Showing papers on "Permeability (earth sciences) published in 1970"

Method for Determining Permeability from Reservoir Rock Properties

Abstract: Porosity and permeability of reservoir sandstones can be related to the primary rock properties of composition, texture, and packing. Permeability is assumed to be largely a function of rectilinear pore size which, in turn, is a function of mean grain size, sorting as expressed by deviation of grain size distribution, mean grain shape, and packing of grains. By means of systematic packings of uniform spherical grains, the size and shape of rectilinear pores can be determined for porosities of 30 to 40 percent. By considering laminar flow of fluids through pores of idealized cross sections, a general equation can be derived in which permeability is a function of the square of the median grain size, of the fifth power of porosity, and of phi percentile deviation. When the equation is applied to clean sands and sandstones of 30 to 40 percent porosity, permeability may be calculated with reasonable accuracy. The agreement between theoretical and measured values suggests that this approach may be applicable to other packings and porosities in subsurface reservoir sandstones.

Simulation of stratified waterflooding by pseudo relative permeability curves

Abstract: In fluid-injection projects, such as waterflooding, vertical permeability variation may have a significant effect on sweep efficiency. A method has been developed for calculating pseudo relative permeability curves which reflect the reservoir stratification. These curves can be used in 2-dimensional areal reservoir simulators to approximate the 3-dimensional solution. The pseudo relative permeability curves are based on a mathematical model for calculating the vertical displacement efficiency using a stratified reservoir concept. Equations for calculating the pseudo relative permeability curves, are presented, and theoretical concepts leading to their development from the stratified model are discussed. A field case example illustrates use of the curves in reservoir simulation. It is pointed out that use of relative permeability curves which do not describe vertical effects in the reservoir can lead to incorrect results when used in 2-dimensional areal models.

Isobaric measurement of gas permeability of polymers

Abstract: The principles and design of a gas permeability measuring instrument based on thermal conductivity measurement are described. Since the thermal conductivity of a gas mixture is dependent upon the partial pressure fraction rather than absolute partial pressure of sample gas, and the permeation rate of reference and sample gases through polymer films differe considerably, a pressure-equalizing device is necessary for the accurate measurement of gas permeability. The three types of measurements—integral, differential (flow method), and decay rate measurements—can be used with the instrument. The results of permeability constants and diffusion constants obtained with the methods showed good agreement with the conventional vacuum-type method. With proper selection of methods, the instrument can measure the gas flux through the range of 10−10 to 10−3 cm3 (STP)/cm2 sec cm Hg. Some advantages of the methods are discussed.

Determination of in-situ hydraulic parameters in jointed rock

Abstract: A ROCK MASS IS ANISOTROPICALLY DISCONTINUOUS BECAUSE OF FRACTURING. THE GROUNDWATER FLOW THROUGH SUCH A MEDIUM IS DETERMINED BY THE JOINT DISTRIBUTION AND GEOMETRY; THE PERMEABILITY OF INTACT ROCK IS GENERALLY NEGLIGIBLE COMPARED WITH THE HYDRAULIC CONDUCTIVITY OF JOINTS. IT IS ASSUMED THAT THE ROCK IS DIVIDED BY SEVERAL SETS OF PARALLEL JOINTS. THE PROBLEM OF DETERMINING THE ROCK MASS HYDRAULIC PARAMETERS WILL BE APPROACHED THEORETICALLY. FIELD TESTING REQUIREMENTS INCLUDE EITHER A PUMPING TEST OR A DILUTION TESTS. PRACTICAL SUGGESTIONS REGARDING THE PERFORMANCE, OF THESE TESTS IN THE FIELD WILL BE GIVEN. /AUTHOR/

An Investigation Into The Changes Of Permeability Occurring In A Sandstone When Failed Under Triaxial Stress Conditions

Abstract: Experimental results obtained during the initial investigations of a study intended to examine the permeability of samples of coal measure strata under various triaxial stress conditions are described. Many investigators have studied the effect of stress on the permeability of rock, usually in the field of oil reservoir engineering. Two general lines of approach are evident. One used is to subject a rock sample to hydrostatic pressure. Gas or water then is passed through a sealed core mounted inside a high pressure hydraulic bomb. The second approach is to employ a so-called triaxial state of stress. Here radial confining pressure and axial stress are applied independently. The permeability is measured in the direction of the axial load. This new technique for studying the fracture of rocks is discussed. Using simple methods, much can be learned about the behavior of rocks under triaxial stress. That rocks start to fracture long before ultimate failure, a fact often postulated by other workers, is clearly demonstrated. Consistent quantitative results have been obtained for the onset of fracture. (12 refs.)

Permeability determination for predicting rates of consolidation

Abstract: A THEORETICAL AND EXPERIMENTAL EVALUATION OF IN-SITU CONSOLIDATION TESTS SUGGESTS THAT ONLY THE COEFFICIENT OF PERMEABILITY MAY BE DETERMINED WITH ANY RELIABILITY. THE EFFECTS OF THE SHAPE OF A CYLINDRICAL PIEZOMETER IN A CROSS- ANISOTROPIC SOIL ARE DISCUSSED, AND SOLUTIONS TO FACILITATE THE INTERPRETATION OF THE CONSTANT HEAD IN IN-SITU PERMEABILITY TESTS ARE PRESENTED. FIVE PUSH-TYPE CYLINDRICAL PIEZOMETERS OF DIFFERENT LENGTH AND THE SAME DIAMETER WERE USED TO DETERMINE THE ORDER OF MAGNITUDE OF THE APPARENT DIRECTIONAL PERMEABILITIES OF SEVERAL SOIL DEPOSITS. OEDOMETER CONSOLIDATION TESTS WERE PERFORMED ON SPECIMENS TAKEN VERTICALLY AND HORIZONTALLY FROM EACH SOIL DEPOSIT, AND THE COEFFICIENT OF PERMEABILITY WAS CALCULATED FROM TERZAGHI'S CONSOLIDATION THEORY. AT THE END OF EACH LOAD INCREMENT, FALLING-HEAD PERMEABILITY TESTS WERE CONDUCTED TO OBTAIN THE COEFFICIENT OF PERMEABILITY DIRECTLY AND TO CHECK ON THE VALIDITY OF DARCY'S LAE. THE THREE DIFFERENTLY DETERMINED VERTICAL COEFFICIENTS OF PERMEABILITY WERE COMBINED WITH THE LABORATORY-DETERMINED MODULUS OF VOLUME CHANGE TO CALCULATE THE FIELD RATES OF CONSOLIDATION. THESE RATES OF CONSOLIDATION WERE COMPARED WITH FIELD PERFORMANCE RECORDS. DETAILS OF TWO OF FIVE CASE RECORDS ARE PRESENTED, AND CONCLUSIONS ARE DRAWN REGARDING THE BEST METHODS OF PREDICTING FIELD CONSOLIDATION RATES. /RRL(A)/

Radial flow cell

Abstract: A radial flow cell and associated method for measuring the directional permeability of a porous rock sample. While the sample is constrained in the flow cell, fluid under pressure is forced radially through it. Directional permeability is determined by comparing the relative amounts of fluid flowing out of the sample into distinct collecting areas.

Polymer solution flow in porous media

Abstract: Waterflood prediction techniques which consider areal sweep and reservoir stratifiation have been used to evaluate the effect of improved mobility ratio on oil recovery If accurate relative permeability data are available and if stratigraphic variations in the reservoir are known, then these prediction techniques may lead to a rough approximation of the performance of a polymer flood However, such prediction techniques fail to consider that the apparent flow resistance to a polymer solution depends on flow velocity, as well as permeability These rate- dependent effects may be significant in a pattern flood, since fluid velocity is not constant They may also be significant in a heterogeneous reservoir Under favorable conditions, some rate-dependent fluids will tend to even out the flood front in a stratified reservoir and thereby increase oil recovery This effect cannot be anticipated with conventional waterflood prediction techniques A method is described for the analysis of rate-dependent effects in the flow of polymer solutions through unconsolidated porous media Experimental data are presented for solutions of polyacrylamide, polyethylene oxide, and polysaccharide The results of the data are illustrated by graphical representations

Unsteady-state gas permeability of wood.

Abstract: Steady-state permeability experiments yield a single value for permeability in each of the three structural directions of wood. A high value indicates that passage through the wood is easy, but it does not necessarily mean that all voids are filled readily with a fluid.

Soil hydraulic properties determined with water and with a hydrocarbon liquid.

Abstract: Hydraulic properties of three soils were com- tained with oil to those of water was not pos- pared using either water or a hydrocarbon oil sible. The relative permeability for both_flrlids as the wetting fluid. Equations r'elating various showed better agreement because bubbling properties for oil were also valid for water pressures were similar. However, the pore-size when appropriate values for water were used. distribution index for water was sonewhat As difierences in saturated permeabilitv were lower than that for oil. not consistent, a direct transfer of dita ob- INTRODUCTION Several authors (7, 2, 5, 7 ) have reported on hydraulic properties of porous media where a hydrocarbon oil was used as a wetting fluid (this oil is a core test fluid, formerly called Soltrol, obtained from the Phillips Petroleum Company, Bartlesville, Oklahoma). Brooks and Corey (2) developed a theory on functional relation- ships using these properties and verified their existence experimentally. They also described requirements for similitude expressed in terms of the hydraulic properties of porous media. Laliberte et al. (5) proposed a relationship that can be used to estimate permeability as a function of either capillary pressure or saturation. They used oils in a disturbed as well as in an undisturbed state. Van Schaik and Laliberte (7) studied the effect of saturation techniques on various hydraulic properties. A further step toward solution of flow problems in the field is the application of the above findings to soil-water systems. It is expected that the soil structure will be less stable with water than with oil (5) and, in most cases, a different pore-size distribution will probably be found for each fluid. In addition to this problem, the wetting and interfacial problems in the presence of contaminants are of importance (6). To my knowledge, the only study in which the method of Brooks and Corey has been applied to soil-water systems is that of Brust et al. (3), who calculated permeability values from desaturation data and reported fair agree- ment between these values and those found by measuring conductivity in the fleld. Howevet, the bubbling pressures they found were lower than those expected for clay loam soils. The purpose of this study was to determine how the various hydraulic properties of soils as found with oil can be applied to soil-water systems.

The effect of the test fluid and test method in the measurement of the permeability of porous metal bearings

Abstract: Previous work on the determination of the fluid permeability of porous materials is reviewed, and methods for the measurement of the gas and liquid permeability coefficients of porous metal bearings are described. It is shown that the liquid permeability in porous metal is not independent of time and pressure as is the gas permeability. By the use of relatively simple experimental methods, the influence of surface-active additives in the mineral oil on the liquid permeability can be studied. By a complete understanding of the interactions between the lubricating oil and the metal surfaces of the porosity, an improvement in the performance prediction of porous metal bearings is to be expected.

Water permeability of disperse systems

Abstract: The interrelation between structure-sorption characteristics and the water permeability of ion-substituted forms of clay minerals is investigated.

Permeability-strength relationships in porous materials

Abstract: Design of systems utilizing porous materials, e.g., transpiration-cooled systems, may place requirements on both, mechanical and flow-control (permeability) properties. Equations relating porosity and strength are developed assuming a simple cubic porous structure. The theoretical expressions are then compared with experimental data on porous beryllium and stainless steel materials, and good agreement is shown. Implicit relations are then developed which relate permeability to strength and density, and which include a materialdependent constant that is determined experimentally. Empirical fits to these relations are then manipulated to show some practical design consequences. It is seen that for a given material with required permeability for design, there is an optimum particle size which will yield maximum strength. The maximum strength, which varies with permeability to the minus i power, is determined for the beryllium and stainless steel example materials. It is also seen that the relative density, for maximum strength, is 0.81 (porosity of 0.19) which is independent of the material and the permeability.

Effects of Porosity and Permeability on In-situ Combustion Fuel Consumption

Abstract: A method is presented for estimating field fuel consumptions by adjusting laboratory in situ combustion fuel consumption data for the effects of formation porosity and permeability. Results from combustion experiments were used to establish the reaction kinetic and heat loss parameters in an in situ combustion model. After attaining satisfactory agreement between calculated and experimental results, both for unconsolidated and consolidated media, the model was used to calculate the effects of changes in porosity and permeability on the fuel consumption. Calculations were made for a wide range of crude-oil viscosities. The study showed that porosity and permeability have marked effects on fuel consumption, and that these effects depend on the crude-oil viscosity. (15 refs.)

Low-Permeability Gas Well Performance At Constant Pressure

Abstract: The long-term production performance of low-permeability gas wells producing at constant pressure from a large gas reserve is analyzed in detail. Extremely long shut-in periods are required in such wells to obtain reasonably accurate fully built-up pressures for use in material-balance calculations of reserves. It is shown, however, that following the long transient flow periods for these wells, definite production decline characteristics become evident which provide a very reliable reserve determination method. This production decline performance is analyzed in detail, and techniques are presented for analyzing pressure build-up data to obtain the gas permeability of the formation and the effectiveness of the fracture treatment. From these data, it is shown that the abandonment pressure (and thus the recovery efficiency) can be accurately calculated.