Showing papers on "Permeability (earth sciences) published in 1969"

Preliminary experiments on hydrodynamic movement induced by evaporation and their bearing on the dolomite problem

Abstract: SUMMARY Experiments were performed to demonstrate that saline interstitial waters under an arid coastal plain could be set in hydrodynamic movement to replace the evaporative loss near the surface. In contrast to movement in a vadose zone, which is related to capillary forces caused by surface tension, the type of movement we observed was induced by a vertical hydraulic gradient under the evaporated area. Fluid flow through porous media was induced by an upward decrease in hydrodynamic potential during evaporation. We propose to call this type of movement evaporative pumping. Experiments further verified that flow rate induced by evaporative pumping was directly governed by evaporation alone; linear flow rate through coarse sand and that through very fine silt was approximately the same under the same evaporative condition. Yet the movement apparently obeyed Darcy's law. Since the permeability of the medium was fixed, and the flow rate was dictated by evaporation, only the hydraulic gradient could be the dependent variable in the Darcy equation. We observed that the gradient was indeed much greater in relative impermeable silt than in permeable sand, when the water to replace evaporative loss must flow with the same rate through those media. Our experiments suggested that hydrodynamic movement induced by evaporation could be an effective mechanism to transport magnesium-bearing solutions through relatively impermeable sediments of an arid coastal plain. Computations showed that dolomitization by evaporative pumping could proceed at a rate to account for the origin of Recent dolomite crusts, and for the great thickness of ancient supratidal dolomites. In contrast, we believed that dolomitization by seepage reflux or by groundwaters cannot be extensive, because of the inadequate magnesium-supply rates by such waters.

Porosity and permeability of unconsolidated, upper Miocene sands from grain-size analysis

Abstract: Core analysis data for 78 cores taken from Upper Miocene sands were used to develop correlations between porosity and permeability of unconsolidated cores and their grain-size analyses. The grain-size distributions of these cores are best described mathematically by the Rosin-Rammler equation. The two parameters of this equation together with two other easily measured parameters of grain size were grouped to give correlations with porosity and permeability. Porosities were correlated to within 2 percent for 80 percent of the samples and permeabilities were correlated to within a factor of 2 for 70 percent of the samples.

Breakdown of surface burning of gas-permeable porous systems

Abstract: 1. The breakdown of surface burning of porous secondary and mixed explosives has been studied at low values of the gas permeability (10−3–10−6 darcy) and porosity (0.15–0.03) of the specimens. 2. The causes of diffusion of the combustion products into the pores have been examined. 3. Relations have been obtained between critical pressure and gas permeability, porosity and initial particle size. The breakdown of surface burning is determined not only by the gas permeability but also by the nature of the pore size distribution. 4. Convective burning is initiated and develops in the individual large pores. 5. It has been shown that an increase (up to a certain limit) in the diameter of the porous charge reduces combustion stability. 6. A continuous molten layer formed at the burning surface stabilizes the combustion of gas-permeable porous systems and is a cause of the enhanced combustion stability of secondary explosives. 7. A factor facilitating penetration of combustion into the pores is the small distance from the burning surface to the high-temperature gas zone.

Method of reducing the permeability of a thief zone

Abstract: A method for obtaining a flat injection profile for a fluid, such as a drive fluid used in an oil recovery operation, that is being injected into an interval of earth formation of nonuniform permeability by contacting the most permeable portions of the interval with a slurry containing a mixture of flexible solid fibers and a fiber-bonding agent, such as sodium silicate or a polyepoxide. An agent to precipitate or gel the bonding agent is then injected.

Method for increasing subterranean formation permeability

Abstract: A method for increasing the permeability of an already hydrated clay or shale subterranean formation by at least partially dehydrating at least a portion of the formation by heating or injection of a dehydrating liquid or gas, contacting at least part of the dehydrated portion of the formation with a material which hinders rehydration of the formation and thereafter exposing the formation to water.

Porosity-Permeability Relationship Of Shale

Abstract: Fluid pressure gradients in shales can be determined by the porosity distributios of the incompletly compacted shales. It is possibel, therefore, to estimate permeability changes in shales by using the fluid pressure gradient (derived from the shale porosity distribution) and Darcy's law. The integration of these permeability changes with porosity values in shales can be used to establish a relation between shale porosity and permeability in the subsurface. This method of analysis applied to Cretaceous shales in Alberta and Saskatchewan, Canada, revealed that the decrase of shale permeability with decrease in porosity is less than that given by the Archie's relation, which is based on sandstone and carbonate rocks. This new knowledge ofthe porosity-permeability relation in shales promotes a better understanding og fluid movements in the shales during compaction, which will influence the migration and accumulation of hydrocarbons.

Oznaczanie współczynników filtracji gruntów słaboprzepuszczalnych, półprzepuszczalnych i praktycznie nieprzepuszczalnych

Abstract: DETERMINATION OF PERMEABILITY COEFFICIENTS OR LOW-PERMEABLE, SEMI-PERMEABLE AND PRACTICALLY IMPERMEABLE SOILS Summary Permeability properties of soils are of considerable importance for engineering-geological and hydrogeological estimation of the terrain. They determine the co-operation between the engineering object and building substratum. Determination of values of permeability coefficients is of great significance in the evaluation of filtration conditions in the areas of dam axis and dam abutments, in the beds sealing water basins, in drainage of opencast workings and buildings, as well as in stability of slopes, in processes of deformation of filtration soils, a.o. In the article the author makes an analysis of determination of permeability coefficients of low-permeable, semi-permeable and impermeable soils by means of various methods, drawing proper conclusions that are presented in the final remarks of his paper.

Down-hole permeability prediction – a chemometric wire-line log feasibility study from a North Sea chalk well

Abstract: Permeability in chalk depends primarily on porosity but also on other factors such as clay and quartz content, and can theoretically be described by the Kozeny equation using empirically determined constants (Mortensen et al. 1998; Rogen & Fabricius 2002). Recent attempts to predict permeability from wire-line logs have shown that compressional velocity within operative chalk units, defined by specific surface and hydraulic properties established from stratigraphy and core plugs, can provide excellent well permeability predictions (Alam et al. 2011). High-quality predictions depend on a solid knowledge of a multitude of parameters of the relevant ‘operative rock types’. The more detailed this a priori knowledge is, the better predictions can be achieved. But this approach may, or may not, be fast enough for wellsite operations or when core data are lacking. In this study, we illustrate a situation for direct permeability prediction if only well-site, wire-line logs are available.

Well Capacity for Continuous Permeability Variation

Abstract: The results of an analysis of the relative effects of continuous, radially symmetric permeability variations on the capacity of a single artesian well are graphically presented. Such variations may result from acid treatment, fracturing, effects incident to mud-drilling, or from structural alternations in soil adjacent to a well. The change in permeability was assumed to be maximum at the well face and to decrease exponentially in a radial direction away from the well axis. The resulting equation for relative well capacity was integrated numerically for various cases to yield a family of curves which, together with estimates of the altered and original permeability values and of the radial extent of the permeability change, can be used to quickly obtain estimates of well performance.

Restoring Permeability to Clay-Containing Water Damaged Formations

Abstract: This study shows that Ca/sup + +/ ions used to treat hydrated clays in the expanded state do exchange with the other positive ions, but do not cause the clay to shrink while it is wet. The clay must be dried and shrunk as a result of the drying step. Such a clay will not re-expand to its original expanded size when it is rehydrated. With respect to field applications, this fact indicates that a reservoir damaged by fresh water will show little or no benefit from a treatment with calcium ions as long as the clay remains wet. If the clay can be dried by some means, then it is anticipated that upon exposure to fresh water, the dry calcium-treated clay will not swell to its original size. A possible procedure for field treatment is outlined.

The Permeability of Porous Rocks under High-Pressure

Abstract: Characters of deep reservoir rocks have been studied recently. In this paper the relationship between pressure and permeability, which varies with the kind of gases, was investigated from the experimental and theoretical studies of the permeability of gases through porous rocks under pressure.In this experiment, high-pressure gases such as He, Ar, N2, CH4, C2H6 and C3H8, were forced to flow through rocks, and permeabilities of each gas have been decided.In the discussion of the experimental result, it was confirmed that Klinkenberg's result was obtained under higher pressure if the gas flow was laminar. It was also, confirmed that there was a linear relation between Klinkenberg's Constant and the mean free path of gases.It may well be said that, in the future, permeability of gases can be computed using the permeability data of a certain gas.