Hydraulic rock types

Several Bossier sand hydraulic rock types have also been identified (Newsham Rushing... 

The hydraulic rock type classification provides a physical measure of a rock s flow and storage properties at current conditions. When described on the basis of the dominant pore throat diameter determined from high-pressure mercury capillary pressure data, distinct groupings of rocks having similar flow and storage properties, i.e. hydraulic rock types, are... 

Fig. 12. Incremental mercury intrusion plot used to identify hydraulic rock types for the Bossier sands, Dew/Mimms Creek Fields.

Fig. 13. Range of effective porosity and absolute permeability for Bossier sand hydraulic rock types, Dew/Mimms Creek Fields (Winland 1972).

Many rock types have a layered structure, individual rock layers varying in thickness from a few centimeters to tens of meters. Layered rocks include marine sediments, most continental sediments, lava flows and volcanic ejecta, and intrusive sills. The hydraulic properties vary from one rock layer to another, often resulting in abrupt changes along the vertical axis. In terms of the permeability coefficient (k) the lateral coefficient (kx) may significantly differ from the vertical coefficient (kz). The alternation of aquifers and aquicludes results from the layered structure of different rocks, and the occurrence of springs is often controlled by the layering of rocks. Fissures may be restricted to individual rock layers or cross several rock beds, in which case water flow is improved, mainly in the vertical direction. 

Data for characterisation of faults in the subsurface are limited to two sources, seismics and wells. Seismic reflection data allow the displacement distribution over a fault surface to be mapped while well and core data may allow determination of fault rock types and deformation mechanisms at specific points, in addition to characterising the lithologies of the host sequence. It is evident from outcrop studies that the internal geometries of fault zones are usually complex, in terms of the numbers of individual slip surfaces, the partitioning of slip between them and in the distribution of different fault rocks, all of which vary over a fault surface. This 3-D complexity of fault zone structure may not be apparent from either seismic or core data but is nevertheless crucial to the bulk hydraulic properties of a fault. 

Abstract The well-known features of the Earth s crust are interpreted as the result of rock fracturing under deep thermodynamic conditions. For this aim, triaxial failure data are scaled up to the crust taking into account temperatures and rock types. The critical depth of hydraulically permeable cracks coincides with the Mohorovicic boundary and that relates to the crust genesis. The annihilation of a crack system at this depth is in accordance with seismic velocity jump known from geophysical exploration. The features of crust floors as well as total thickness, fault inclination, etc, are explained by the suggested mechanical approach. 

A convenient way to define the coefficient of permeability, in order to compare its value for different types of rocks, is to determine its empirical value for hydraulic gradients of 45°, that is, for Ah/Al=l. In such cases k=V. 

Figure 1.1 Ranges of permeabilities and hydraulic conductivities for different types of rock (modified after R. Allan Freeze and John A. Cherry. GROUNDWATER, 1979, p. 29. Reprinted by permission of Prentice Hall, Englewood Cliffs, New Jersey).

For various aquifer minerals, porosity varies over a fairly narrow range (ca. 0.3 to 0.5) but hydraulic conductivity varies over many orders of magnitude.2 Even for a specific type of aquifer material, ranges of 1-4 orders of magnitude are common (e.g., 10 8 5 to 10 4 m/s for fractured rock, 10-5 to 10 3 m/s for well-sorted sand). The lowest hydraulic conductivities are found for crystalline rock (10 14 to 10 10 m/s) and the highest for well-sorted gravel (10-2 to 1 m/s) and clean sand or cavernous limestone (10 6 to 10 2 m/s). 

Hydraulic tests were conducted at 356-m depth on a single fracture intersecting a 500-m deep borehole in crystalline rock at the Rock Mechanics Laboratory of Lulea University of Technology in Sweden. Three types of hydraulic tests were included (i) pulse test. 

Based on store condition of coal seam and survey results and tests of joints surface in Xiezhuang mine, rock mass structure types are analyzed, and rock mass quality is quantificationally evaluated. The conclusion shows that engineering geological conditions of the working face roof belong to medium. Allowable hydraulic radius are calculated... 

The work undertaken by a river is threefold, it erodes soils and rocks and transports the products thereof, which it eventually deposits (Fig. 3.19). Erosion occurs when the force provided by the river flow exceeds the resistance of the material over which it runs. The velocity needed to initiate movement, that is. the erosional velocity, is appreciably higher than that required to maintain movement. Four types of fluvial erosion have been distinguished, namely, hydraulic action, attrition, corrasion and corrosion. Hydraulic action is the force of the water itself. Attrition is the disintegration that occurs when two or more particles that are suspended in water collide. Corrasion is the abrasive action of the load carried by a river on its channel. Most of the erosion done by a river is attributable to corrasive action. Hence, a river carrying coarse, resistant, angular rock debris possesses a greater ability to erode than does one transporting fine particles in suspension. Corrosion is the solvent action of river water. 

During the course of construction, watch out for flying debris of all types including sparks, metal scraps, hydraulic fluid, and rocks. 

The granite used in the current study was obtained from the Lingyan Mountain, located in Suzhou City, Jiangsu Province, China. The rock was sliced and polished into the cubic specimens with the size of around 50 mm x 50 mm x 50 mm. The uniaxial compression tests for the specimens were employed using the YE-2000 type of hydraulic machine, produced by the Zhejiang Jingyuan Machinery Company Limited, China. The distances from the camera to the specimens were about 5.0 m. The video camera was placed normal to the rock specimen surface in order to eliminate the perspective errors and lens distortion. 

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