Permeability, hydraulic

Hydraulic Permeability Hydraulic permeation of water through the membrane occurs as a result of a pressure difference between the anode and cathode. The molar flow rate of water from the cathode to the anode can be written from Darcy s law ... 

Principal Option for Containment/ Recovery Excavation Vacuum extraction Temporary cap/cover Hydraulic modification No action Groundwater pumping Subsurface drains Hydraulic barriers Low permeability barriers No action Overflow/underflow containment (i.e. oil booms) Run off/run on control Diversion/collection No action Capping/ nsulation Operations modifications Gas collection/removal No action... 

Hydraulic gradient, permeability, and effective porosity from water level contours, pump test results, and laboratory analyses... 

Structure of the medium. It is temperature-dependent, since the properties of the fluid (density and viscosity) are temperature-dependent. Hydraulic conductivity can be written more specifically in terms of the intrinsic permeability and the properties of the fluid. 

The permeability relative to a pure liquid, usually water, may be determined with the help of different devices that operate on the principle of measurement of filtrate volume obtained over a definite time interval at known pressure drop and filtration area. The permeability is usually expressed in terms of the hydraulic resistance of the filter medium. This value is found from ... 

Atterberg-limit tests determine the water content influence in defining liquid, plastic, semisolid and solid states of fine-grained soils. Permeability tests may be carried out in the laboratory or in the field. Such tests are used to determine the hydraulic conductivity coefficient k. ... 

Low-pressure squeeze cementing operations are utilized where the existing permeability structure is sufficient to allow the cement slurry to efficiently move in formation without making new fracture surfaces with the hydraulic pressure. 

Hydroxypropylguar gum gel can be crosslinked with borates [1227], ti-tanates, or zirconates. Borate-crosslinked fluids and linear hydroxyethyl-cellulose gels are the most commonly used fluids for high-permeability fracture treatments. This is for use for hydraulic fracturing fluid under high-temperature and high-shear stress. 

A low-molecular-weight condensation product of hydroxyacetic acid with itself or compounds containing other hydroxy acid, carboxylic acid, or hydroxy-carboxylic acid moieties has been suggested as a fluid loss additive [164]. Production methods of the polymer have been described. The reaction products are ground to 0.1 to 1500 p particle size. The condensation product can be used as a fluid loss material in a hydraulic fracturing process in which the fracturing fluid comprises a hydrolyzable, aqueous gel. The hydroxyacetic acid condensation product hydrolyzes at formation conditions to provide hydroxyacetic acid, which breaks the aqueous gel autocatalytically and eventually provides the restored formation permeability without the need for the separate addition of a gel breaker [315-317,329]. 

Addition of rubber particles of 30% to 100% by weight to cement with a grain size of approximately 40 to 60 mesh (0.4 to 0.25 mm) will produce a lightweight cement. The addition of rubber particles also creates a low permeability. The compositions are advantageous for cementing zones subjected to extreme dynamic stresses such as perforation zones and the junctions of branches in a multi-sidetrack well. Recycled, expanded polystyrene lowers the density of a hydraulic cement formulation and is an environmentally friendly solution for downcycling waste materials. 

Hydraulic fracturing is a technique to stimulate the productivity of a well. A hydraulic fracture is a superimposed structure that remains undisturbed outside the fracture. Thus the effective permeability of a reservoir remains unchanged by this process. The increased productivity results from increased wellbore radius, because in the course of hydraulic fracturing, a large contact surface between the well and the reservoir is created. 

The formation of calcium carbonate (CaCOs), calcium sulfate, and barium sulfate scales in brine may create problems with permeability. Therefore it is advantageous that newly made fractures have a scale inhibitor in place in the fracture to help prevent the formation of scale. Formulations of hydraulic fracturing fluids containing a scale inhibitor have been described in the literature [1828]. 

R. C. Navarrete and J. P. Mitchell. Fluid-loss control for high-permeability rocks in hydraulic fracturing under realistic shear conditions. In Proceedings Volume, pages 579-591. SPE Prod Oper Symp (Oklahoma City, OK, 412-414), 1995. 

The most important parameter is the permeability (or hydraulic conductivity) is defined as the resistance for water to flow in the aquifer material and it is expressed as a flow rate (m/s) when it is affected by the gravity (gradient 1.0). 

It is obvious from Equation 14.14 that the most important parameter determining the volumetric air flow rate <2W is the intrinsic permeability K of soil. At this point it is important to stress the difference between water permeability (or hydraulic conductivity) k , air permeability ka, and intrinsic permeability K. In most cases, when permeability data are provided for a type of soil or geological formation, these data are based on hydraulic conductivity measurements and describe how easily the water can flow through this formation. However, the flow characteristic of a fluid depends greatly on its properties, e.g., density p and viscosity p. Equation 14.16 describes the relationship between permeability coefficient k and fluid properties p and p ... 

The airflow equations presented above are based on the assumption that the soil is a spatially homogeneous porous medium with constant intrinsic permeability. However, in most sites, the vadose zone is heterogeneous. For this reason, design calculations are rarely based on previous hydraulic conductivity measurements. One of the objectives of preliminary field testing is to collect data for the reliable estimation of permeability in the contaminated zone. The field tests include measurements of air flow rates at the extraction well, which are combined with the vacuum monitoring data at several distances to obtain a more accurate estimation of air permeability at the particular site. 

Hydraulic conductivity is one of the characteristic properties of a soil relating to water flow. The movement of water in soil depends on the soil structure, in particular its porosity and pore size distribution. A soil containing more void space usually has a higher permeability. Most consolidated bedrocks are low in permeability. However, rock fractures could create a path for water movement. 

Other factors affecting performance include the presence of toxic material, the redox potential, salinity of the groundwater, light intensity, hydraulic conductivity of the soil, and osmotic potential. The rate of biological treatment is higher for more permeable soils or aquifers. Bioremediation is not applicable to soils with very low permeability, because it would take a long time for the cleanup process unless many more wells were installed, thus raising the cost. 

Bioremediation difficult to implement in low-permeability aquifers (hydraulic conductivity <10 4 cm/s). 

Hydraulic and geologic parameters, such as hydraulic conductivity, hydraulic gradient, and permeability, that will affect the migration and dissolution of the oxidant once it is introduced to the subsurface. 

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