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Showing papers on "Permeability (earth sciences) published in 1968"


Journal ArticleDOI
TL;DR: In this article, the authors measured the porosity of Westerly granite as a function of effective pressure to 4 kb and found that porosity is correlated with the electrical resistivity of the granite.
Abstract: The permeability of Westerly granite was measured as a function of effective pressure to 4 kb. A transient method was used, in which the decay of a small incremental change of pressure was observed; decay characteristics, when combined with dimensions of the sample and compressibility and viscosity of the fluid (water or argon) yielded permeability, k. k of the granite ranged from 350 nd (nanodarcy = 10−17 cm2) at 100-bar pressure to 4 nd at 4000 bars. Based on linear decay characteristics, Darcy's law apparently held even at this lowest value. Both k and electrical resistivity, ρs, of Westerly granite vary markedly with pressure, and the two are closely related by k = Cρs−1.5±0.1, where C is a constant. With this relationship, an extrapolated value of k at 10-kb pressure would be about 0.5 nd. This value is roughly equivalent to flow rates involved in solute diffusion but is still a great deal more rapid than volume diffusion. Measured permeability and porosity enable hydraulic radius and, hence, the shape of pore spaces in the granite to be estimated. The shapes (flat slits at low pressure, equidimensional pores at high pressure) are consistent with those deduced from elastic characteristics of the rock. From the strong dependence of k on effective pressure, rocks subject to high pore pressure will probably be relatively permeable.

1,433 citations


Journal ArticleDOI
TL;DR: In this paper, a relation between residual nonwetting-phase saturations and initial non-wetting pbase saturations is derived from published data, which is used in conrzection with established theory relating re?at ive permeabiiit y to pore-size distribution.
Abstract: Relative permeability /urrctiovs are developed {or both twoarrdthrec.phase systems with tfie satr.:ation changes in the imbibition direction. An empiricul relation between residual nonwetting-phase safura. tion ajter water imbibition and initial nonwetting pbase saturations is /ound from pu.blishcd data. Fro7n this empirical relation, expressions are obtained /or trapped and mobile nonwetting-pb(~.se saturations which are used in conrzection with established theory relating re?at ive permeabiiit y to pore-size distribution. Tbe resulting equations yield relative permeability as a /unction o/ saturation having characteristics beiieved to be representative of real systems, Tbe relative permeability o/ water wet rocks for both twoand three pbuse systems, with the saturation cba,nge in the irnbibit ion direction, may be obtained by tijis method after properly selecting two rock properties: the residual nonwe tt ing-phase sat urvrtion aiter tbe complete imbibition cycle, and the cap illary pressure curve.

729 citations



Journal ArticleDOI
TL;DR: In this paper, a variety of crystalline silicate rocks of low porosity (0·001-0·03) were fractured in triaxial experiments at strain rates from about 10−3 to 10−1 sec−1.

317 citations



Journal ArticleDOI
TL;DR: In this paper, the authors considered the problem of air-layer lubrication for Blackhawk-type landslides and suggested that a sufficiently small rate of air loss by leakage through a typical Blackhawk type landslide must be less than about 1 darcy, a value that is reasonable for extremely poorly sorted debris involved.
Abstract: Air-layer lubrication, that is, nearly frictionless support on a layer of trapped and compressed air, has been suggested for the Blackhawk-type landslides and for some nuees ardentes, snow avalanches, and cratering fallback. To ensure a sufficiently small rate of air loss by leakage through a typical Blackhawk-type landslide, the harmonic mean permeability must be less than about 1 darcy, a value that is reasonable for the extremely poorly sorted debris involved. A further necessary requirement for air-layer lubrication to occur, rather than simultaneous deposition and fluidization, is that the product of the permeability and the bulk density of the basal debris be less than 0.7 times the product of the harmonic mean permeability and the arithmetic mean density for the debris as a whole, as is probably in fact the case in these landslides.

156 citations



Journal ArticleDOI
TL;DR: In this paper, the authors examined the mechanical properties of the heated marble and showed that they are different from those of soils, and that a small amount of confining pressure varies the triaxial strength rapidly, the initial slope of the Mohr envelope being of the order of 65° and the strength finally increasing to over 80% of that of the original rock.
Abstract: Synopsis If coarse grained marble is heated to around 6OO°C the anisotropy of thermal expansion of calcite causes almost complete separation at grain boundaries. The resulting material retains its shape and consists of a mass of crystals in contact, with a porosity of about 4%, very small direct tensile strength and the mechanical analysis and permeability to water of a sand. It may be regarded as a laboratory model of randomly jointed rock and perhaps of bad and broken rock in general. It has frequently been suggested that soil mechanics theory may be applied to such rock. This Paper examines the mechanical properties of the heated marble and shows that they different from those of soils. A small amount of confining pressure varies the triaxial strength rapidly, the initial slope of the Mohr envelope being of the order of 65° and the strength finally increasing to over 80% of that of the original rock. Young's modulus also increases with confining pressure but only to about 30% of that of original rock. ...

67 citations


Journal ArticleDOI
TL;DR: In this article, an equation for the permeability of a porous medium based on the general principles of the series-parallel model contains a double integral which is solved for several continuous probability laws describing the distribution of the sizes of the interstices of the porous medium.
Abstract: An equation derived for the permeability of a porous medium based on the general principles of the series-parallel model contains a double integral which is solved for several continuous probability laws describing the distribution of the sizes of the interstices of the porous medium. The agreement between calculated results and available experimental data is satisfactory.

58 citations






Journal ArticleDOI
TL;DR: In this article, an equation is presented for calculating saturated permeability from capillary pressure-desaturation data, along with the relative permeability equations of Brooks and Corey is proposed for calculating the permeability of both saturated and partially saturated media.
Abstract: An equation is presented for calculating saturated permeability from capillary pressure-desaturation data. The use of this equation along with the relative permeability equations of Brooks and Corey is proposed for calculating the permeability of both saturated and partially saturated media. The analysis leading to the development of the equation is based on theory developed in the petroleum industry. The equation utilizes parameters introduced by Brooks and Corey for describing the hydraulic behavior of partially saturated porous media on the drainage cycle. In laboratory measurements, the permeability of three disturbed soils each packed at five different values of porosity was determined at various capillary pressures. Predicted relationships were calculated using capillary pressure-desaturation data in the new equation and in the relative permeability equations of Brooks and Corey. Calculated and experimental values of permeability agreed within 27% over the range of capillary pressures studied.

Journal ArticleDOI
TL;DR: In this article, the efficiency of drainage layers to accelerate consolidation of clay fill embankments is considered and the influence of such factors as layer thickness, length and permeability is examin...
Abstract: Synopsis The efficiency of drainage layers to accelerate consolidation of clay fill embankments is considered and the influence of such factors as layer thickness, length and permeability is examin...

Journal ArticleDOI
TL;DR: In this article, the authors derived bounds on the permeability of a porous medium to Knudsen flow by applying the variational procedure of DeMarcus, expressed in terms of certain averages characterizing the random pore geometry.
Abstract: Rigorous bounds on the permeability of a porous medium to Knudsen flow are formulated by applying the variational procedure of DeMarcus. The bounds are expressed in terms of certain averages characterizing the random‐pore geometry. Explicit calculations are given for a model pore structure generated from randomly overlapped spheres.


Journal ArticleDOI
TL;DR: In this paper, a mathematical definition of permeability for orthotropic porous mediums is developed from the assumption that these mediums obey Darcy's Law in the three directions normal to the planes of symmetry.
Abstract: The mathematical definition of permeability for orthotropic porous mediums is developed from the assumption that orthotropic porous mediums (i.e., porous mediums that possess three mutually perpendicular planes of structural symmetry) obey Darcy's Law in the three directions normal to the planes of symmetry. This assumption is shown to lead to the conclusion that permeability obeys the transformation law definitive of second-order tensors; and that consequently a permeability quadric, the Mohr circle representation of transformation of permeability components and permeability invariants, can be defined.


Journal ArticleDOI
01 Dec 1968-Vacuum
TL;DR: In this article, the authors measured the permeability of a porous material by measuring with a flowmeter the amount of gas flowing through it under an absolute pressure gradient, and the same has been done with model materials.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the intrinsic permeability of hydrological porous mediums and found that in certain cases the permeability itself varies with tem- perature and is not constant, as was previously assumed.
Abstract: Experiments designed to measure the intrinsic permeability of hydrological porous mediums have shown that in certain cases the permeability itself varies with tem- perature and is not constant, as was previously assumed. For cemented quartz mediums permeabilities were found to vary by as much as 0.5% per degree C over the temperature span (20-60oC) reported in this experimental study. Similar measurements with vitrified mediums showed no appreciable temperature coefficient of permeability. As a by-product of the investigation a characteristic length parameter, in terms of the laminar (permeability) and inertial flow coefficients, has been used to define a modified Reynolds number for all porous mediums. This length parameter appears to be directly proportional to the mean pore dimension as determined from porosimetry measurements. The data obtained from all samples have been found to correlate well in graphical form and are presented in a generalized friction

Journal ArticleDOI
TL;DR: In this article, the authors illustrate the use of multi-dimensional, 2-phase, compressible fluid flow calculations to simulate the depletion of an aquifer storage reservoir is dependent upon reservoir heterogeneity, aquifer strength, production rate and fluid and rock properties such as density, viscosity, relative permeability, capillary pressure and residual gas saturation.
Abstract: The recovery of cushion gas upon ultimate depletion of an aquifer storage reservoir is dependent upon reservoir heterogeneity, aquifer strength, production rate and fluid and rock properties such as density, viscosity, relative permeability, capillary pressure, and residual gas saturation. This study illustrates the use of multi-dimensional, 2-phase, compressible fluid flow calculations to simulate the depletion. Results which illustrate the non-exhaustive examination of the effects of heterogeneity, aquifer strength, and gas production rate are presented. The study indicates a strong dependence of recovery upon reservoir heterogeneity. The multi- dimensional type of calculation employed appears necessary to reliably estimate recoverable cushion gas for any particular reservoir.

Journal ArticleDOI
TL;DR: Montmorillonite clays in amounts above 3% by weight may be expected to reduce effective permeability of pure sands to fresh water by 100% or to practically zero for sands with the grain size distribution with mean of 0.30 mm and standard deviation of 018 mm as discussed by the authors.
Abstract: Montmorillonite clays in amounts above 3% by weight may be expected to reduce effective permeability of pure sands to fresh water by 100% or to practically zero for sands with the grain size distribution with mean of 0.30 mm and standard deviation of 0.18 mm. Kaolinite clays in amounts above 16% by weight may be expected to reduce the permeability of similar sands to practically zero.


Journal ArticleDOI
TL;DR: In this article, a plot of porosity against permeability, reveals two distinct trends; non-sheared samples are more representative of intergranular flow whilst sheared samples reflect fissure-controlled hydraulic conductivity.

Patent
Arthur H Youmans1
17 Jan 1968
TL;DR: In this article, a system for the measurement of permeability of subsurface formations in situ injecting a neutron absorber fluid and observing the progressive change in the thermal neutron absorption cross section is presented.
Abstract: This system permits the measurement of permeability of subsurface formations in situ injecting a neutron absorber fluid and observing the progressive change in the thermal neutron absorption cross section.

Journal ArticleDOI
TL;DR: In this article, the porosity and permeability characteristics of carbonate reservoirs are evaluated using a detailed sample study, and a method of qualitative and quantitative logging is suggested to identify porosity fabrics.
Abstract: Detailed sample studies are necessary to evaluate the porosity and permeability characteristics of carbonate reservoirs. Depositional porosity fabrics and the resultant permeability are varied, and may range from highly porous impermeable chalk to less porous but more permeable intergranular porosity in carbonate banks, which may be composed of pellets, oolites, or admixtures of fragmental debris. The presence of fossil cavities, calcispheres, and reefoid deposits may modify the overall fabric. In addition to these depositional characteristics, tectonism can alter the basic porosity-permeability relations by means of fracturing, recrystallization, and/or tectonic dolomitization. Several of these types of porosity may be present in a single deposit and influence log analysis in either a negative or positive manner. A nonpermeable chalk or calcisphere porosity carrying high water saturation may produce oil if the fracture fabric or associated intergranular permeability is oil bearing. Conversely, nonproducible oil may be trapped in the high-porosity-low-permeability deposits, and the more permeable fracture or intergranular porosity may be water bearing. These varied porosity fabrics can be recognized by sample and core examination, and a method of qualitative and quantitative logging is suggested. Utilization of well-sample data coordinated with realistic log analysis can lead to successful completion in zones which might be overlooked in a cursory log analysis.


01 Jan 1968
TL;DR: In this article, the authors developed a relationship between the optimum free gas saturation at which to waterflood a reservoir and the properties of the fluids and the rock, which was used to predict the optimum gas saturation.
Abstract: The optimum gas saturation is defined as that free gas saturation needed to achieve maximum oil recovery by waterflooding and primary depletion. This paper presents an investigation to develop a relationship between the optimum free gas saturation at which to waterflood a reservoir and the properties of the fluids and the rock. The optimum gas saturations for various rock-fluid systems were obtained from the literature and from previously unpublished sources. Distribution of the rock and fluid systems assures a good representation of reservoirs where the effects of free gas saturation will be most benefical. A multiple regression analysis program written for the IBM 7094 digital computer is used to compare numerous equations and to calculate their coefficients. The final equation containing 4 coefficients results in an average absolute deviation of 4.6% for all the sets of data. The correlation developed is useful to predict the optimum gas saturation at which maximum oil recovery is obtained from variables that normally are measured either in the laboratory or in the field. Finally, an example calculation based on actual reservoir rock and fluid properties is presented. (26 refs.)