Numerical Modeling of Hydraulic Confinement around Crude Oil Storage Cavern in Fractured Rocks: Direct Application of DFN Concept

Abstract

Unlined rock caverns for hydrocarbon storage are mainly excavated in strong and stable rock masses with very low-permeable matrix, where hydrocarbon migration is only possible along fractures connected to the cavern boundaries and their networks. In this paper, the hydraulic confinement around a URC cavern was simulated by directly applying distinct fracture network (DFN) model. First, a computational code, so-called “FNETF”, was developed to generate DFN and solving fluid flow equation along fractures. Proper internal hydraulic boundary condition of water-hydrocarbon interface at cavern boundary was defined based on the fluids properties and applied in the FNETF code. Fluid flow in fracture network was numerically simulated for different outer boundary hydraulic conditions assigned by different groundwater pressures of water curtain. Finally, the assessment achieved to expect the occurrence of hydrocarbon.