including vesicular vugs, enlarged dissolved vugs along fractures, tabular vugs and isolated vugs, and three types of fractures, including medium-high-angle fractures, low-angle and horizontal fractures as well as irregular fracture networks.
