Magnetic pore fabric analysis: a rapid method for estimating permeability anisotropy

PROPERTIES:PERMEABILITY & CAPILLARITY some fundamental problems. Other issues such as anisotropy, nonlinearity, and in particular, aspects of the role of pore fluid on rock strength and failure mechanism, are briefly addressed. -from Authors 943135 Computational methods in fluid flow D. Elsworth, in: Comprehensive rock engineering. Vol. 2, ed J.A. Hudson, (Pergamon), 1993, pp 173-189. Powerful computational techniques are available for the analysis of coupled flow deformation and transportproblems. Domain methods are capable of accommodating irregular and heterogeneous geo|ogical bodies represented by complex constitutive models. Finite element methods represent the most powerful domain based method where tensoral quantities such as stresses and deformations are to be included. Depending on theparticular geological system or process, some aspects of the coupling between comting processes may be either weakly present or absent. either case a reduced set of equations describing the system will suffice. The form of the equation set may be determined from the maximum set following deletion of the absent coupling and used to advantage. -from Author

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943136 Rock mechanics in the 1990s: rock mechanics in reservoir engineering ed B. C. Haimson, International Journal o f Rock Mechanics and Mining Sciences, 30(7), 1993, pp 1185-1229. These p.apers were originally presented at the 34th US Sympnsxum on Rock Mechanics, June 1993. Eight papers are included in this section examining: naturally fractured reservoir modelling; numerical simulation of shear-induced compaction; shale pore pressure change due to drilling fluidsalinity; compaction and pore pressure change in the North Sea;,overpressuring, fluid flow and stress regimes in the Jean d A r c B a s i n , Canada; dynamic confinement during drilling in pressured boreholes; surface displacement inversion for in situ process monitoring; and permeability reduction as a result of grain crushing. -R.Gower 943137 Rock mechanics in the 1990s: coupled mechanical and hydrologic processes ed B. C. Haimson, International Journal o f Rock Mechanics and Mining Sciences, 30(7), 1993, pp 1119-1184. These papers were originally presented at the 34th US Symposium on Rock Mechanics, June 1993. Elevenpapers deal with various aspects of stress effect on the hydraulic properties of various rock types. Hydraulic fracture, pore pressure buildup, porous rock compressibility and waste containment properties of fractured anhydrite axe amongst the topics covered. -R.Gower 943138 Short-term and long-term permeabilities of contaminated clays N. J. Meegoda & R. A. Rajapakse, Journal o f Environmental Engineering - ASCE, 119(4), 1993, pp 725-743. Under short-term and simulated long-term exposures of water-soluble chemicals to soils, the changes in hydraulic conductivities of laboratory consolidated clays are measured and reported. The permeability tests are performed using the both flexi-wall and modified fixed-wall permeameters produced similar results. The short-term permeability tests showed a change in hydraulic conductivity values but not the intrinsic permeabilities of soils. The simulated long-term exposure of organic chemicals to soils showed a change in the soft structure and an increase in the intrinsic permeability of soils. The increasing trend in the intrinsic permeability of a given soil was weakly correlated to the decreasing dielectric constant of the pore fluid. -from Authors 943139 Feasibility of ultrasonic enhancement of flow in clayey sands L. Reddi, S. Berliner I I I & K. Y. Lee, Journal o f Environmental Engineering - ASCE, 119(4), 1993, pp 746-752. Results are presented from a series of laboratory experiments involving the enhancement of hydraulic conductivity of clayey sands using ultrasonic excitation. The

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enhancement of hydraulic conductivity was found to be inversely proportional to the density of the soil. Grain-size distribution analyses of the soils conducted before and after ultrasonic treatment indicated that particles smaller than 0.04 mm were mobilized by ultrasonics, and that particles in the size range of 0.04 mm to 1 mm were subjected to fracturing. -from Authors 943140 Analysis of piezocone dissipation data using dislocation methods D. Elsworth, Journal o f Geotechnical Engineering ASCE, 119(10), 1993, pp 1601-1623. The theory of a moving point dislocation is applied to the rational determination o f permeability and consolidation coefficients from piezocone-sounding data. Motion of the process zone in following the penetrometer tip is shown to result in important differences in behavior between static and undrained analogs to ~ . netration. Tip pressures are shown to become steady within approximately 1 s following drivage initiation at a standard rate of 2 cm/s. Shaft ressures within 10 radii of the tip eo~uilibrate within 10 s. ostarrest pressure dissipation at the tij> enables consolidation coefficient, c, to be determined independently. Relationships are developed for net cone end bearing as a linear function of elastic parameters and for pore pressure ratio. Pore pressure ratio is shown to be an insensitive index in low c soils. Results from well-documented field investigations in both normally consolidated and overconsolidated materials are used to independently establish the applicability of the proposed parameter determination techtuques. -from Author 943141 Description des ecoulements diphasiques en fracture a I'aide du concept de permeabilite relative (Description of two-phase flow in a f r a c t u r e using the relative permeability concept) M. Fourar & S. Bories, Comptes Rendus - Academic des Sciences, Serie If, 317(11), 1993, pp 1369-1376. Resorting to the relative permeability concept to describe steady-state laminar two-phase flows in a fracture is justified theoretically by using the formalism developed for two-phase flow in pipes. From this approach, theoretical relations are proposed between the relative pormeabillties of phases and saturation. These expressions are experimentally evaluated for a two-phase air-water flow i n a n artificial fracture. There is an abridged English version. -English summary 943142 Evaluation of the hydraulic conductivity of aquitards R. K. Rowe & P. Nadarajah, Canadian Geotechnical Journal, 30(5), 1993, pp 781-800. The evaluation of the bulk vertical hydraulic conductivity of an aquitard based on its response to the pumping of an adjacent aquifer is examined using Biot's theory. Consideration is given to the errors in interpretation of the results of pumping tests which arise as a result of the time lag associated with different t y ~ s of piezometers as well as the length of the piezometer, uactors to allow for correction of these errors axe ipresented. A comparison is made between the results obtained from diffusion theory and the more rigorous Biot's theory. -from Authors 943143 Magnetic pore fabric analysis: a r a p i d method for estimating permeability anisotropy S. Pfleiderer & H. C. Hails, Geophysical Journal International, 116(1), 1994, pp 39-45. The ayerage orientation and fabric anisotropy of interconnected pore spaces in sandstones is derived from magnetic pore faoric analysis, a new technique which measures the anisotropy of magnetic susceptibility (AMS) of samples impregnated with a magnetic suspension. In magnetic pore fabric analysis, the permeable part of the porous network, consisting of pore bodies connected by pore throats, is rendered magnetically susceptible. A M S directly yields the average etongation direcuon of pore bodies and offers a simple way to "investigate the effect of pore-shape anisotropy on petropnysicat parameters such as hydraulic and electrical conductivity. -from Authors