Permeability (earth sciences)

About: Permeability (earth sciences) is a research topic. Over the lifetime, 15424 publications have been published within this topic receiving 288535 citations.

Study of water movement in concrete

Abstract: An investigation on the movement of water in 100% Portland cement concretes is presented. The water diffusion and sorptivity tests, together with the accelerated water permeability test, are performed to determine the transport parameters that characterise the mechanisms of water diffusion, sorptivity and permeability in concrete respectively. The effects of pore humidity, ambient temperature, environmental relative humidity, applied hydrostatic pressure gradient and water-cement ratio are also explored. The results obtained from the tests on water diffusion, sorptivity and permeability show good agreement with those reported in the literature. The study of water movement has practical implications on the prediction of transport and distribution of aggressive chemical agents in concrete, as well as on the development of rational and quantitative durability assessment for concrete structures exposed to different climatic and environmental conditions.

Imbibition of hydraulic fracturing fluids into partially saturated shale

Abstract: Recent studies suggest that imbibition of hydraulic fracturing fluids into partially saturated shale is an important mechanism that restricts their migration, thus reducing the risk of groundwater contamination. We present computations of imbibition based on an exact semianalytical solution for spontaneous imbibition. These computations lead to quantitative estimates of an imbibition rate parameter (A) with units of LT−1/2 for shale, which is related to porous medium and fluid properties, and the initial water saturation. Our calculations suggest that significant fractions of injected fluid volumes (15–95%) can be imbibed in shale gas systems, whereas imbibition volumes in shale oil systems is much lower (3–27%). We present a nondimensionalization of A, which provides insights into the critical factors controlling imbibition, and facilitates the estimation of A based on readily measured porous medium and fluid properties. For a given set of medium and fluid properties, A varies by less than factors of ∼1.8 (gas nonwetting phase) and ∼3.4 (oil nonwetting phase) over the range of initial water saturations reported for the Marcellus shale (0.05–0.6). However, for higher initial water saturations, A decreases significantly. The intrinsic permeability of the shale and the viscosity of the fluids are the most important properties controlling the imbibition rate.

Single fluid flow in porous media

Abstract: A comprehensive study on single fluid flow in porous media is carried out. The volume averaging technique is applied to derive the governing flow equations. Additional terms appear in the averaged governed equations related to porosity e, tortuosity τ, shear factor F and hydraulic dispersivity D h. These four parameters are uniquely contained in the volume averaged Navier-Stokes equation and not all of them are independent. The tortuosity can be related to porosity through the Brudgemann equation, for example, for unconsolidated porous media. The shear factor models are reviewed and some new results are obtained concerning high porosity cases and for turbulent flows. It is known that there are four regions of flow in porous media: pre-Darcy's flow, Darcy's flow, Forchheimer flow and turbulent flow. The transitions between these regions arc smooth. The first region, the pre-Darcy's flow region represents the surface-interactive flows and hence is strongly dependent on the porous media and the flowing fluid...

Rock properties in low-porosity/low-permeability sandstones

Abstract: Tight gas sand reservoirs are formally defined by the Federal Energy Regulatory Commission (FERC) as reservoirs with less than 01 md permeability Although this is a permeability-based definition, these reservoirs frequently also have very low porosities ( 15 000 ft (Oil and Gas Investor, 2005)