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.

The permeability of fractured rocks in pressurised volcanic and geothermal systems.

Abstract: The connectivity of rocks’ porous structure and the presence of fractures influence the transfer of fluids in the Earth’s crust. Here, we employed laboratory experiments to measure the influence of macro-fractures and effective pressure on the permeability of volcanic rocks with a wide range of initial porosities (1–41 vol. %) comprised of both vesicles and micro-cracks. We used a hand-held permeameter and hydrostatic cell to measure the permeability of intact rock cores at effective pressures up to 30 MPa; we then induced a macro-fracture to each sample using Brazilian tensile tests and measured the permeability of these macro-fractured rocks again. We show that intact rock permeability increases non-linearly with increasing porosity and decreases with increasing effective pressure due to compactional closure of micro-fractures. Imparting a macro-fracture both increases the permeability of rocks and their sensitivity to effective pressure. The magnitude of permeability increase induced by the macro-fracture is more significant for dense rocks. We finally provide a general equation to estimate the permeability of intact and fractured rocks, forming a basis to constrain fluid flow in volcanic and geothermal systems.

Hydraulic fracturing propping agent

Abstract: A high strength propping agent for use in hydraulic fracturing of subterranean formations comprising solid, spherical particles having an alumina content of between 40 and 60%, a density of less than 3.0 gm/cc and an ambient temperature permeability of 100,000 or more millidarcies at 10,000 psi.

Estimating the Hydraulic Conductivity of Landfilled Municipal Solid Waste Using the Borehole Permeameter Test

Abstract: This paper reports the in situ field saturated hydraulic conductivity of municipal solid waste at a landfill in Florida. The saturated hydraulic conductivity ( Ks ) was estimated at 23 locations using the borehole permeameter test, a method commonly used for determination of the Ks of unsaturated soil. The Ks of the landfilled waste was found to range from 5.4× 10−6 to 6.1× 10−5 cm∕s . The Ks was found to be on the lower end of the range of Ks reported by previous studies. The hydraulic conductivity of the waste decreased with depth, the likely result of greater overburden pressures associated with deep locations of the landfill. Permeability values ( kw ) of the landfilled waste calculated based on Ks were compared with permeability values estimated using air as the fluid (air permeability, ka ). Values of ka were found to be approximately three orders of magnitude greater than those of kw . The lower permeability of the waste to water was primarily attributed to entrapped gas. Other factors such as pote...

Permeation of Compacted Clay with Organic Chemicals

Abstract: Hydraulic conductivities were measured on three compacted clays that were permeated with water, methanol, and heptane in rigid-wall and flexible-wall permeameters. The type of permeameter had little effect when the soils were permeated with water. However, rigid-wall permeameters generally yielded much higher hydraulic conductivities than flexible-wall cells when the soils were permeated with organic compounds. Differences in effective stress and confinement along the sidewall of the test specimen are thought to be responsible for the different patterns noted. Permeation of water-saturated clay with heptane caused the hydraulic conductivity to drop to practically zero because of surface tension effects at the water-heptane interface. There appeared to be a threshold hydraulic gradient below which the hydraulic conductivity to heptane was zero. The results of this study show order-of-magnitude differences in hydraulic conductivity depending on testing apparatus and procedures.

Linear stability of fluid flow down a porous inclined plane

Abstract: We investigate the linear stability of a fluid flowing down an inclined permeable plane by studying the evolution in time of infinitesimal disturbances of long wavelength. We assume that the flow through the porous medium is governed by Darcy's law, and determine the critical conditions for the onset of instability in the case when the characteristic length scale of the pore space is much smaller than the depth of the fluid layer above. The results reveal that increasing the permeability of the inclined plane destabilizes the flow of the fluid layer flowing above.