균열과 다공질 유동의 특성 규명을 위한 수치해석적 연구

다국어 초록 (Multilingual Abstract)

Recently, commercial development of unconventional gas resources including shale gas is being rapidly expanded, centring in North America. For developing these very tight shale gas formations, both long reach horizontal drilling and multi-stage hydraulic fracturing techniques are required. It is possible to produce natural gas by means of the artificial fracture networks created by these techniques. Consequently, the flow in a shale gas reservoir exhibits a very complex flow behaviour, compounded with pipe flows in vertical and horizontal wells, reaching generally 4 to 7 km in distance, diffusion flows in very tight shale rock matrices, porous flows in sand formations and propant banking areas, and fracture network flows through both natural fractures and hydraulic fractures in a shale formation. Therefore, it is required to devise and apply new reservoir flow analysis theory and methods which can accurately consider complex gas flow owing to the geometric characteristics and distributions of various pores and flow paths within a shale gas reservoir. Particularly, a new analysis method which can properly simulate fracture and porous flows having various ranges of porosity and permeability should be necessarily proposed. Hence, in this study, the influences of convection and diffusion forces in the momentum equation for porous flow, the core factors inducing the flow differences between the general range of porosity and permeability in normal porous media and the high range of that in fractures and so on, were closely examined by CFD method. Finally, it was tried to quantify them by each porosity and permeability range of various porous media and to be linked to a new analysis method to distinguish and compound fracture and porous flows.