In contrast, numerical or analytical calculating equivalent permeability from discrete fracture geometries provides an efficient way for estimating rock permeability and links the small scale fracture geometries and equivalent permeability for field-scale models, which is also known as upscaling. The continuum approaches are often applied to explore the bulk rock flow regime for a scale of the measurement.
![porus rock porus rock](https://cdna.artstation.com/p/assets/images/images/018/143/348/large/ben-wilson-rock-porous-a-render-2.jpg)
Such measurements can be roughly classified into continuum approaches and discrete fracture approaches. Permeability of fractured rocks can be estimated by laboratory experiment, borehole flowmeter, field pumping test, discrete fracture characterization data from core samples, borehole well logs, and outcrops.
Porus rock full#
As a quantitative measure of a rock mass’s ability to conduct fluid, permeability is one of the most important properties affecting the flow in fractured porous rocks.ĭue to the high heterogeneity and anisotropy of fractured rocks, the permeability of fractured porous rock generally has a symmetric full tensor form and exhibits scale effects. The interconnected fracture networks in the rock matrix are the primary pathway for fluid to flow underground and have significant importance on practical applications, such as aquifer management, groundwater contamination, hydrocarbon and geothermal energy exploitation, geological disposal of nuclear waste, and coal mine water inrush. Introductionįractures are among the most common structures in the brittle rocks of the Earth’s crust and span a wide range of length scales from millimeter to kilometers.
![porus rock porus rock](https://cdnb.artstation.com/p/assets/images/images/018/143/363/large/ben-wilson-rock-porous-a-render-4.jpg)
![porus rock porus rock](https://img.freepik.com/free-photo/porous-rock-sandstone-texture-background-surface-stone-by-seaside-naturally-occurring-solid-mass_34048-1801.jpg)
The results demonstrate that both the fracture density and length-aperture model influence the equivalent permeability of equivalent fracture models interactively. A power law model is built between the equivalent permeability of equivalent fracture models and fracture density of discrete fracture models for the correlated aperture-length models. The average dimensionless equivalent permeability for the equivalent fracture models is well described by an exponential relationship with the correlation exponent. When the minimum fracture length and the number of fractures increase, the process that the diagonal equivalent permeability tensor components change from a power law like to a lognormal like and to a normal-like distribution slows down as the correlation exponent increases. Results indicate that the spatial distribution of equivalent permeability varied with the correlation exponent. The equivalent fracture models are built by the multiple boundary upscaling method.
![porus rock porus rock](https://thumbs.dreamstime.com/z/pebble-porous-basalt-mineral-stone-isolated-macro-shooting-natural-rock-specimen-pore-filling-zeolite-calcite-chlorite-68396245.jpg)
Two-dimensional discrete fracture models are generated with varied correlation exponent ranges from 0.5 to 1, which indicates different geomechanical properties of fractured porous rock. This study quantitatively investigated equivalent permeability distributions for fractured porous rocks, considering the impact of the correlated fracture aperture and length model. However, it is difficult to constrain the permeability distributions for equivalent fracture models as these are strongly influenced by complex fracture properties. Estimating equivalent permeability at grid block scale of numerical models is a critical issue for large-scale fractured porous rocks.