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Showing papers on "Permeability (earth sciences) published in 1976"


Journal ArticleDOI
TL;DR: In this article, the effective diffusion constant and the Darcy's constant of a randomly imbedded sphere model are obtained by a new variational formulation, expressed in terms of the three two-point correlation functions, surface-surface, surface void and void-void correlations.
Abstract: Accurate bounds for the effective diffusion constant and for the permeability (Darcy's constant) of the porous media are obtained by a new variational formulation. These bounds are expressed in terms of the three two-point correlation functions, surface-surface, surface-void and void-void correlations. The results are applied to a randomly imbedded sphere model, and are found to agree well with the previous bound expressed by the three-point correlation functions.

90 citations


Journal ArticleDOI
TL;DR: In this paper, high-pressure laboratory experiments have been performed in which permeability and pore-volume changes were measured during hydrostatic and triaxial deformation of Ottawa sand.
Abstract: High-pressure laboratory experiments have been performed in which permeability and pore-volume changes were measured during hydrostatic and triaxial deformation of Ottawa sand. Under hydrostatic compression, the permeability and porosity of the Ottawa sand initially decreased fairly gradually. At a confining pressure of about 600 bars, however, an abrupt onset of grain crushing and pore collapse resulted in accelerated compaction and permeability loss. In the triaxial-deformation experiments, considerable grain crushing accompanied deformation and both large decreases in pore volume and extremely large decreases in permeability occurred. At higher confining pressures, even though relatively less pore-volume decrease accompanied deformation, there was greater permeability ecrease with axial strain. Dilatancy, or an increase in pore volume with deformation, occurred near the maximum in the stress-strain curves. This dilatancy preceded failure, apparently continued uniformly into the post-failure region, and resulted in a lessened rate of permeability decrease with strain. Comparison of the permeability changes in Ottawa sand in compression and extension showed that if granular material has been subjected to sufficient deformation, fluid flow can be quite anisotropic, the permeability in the direction of maximum compression being significantly lower than the permeability normal to that direction.

76 citations





Journal ArticleDOI
TL;DR: An asymptotic method of solution is developed for a simplified problem in order to establish techniques applicable to the general case and the results are used to discuss some specific examples of physiological interest.

48 citations


Patent
26 May 1976
TL;DR: In this article, a method of manufacturing a high permeability granular material, which is advantageously useful in hydraulic fracturing operations for completing new wells or stimulating older wells which produce oil, gas or other fluids by appropriate sizing and mixing of natural or manufactured particles in a manner such that the material will, when used in a proppant layer, retain its permeability with respect to contacting or surrounding natural soils or geologic formations containing fines capable of plugging conventional permeable materials, when such fines are moved by gravity or fluid flow forces.
Abstract: A method of manufacturing a high permeability granular material, which is advantageously useful in hydraulic fracturing operations for completing new wells or stimulating older wells which produce oil, gas or other fluids by appropriate sizing and mixing of natural or manufactured particles in a manner such that the material will, when used in a proppant layer, retain its permeability with respect to contacting or surrounding natural soils or geologic formations containing fines capable of plugging conventional permeable materials, when such fines are moved by gravity or fluid flow forces.

40 citations


Journal ArticleDOI
TL;DR: The resistivity method has proved to be very suitable in determining the distribution of fresh and saline groundwater in sedimentary deposits as occur in the Netherlands as discussed by the authors, however, the method gives no information about recharge, groundwater flow, geohydrological constants (permeability, transmissibility and hydraulic resistance) and the presence of relatively thin layers of bad hydraulic conductivity.

35 citations



Journal ArticleDOI
Darsh T. Wasan1, B.H. Kaye1, W. Wnek1, R. Davies1, M. Jackson1 
TL;DR: In this article, a cell model for a randomly packed bed of granular particles is developed that takes into account the tortuosity and variations in the cross-sectional area of the cells.

19 citations





01 Jul 1976
TL;DR: Two 3-km-deep boreholes have been hydraulically fractured to establish a flow connection as discussed by the authors, and in situ measurements of permeability show an extremely strong dependence upon pore pressure, the permeability increased by a factor of 80 as the pressure was increased 83 bars (1200 psi).
Abstract: Two, 3-km-deep boreholes have been drilled into hot (approximately 200/sup 0/C) graphite in northern New Mexico in order to extract geothermal energy from hot dry rock Both boreholes were hydraulically fractured to establish a flow connection Presently this connection has a large flow impedance which may be improved with further stimulation Fracture-to-borehole intersection locations and in situ thermal conductivity were determined from flowing temperature logs In situ measurements of permeability show an extremely strong dependence upon pore pressure--the permeability increased by a factor of 80 as the pressure was increased 83 bars (1200 psi) An estimate of the minimum horizontal earth stress was derived from fracture extension pressures and found to be one-half the overburden stress





Patent
Thomas F. Moore1
20 Dec 1976
TL;DR: In this paper, an improved method for the solution mining of a mineral from a subterranean formation was proposed, where an injection well was placed in one zone of high permeability and a production well in the other zone of low permeability both above and below it.
Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of a mineral via solution mining with an injection and production well from a subterranean formation which contains the mineral in a zone of low permeability having a zone of higher permeability both above and below it. The improvement comprises locating an injection well in one zone of high permeability and a production well in the other zone of high permeability.



Journal ArticleDOI
TL;DR: In this article, the authors used 1.5 atm water on never-dried/saturated and on previously-saturated/resaturated specimens, and 2.5 nitrogen gas at mean pressure of 2.1 atm and at infinite pressure.
Abstract: The permeabilities of sapwood and heartwood of twelve species representing different kinds of wood were determined using 1. water on never-dried/saturated and on previously-dried/resaturated specimens, and 2. nitrogen gas at mean pressure of 2.5 atm and at infinite pressure. Also, their effective permeabilities to water were determined. These specimens were subsequently treated with copper Sulfate, and their matched specimens with creosote. The sapwood showed much higher mean permeability and treatability values than the heartwood. The permeability to water was found to be much higher with specimens which had been previouslydried/resaturated than with those which had not been dried. High degrees of correlation between various permeability and treatability values were obtained. When the relationship between permeability and treatability was analysed by species group, higher correlations were obtained in the hardwoods than in the softwoods. Among the hardwoods, the semi-ring porous woods show no correlation, probably because they were all moderately permeable.

Journal Article
TL;DR: The first technique to be tested in the field was electrolinking, or electrocarbonization, accomplished by passing high voltage electricity through the oil shale, but no open fractures were obtained as discussed by the authors.
Abstract: Because oil shale is a rock with little or no permeability, it must be fractured or broken to allow the passage of fluids needed for retorting by in situ methods. The Laramie Energy Research Center has investigated a number of fracturing techniques. The first technique to be tested in the field was electrolinking, or electrocarbonization, accomplished by passing high voltage electricity through the oil shale. In the field under overburden pressure, the shale was carbonized by the electricity and small increases in permeability were noted, but no open fractures were obtained. Hydraulic fracturing has also been tested and in many cases results in increasing permeability, but retorting through hydraulic fractures would be extremely difficult because of the low surface area that results from the fracturing. To increase the surface area a number of different explosives and explosive fracturing techniques have also been investigated. Desensitized nitroglycerin displaced into a naturally occurring porous zone and into a sand-propped hydraulic fracture was used in one experiment. In another experiment slurried explosives were detonated in sand-propped horizontal hydraulic fractures. In this experiment, which is still in progress, preliminary evaluation shows the presence of both vertical and horizontal cracks intersecting the wellbores.



01 Oct 1976
TL;DR: In this article, the use of transient gas reservoir simulation techniques for the purpose of evaluating fracture geometry in two different types of formations is described, where extensive efforts were made to determine fracture length and reservoir permeability by history matching well pressure tests for one well in a sandstone formation and one well from the Devonian Shale formation.
Abstract: The use of transient gas reservoir simulation techniques for the purpose of evaluating fracture geometry in two different types of formations is described. Extensive efforts were made to determine fracture length and reservoir permeability by history matching well pressure tests for one well in a sandstone formation and one well in the Devonian Shale formation. In both cases all available information was used regarding fluid and formation properties. For each of these wells field data were available which consisted of both well test and production performance. In the sandstone well it was also desired to determine why the wells initial production during drilling operations (approximately 7 MMSCFD) decreased after an extensive hydraulic fracturing operation. Different combinations of grid-block sizes and different fracture representations were used in an effort to characterize the permeabiity distribution and fracture extent. Two different combinations of fracture lengths and formation permeability distributions were found to reasonably match the well pressure history. The high initial productivity was explained by the fact that a high permeability zone (5-10 md) had to be used in an unfractured zone to match the well test performance. It is concluded that numerical simulation can be a valuable tool in evaluating the criticalmore » parameters in low permeability stimulated gas reservoirs. Moreover, simulation can be used whenever well test data are not amenable to conventional or type-curve analysis. Finally, by observing if the parameters determined from the well test match also give good agreement when simulating the production history, an extraordinary level of confidence can be placed in the results.« less

Journal ArticleDOI
TL;DR: In this article, the main aspects of aquifers are examined from the view point of hydraulic engineering, aiming to point out which are the parameters related to the exploitation and protection of underground water resources.

Journal ArticleDOI
TL;DR: In this article, a gamma-ray (GK)-sonie (Δt) cross-plot was used to calculate porosity in the Cooper Basin, showing good agreement with core values of porosity.
Abstract: Because of the limited yet adequate logging program run in Cooper Basin wells, porosity has been the most difficult parameter to calculate on a zone-by-zone basis. Empirically derived porosities from a gamma-ray (GK)-sonie (Δt) cross-plot show good agreement with core values of porosity. Furthermore shale percentages calculated from these porosities are in good agreement with shale values derived from crossplot techniques involving sonic, density and neutron log response parameters. An approximation of permeability may also be derived from a further simplified chart.

01 Jan 1976
TL;DR: In this article, the authors compared the variance of flexible contact lens materials to gas permeability at normal atmospheric pressure relative to state of hydration, and found that flexible materials are more permeable to gas than rigid materials.
Abstract: Comparative analysis of variance of several flexible contact lens materials to gas permeability at normal atmospheric pressure relative to state of hydration