Abstract: Techniques for modeling subterranean characteristics by combining physical and numerical simulations using limited amounts of subsurface full diameter core samples via orthogonal experimentation schemes. Systems and methods applying synchronous fitting and prediction of physical simulation and numerical simulation to obtain the equivalent permeability of fracture cells in numerical simulation, to provide a basis for assigning a value to the equivalent fracture cell permeability during numerical simulation. According to the specific subterranean reservoir characteristics, the water invasion orthogonal experiments are completed by combining physical simulation with numerical simulation to analyze the main factors of water invasion in reservoirs.

Abstract: The disclosure presents an apparatus and system to allow for multiple downhole sensors to be oriented at varying azimuthal angles to collect reservoir data across varying azimuthal directional arcs. In one aspect, two sensors can be attached to a downhole tool system, one being oriented azimuthally 90° different than the other sensor. In other aspects, a method and system are presented to utilize the collected reservoir data to compute a porosity anisotropy and permeability parameters. These parameters can be utilized to further derive reservoir characteristic parameters, such as a permeability ellipsoid that can identify the primary axis of drainage of the reservoir and the minimum axis of drainage of the reservoir. The derived reservoir characteristic parameters can be utilized to modify a well system operation plan, such as to improve the well system production over a time period.

Abstract: The present disclosure discloses a resistivity measurement method, device and system. The method comprises: placing a core to be measured into the core holder after a 100% saturated water treatment, and injecting a predetermined confining pressure by the confining pressure pump; turning on the displacement source to carry out a displacement, and at an interval of a predetermined time period, acquiring a current value by the ammeter and a voltage value by the voltmeter; determining a resistivity of the core according to the current value, the voltage value, an arc length of the curved electrode, and a radius and a length of the core. The present disclosure can realize a rock resistivity measurement in a vertical direction under formation conditions for a plunger-type core, without needing to change the core preparation technology or method.

Abstract: A pressure cell system includes a pressure cell configured to house a sample within inner walls of the pressure cell. An injectable medium is injected by an injection system of the pressure cell system into the pressure cell in a gap between the sample and the inner walls. The injectable medium in the pressure cell is heated by a heating element of the pressure cell system. A pressure inside the pressure cell is measured by a pressure gauge of the pressure cell system. A temperature in the pressure cell is measured by a temperature gauge of the pressure cell system. Microwave permittivity measurements of the sample are captured by a coaxial resonator system of the pressure cell system. The microwave permittivity measurements of the sample are captured at different combinations of temperatures and pressures. The microwave permittivity measurements include measurements of permittivity of gas under pressure at plural frequencies.

Abstract: An electromagnetic measurement tool for making multi-frequency, full tensor, complex, electromagnetic measurements includes a triaxial transmitter and a triaxial receiver deployed on a tubular member. An electronic module is configured to obtain electromagnetic measurements at four or more distinct frequencies. The measurement tool may be used for various applications including obtaining a resistivity of sand layers in an alternating shale-sand formation; computing a dielectric permittivity, a conductivity anisotropy, and/or a permittivity anisotropy of a formation sample; and/or identifying formation mineralization including discriminating between pyrite and graphite inclusions and/or computing weight percent graphite and/or pyrite in the formation sample.

Abstract: A core sample holder assembly for performing core flood experiments includes a first end cap having a first cylindrical body with a first central chamber and a first inner end that is ring shaped, and a second end cap having a second cylindrical body with a second central chamber and a second inner end that is ring shaped. Three flow lines are spaced elevationally apart, the three flow lines extending from a first outward end to a first inward facing surface of each end cap. A flexible sleeve circumscribes the first end cap and the second end cap. A test sample bore is defined by the first inner end, the second inner end, and an inner diameter surface of the flexible sleeve. A central axis extends through the first end cap, the second end cap, and the flexible sleeve, the first end cap, the second end cap, and the flexible sleeve being axially aligned.

Abstract: Test apparatus for testing porous material such as used in roadway base or building foundations may be deployed in the field at various test sites. The test apparatus includes electrodes that contact the porous material under test and a sensor unit that supplies electromagnetic signals to the porous material. Response signals reveal electrical parameters such as complex impedance which can be equated to material properties such as density and moisture content. Reference may be made to empirical correlations made in laboratory tests using the same test apparatus to enable the effects of the test apparatus on the measurement to be accounted for. The electrodes may include flexible coplanar electrodes that reduce air gaps when in contact with the porous material.

Abstract: A determination of the free water level for a hydrocarbon-bearing reservoir is provided that accounts for the different classified rock types (that is, facies) in the reservoir. The free water level for each unique combination of facies is determined using a least squares minimization between a reference bulk volume of oil (Bvolog) determined from well logs a bulk volume of oil (Bvocalc) calculated from a saturation height function for each of the facies present in the reservoir. Systems and process for determining the free water level are provided.

Abstract: A multi-functional multi-field coupling seepage experiment device includes a device body, a stress field control system, a temperature field control system, a fluid loading control system and a fluid seepage measurement system. The present invention further discloses seepage experiments performed on tight gas, shale gas, tight oil, shale oil, natural gas hydrate and geothermal heat in a multi-field coupling state of a temperature field, a stress field, a pore pressure field and a seepage field.

Abstract: Irreducible water saturation of fluid-storing porous reservoir rock is determined using methods that include obtaining a reservoir rock sample from the underground fluid reservoir; performing mercury saturation measurements on the reservoir rock sample for different mercury injection pressure values to obtain mercury saturation values for the different mercury injection pressure values; and estimating the irreducible water saturation (Swirr) from the mercury saturation values and the mercury injection pressure values by correcting for surface films of fluid retained on pore walls of the reservoir rock.

Abstract: Methods are provided for measuring the permeability and/or porosity of a rock sample having an “ultra-low” permeability while accounting for adsorption. The rock sample may be a sample obtained from a geological formation. The methods account for adsoption of gas within the rock samples.

Abstract: An attenuation device for variably attenuating an electromagnetic signal radiated by a microwave source includes a cylinder formed by a cylinder wall having a first flange and a second flange. The cylinder wall is closed at a first end thereof by the first flange and at a second end thereof by the second flange. The cylinder wall is pierced at the first end by a liquid inlet/outlet port and at the second end by an air inlet/outlet port. The attenuation device further includes a piston being arranged in the cylinder and being displaceable in the cylinder. The piston bounds with the first flange a variable volume filled with an electromagnetic energy absorbing liquid. The attenuation device further includes a displacement sensor for sensing a position of the piston the cylinder.

Abstract: A disclosed fracture characterization method includes: collecting three-dimensional resistivity measurements of a volume surrounding an open borehole; analyzing the measurements to determine parameters describing fractures in the volume; and providing a report to a user based at least in part on said parameters. A fluid with a contrasting resistivity is employed to make the fractures detectable by a directional electromagnetic logging tool in the borehole. Illustrative parameters include fracture direction, height, extent, length, and thickness. The resistivity measurements can be augmented using a borehole wall image logging tool. Also disclosed are fracturing methods that include: positioning a directional electromagnetic logging tool proximate to a formation; fracturing the formation; monitoring fracture progression with said tool; and halting the fracturing when measurements by said tool indicate that a predetermined set of criteria have been satisfied.

Abstract: A method includes applying a current to a specimen to deposit a material on the specimen. The method also includes determining a quantity of the material deposited at multiple locations of the specimen and determining anisotropic conductive characteristics of the specimen based on the quantity of the material deposited at the multiple locations on the specimen.

Abstract: An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

Abstract: An open ended coaxial probe is disclosed that can be used to measure the dielectric properties of solids. According to some embodiments, the probe is specially designed to make good contact with solids having flat or non-flat surfaces. This design relies on forcing a good contact between the solid surface with both the center conductor and outer conductor of the coaxial probe. A method is also described in which the coaxial probe is used to monitor the dielectric permittivity of cylindrical samples such as rock cores drilled from a well. Also described are methods of using the coaxial probe to provide a continuous log of the dielectric permittivity of a rock core.

Abstract: A formation core analysis system can include an inner barrel and a toroidal electromagnetic antenna which transmits electromagnetic signals into a formation core when the core is received in the inner barrel. Another formation core analysis system can include an inner barrel and multiple longitudinally spaced apart electrodes which electrically contact a formation core when the core is received in the inner barrel. A speed of displacement of the core into the inner barrel may be indicated by differences between measurements taken via the electrodes as the core displaces into the inner barrel. A method of measuring resistivity of a formation core as the core is being cut can include transmitting electromagnetic signals into the core from a toroidal electromagnetic antenna as the core is being cut by a coring bit.

Abstract: According to various embodiments, a method may include measuring a first capacitance of a sample at a first frequency using a measurement system, measuring a second capacitance of the sample at a second frequency using the measurement system, calculating a ratio of the first capacitance to the second capacitance, and determining a formation water resistivity or conductivity of the sample using the ratio.

Abstract: A method and system for determining a rock matrix dielectric permittivity. The method and system use a matching liquid with a temperature dependant permittivity. The matching liquid may be used in an automated and/or downhole system for measuring matrix dielectric permittivity of rock formations.

Abstract: An apparatus for measuring permittivity of a sample. The apparatus includes: a sample chamber including a sealed space portion in which a sample to be measured is put; a pressure adjusting unit for varying pressure by applying water pressure to the space portion of the sample chamber; a permittivity sensor for measuring permittivity of the sample and disposed outside the sample chamber; measurement conducting wires including conductors, installed to contact the sample and connected to the permittivity sensor by using electric wires; and a data logger for storing data relating to permittivity that is measured by the permittivity sensor.

Abstract: A high-voltage discharge circuit diagnostic system includes a high voltage DC link with a positive DC link and a negative DC link, a first resistor selectably connectable between the positive DC link and the negative DC link, and a second resistor connected between the positive DC link and the negative DC link. A control module connects the first resistor between the positive DC link and the negative DC link until the high voltage DC link discharges to a first voltage after which the control module disconnects the first resistor from between the positive DC link and the negative DC link to permit continued discharge of the high voltage DC link through the second resistor to a second voltage through an elapsed time period. The control module diagnoses a fault in the second resistor based upon the first voltage, the second voltage, and the elapsed time period.

Abstract: An open ended coaxial probe is disclosed that can be used to measure the dielectric properties of solids. According to some embodiments, the probe is specially designed to make good contact with solids having flat or non-flat surfaces. This design relies on forcing a good contact between the solid surface with both the center conductor and outer conductor of the coaxial probe. A method is also described in which the coaxial probe is used to monitor the dielectric permittivity of cylindrical samples such as rock cores drilled from a well. Also described are methods of using the coaxial probe to provide a continuous log of the dielectric permittivity of a rock core.

Abstract: A method for analyzing fluid withdrawn from a subsurface formation includes disposing the withdrawn fluid in a chamber and maintaining the fluid in the chamber substantially at a same temperature and pressure as exists in the subsurface formation. Electric current is passed through the fluid in the chamber using at least one electrode made from a selected metal, the electric current comprising direct current and alternating current of frequency sufficient to determine at least one of (i) resistance of the fluid sample in the chamber directly and (ii) from the direct current determine a polarization resistance of the at least one electrode.

Abstract: The present invention relates to a measuring device (10) of the electric properties of solid or liquid geological samples, such as, for example, rocks, preferably from oil or gas reservoirs, and saturation fluids of the same, comprising a hollow body (11, 12) consisting of a first upper half-shell (11) and a second lower half-shell (12), the upper and lower half-shells (11, 12) coaxially sliding one inside the other, inside the body (11, 12) there being a housing seat (23) for a substantially cylindrical sample, two pairs of electrodes (13, 14) being envisaged facing the housing seat (23) for the injection of current into a sample and for the measurement of the voltage at the ends of the sample, characterized in that the pairs of electrodes (13, 14) are pairs of coplanar electrodes, each situated at one end of the housing seat (23).

Abstract: An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

Abstract: A method and apparatus for measuring the resistivity anisotropy of cylindrical rock samples is disclosed. The measurement setup includes two pairs of electrodes that contact the sample surface. The ring electrodes of the first pair are disposed on the cylindrical surface of the sample. The cap electrodes of the second pair are mounted at the sample ends. Two differences in potentials are measured. One of the cap electrodes and the nearest ring electrode are used to measure the first difference that results from current injected through the remaining cap and ring electrodes. The second difference is measured between the two ring electrodes, while current is injected through the first and second end cap electrodes. These two differences are inverted for the anisotropy coefficient, horizontal and vertical resistivity.

Abstract: Systems and methods are described for determining dielectric permittivity for core plugs extracted from the field or cores re-saturated with various fluids. The relative dielectric constant of reservoir core plugs is measured in controlled condition of temperature, pressure and fluid saturation within a confined cell. Four-points resistivity measurements of the rock sample in the confined cell is also provided under the controlled temperature, pressure and fluid saturation conditions.

Abstract: Methods of using resistivity ahead of a drill bit measurements obtained while drilling a subterranean well using a drilling mud. Resistivity data ahead of the bit is gathered during drilling and prior to penetrating a region of interest of a known subterranean formation using the drill bit and the drilling mud. The drill string progresses at known dip and azimuth angles toward the subterranean formation. The resistivity data is used to determine pore pressure ahead of the drill bit in the formation as a function of resistivity ahead of the drill bit in the formation while the drill bit advances toward but before the bit penetrates the formation while drilling.

Abstract: A subsurface formation monitoring system and method is described. The system includes a conductive piping structure positionable within a borehole extending into a subsurface formation. The conductive piping structure is electrically decoupled from a production tubing by an insulating packer. The system also includes a downhole installed conductive casing sub that has one or more sensors. The conductive casing sub is electrically coupled to the conductive piping structure. The system further includes a surface installed power and communication module that has an alternate current generator. The power and communication module is electrically coupled to the conductive piping structure via a downhole intermediate module. The alternate current generator can inject a current signal that flows downhole to the conductive casing sub and then returns with sensor measurements to the surface power and communication module via a grounded return electrode that is coupled to the subsurface formation.

Abstract: A method and device is disclosed for evaluating simultaneously, and with the same equipment, the electric resistivity and flow parameters of a porous medium, from experimental measurements obtained from at least one multi-flow type displacement experiment which has application in oil reservoir development. The method continuously measures as a function of time the differential pressure between two ends of a sample, the electric resistivity of the sample and, for each stabilization step, at least two values of a displaced fluid production volume are also measured. A continuous curve of the displaced fluid production volume, from which flow parameters are estimated by means of a numerical flow simulator, is then deduced therefrom.

Abstract: The present invention relates to a measuring device (10) of the electric properties of solid or liquid geological samples, such as, for example, rocks, preferably from oil or gas reservoirs, and saturation fluids of the same, comprising a hollow body (11, 12) consisting of a first upper half-shell (11) and a second lower half-shell (12), the upper and lower half-shells (11, 12) coaxially sliding one inside the other, inside the body (11, 12) there being a housing seat (23) for a substantially cylindrical sample, two pairs of electrodes (13, 14) being envisaged facing the housing seat (23) for the injection of current into a sample and for the measurement of the voltage at the ends of the sample, characterized in that the pairs of electrodes (13, 14) are pairs of coplanar electrodes, each situated at one end of the housing seat (23).

Abstract: A method of measuring the compressibility, and/or the density, of small particles, and especially nano-particles, in suspension is described. The static method uses steady pressures and measures the d-c (static) compressibility of particles. The ultrasonic method utilizes an ultrasonic pulsed doppler system to measure the compressibility of particles at ultrasonic frequencies, which may differ from static values. These methods can also be used together to provide overlapping and complementary information about the particles. In addition, the ultrasonic pulsed doppler system also provides a way to measure particle density.

Abstract: A subsurface formation monitoring system comprises a conductive piping positioned within a borehole extending into the formation, a surface installed power and communication module, a downhole installed conductive casing or tubing sub comprising sensor(s) mounted on the sub, a data communication module for wireless communication of sensor measurements to the surface module, and a battery for providing power to the data communication module and the sensor. The surface module is coupled to the conductive piping and to a grounded return electrode coupled to the formation, and comprises an alternate current generator that defines an ingoing signal path along the conductive piping and sub, the ingoing signal flowing from the surface module to the sub and transmitting power from the generator to the sub. A return signal comprising sensor measurements is transmitted through a return signal path flowing from the sub to the surface module.

Abstract: An apparatus for use in a system that includes a network analyzer for determining a property, such as dielectric permittivity of a sample material as a function of frequency, the apparatus including: a cylindrical chamber for receiving the sample; a coaxial connector having a first relatively small diameter end coupleable with the analyzer and a second relatively large diameter end communicating with a side of the cylindrical chamber, the connector having inner and outer coaxial conductors; the inner conductor of the connector having a diameter that tapers outwardly from the first end to the second end, and the outer conductor of the connector having an inner surface whose diameter tapers outwardly from the first end to the second end. The chamber can accommodate relatively large samples, such as standard earth formation coring samples.

Abstract: A method of estimating a property of interest downhole according to one aspect of the disclosure may include continuously receiving a core drilled from a formation into an open end of a chamber while removing the core distal from the open end of the chamber; obtaining a measurement relating to property of interest of the core using at least one sensor; and estimating the property of interest of the core using the obtained measurement.

Abstract: A method and apparatus for determining petrophysical parameters within a geologic formation pressurizes a geologic sample through a set of predetermined effective pressures, energizes the sample at each predetermined effective pressure with an electric current and/or sonic energy, and measures a conductivity value (electrical conductivity and/or sonic velocity). Permeability and/or porosity are also measured at each pressure through a traditional method and the functions are compared so that permeability and/or porosity can be subsequently derived from a sonic or electrical measurement of a comparable sample under a effective pressure. An apparatus is also described for acquiring the measurements under tri-axial compression, with a computerized interface in one embodiment.

Abstract: The present invention relates to the use of an electronically controlled humidity chamber with temperature controls: to determine, by vapor desorption, high capillary pressures of core samples; to produce core samples with a high capillary pressure for testing electrical properties; and, using a curve of high capillary pressures from vapor desorption data, to transform a curve of high capillary pressures determined from high pressure mercury injection.

Abstract: A method and apparatus for determining petrophysical parameters within a geologic formation pressurizes a geologic sample through a set of predetermined effective pressures, energizes the sample at each predetermined effective pressure with an electric current and/or sonic energy, and measures a conductivity value (electrical conductivity and/or sonic velocity). Permeability and/or porosity are also measured at each pressure through a traditional method and the functions are compared so that permeability and/or porosity can be subsequently derived from a sonic or electrical measurement of a comparable sample under a effective pressure. An apparatus is also described for acquiring the measurements under tri-axial compression, with a computerized interface in one embodiment.

Abstract: Method and device for determining the formation factor of underground zones from drill cuttings. The device comprises a cell (1) associated with a device for measuring the electrical conductivity of the cell with the content thereof. The cell containing the drill cuttings is filled with a first electrolyte solution (A) of known conductivity (?A). After saturation of the drill cuttings by first solution (A), the global electrical conductivity (?*A) of the cell with the content thereof is determined. After discharging first solution (A), the cell containing the drill cuttings is filled with a second electrolyte solution (B) of known conductivity (?B), and the global electrical conductivity (?*B) of the cell containing the second solution and the cuttings saturated with the first solution is determined. The cuttings formation factor (FF) is deduced therefrom by combination of the measurements.

Abstract: A method and device with application to petrophysical measurements on porous rocks for measuring the resistivity anisotropy of rocks exhibiting layerings of different conductivity such as laminations is disclosed. The method comprises setting a sample saturated with a first fluid into a petrophysical measurement device allowing the sample to be subjected to drainage operations by injection under pressure of a second fluid. At least one pressure injection is established for the second fluid, and continuous and precise measurements of the variations in the complex electrical impedance of the sample at several frequencies are performed during a displacement of the saturating fluid.

Abstract: A highly accurate, fully compensated, high spatial resolution, wave propagation system for measuring dielectric constant and resistivity of fluids or solids in a cylindrical enclosure and method for measuring well core characteristics in-situ or in a laboratory. One embodiment of the invention relies on waves propagated from transmitters above and below two spaced receivers which transmit and receive electromagnetic waves via slots on the inner periphery of a cylinder structure. The data is then processed with a CPU either down hole for later retrieval or on the surface for real-time monitoring.

Abstract: The invention includes an apparatus for determining geo-electric data and the density of a porous material. A resistivity-measuring device applies an electrical current through an electrode array to that is part of a non-electrical conductive test cell that is used to measure the resistivity of the porous material that is the test cell. The test cell is a made of a rigid non-electrically conductive material and is a standard shape and dimension. The material that is the test specimen is compacted into the test cell using a standard technique so that the physical properties of the test specimen my calculated. In addition to making a set of standard physical measurement (material unit density and unit moisture content) the test cell is used to measure electrical properties of the test specimen so that a set of electrical constants can be determined for the material under test.

Abstract: Method and device for measuring the resistivity index curve (Ir) of a solid sample such as a geologic sample independently of the capillary pressure curve (Pc). Multi-frequency complex impedance measurements are carried out for a sample subjected to a radial confining pressure, during operations of drainage or imbibition of a first, initially saturating fluid, through a semipermeable membrane permeable to this first fluid, placed at a first end of a containment cell, by injection of a second fluid under pressure at the opposite end thereof. One or more injection pressure stages are applied and the continuous variations of the resistivity index (Ir) as a function of the average saturation (Sw) variation are measured without waiting for the capillary equilibria to be reached. Electrodes pressed against the sample on the periphery thereof are used, these electrodes having a given longitudinal extension in relation to the length of the sample and being connected to an impedance meter.

Abstract: An effective laboratory method for developing complete capillary pressure curves involves directly measuring an oil/water saturation profile within a cylindrical porous rock core plug. The saturation profile, which includes a free water level, is established under a known pressure gradient induced by centrifuging and is measured using image mapping techniques. The free-water level is established at a desired position within the length of the core plug and provides a reference position of zero capillary pressure to facilitate measurement of both positive and negative capillary pressures.

Abstract: A method for determining a relative clay content of at least a portion of a well core taken from a subterranean geologic formation by: determining the relationship of the clay content of the well core portion to the dielectric constant of the well core portion at a selected frequency at relatively few locations over a substantial length of the well core portion by measuring the clay content by a clay determination test such as x-ray diffraction, thin section analysis, sieve analysis or laser particle analysis and the dielectric constant at the locations; and, measuring the dielectric constant of the well core portion at a large plurality of spaced apart other locations on the well core portion at the selected frequency; translating the large plurality of dielectric measurements according to the relationship into relative clay content measurements. The dielectric constant is representative of the water constant of the well core portion, which is related to the clay content of the well core portion.

Abstract: The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

Abstract: A method of determining a parameter selected from the electrical conductivity and the volume fraction of a component in a composition comprising a plurality of components is provided. The method comprises measuring the electrical conductivity of the composition, and selecting a relationship between the conductivity of the composition and a plurality of composition parameters including, for each component, physical parameters representing the conductivity and the volume fraction of the component, said relationship being such that the components are substantially equally represented in said relationship by means of said physical parameters. The selected parameter of the component in the composition is determined by applying said relationship to the measured conductivity of the composition.

Abstract: An automated gas permeameter measures permeabilities of porous samples, such as rocks, ranging from 0.1 milliDarcys to 10 Darcys within 0.5% under dry and humid conditions. The automated gas permeameter includes a program for estimating a coarse permeablity value. The program uses the coarse value to determine settling time for pressure to reach steady state within 0.1% and optimal operating conditions, such as the setting of mass flow rates imposed on the sample. Operating conditions of the permeameter are set by the program according to the resolution and range of flow controllers, accuracy of a pressure transducer, and the limit of applicability of Darcy's law for a sample.

Abstract: The device includes a cell for a sample, delimited lengthwise by two end pieces (7, 8) and laterally by a deformable sheath (17). The end pieces are traversed by channels (14) which place their grooved inside faces in communication respectively with two sources (14, 15) at an adjustable pressure delivering respectively a first and a second fluid. Between the inside faces of the end pieces and the sample, two semipermeable membranes (12, 13) are disposed, which are permeable respectively to the first and to the second fluid. Electrodes (18, 19) are placed inside sheath (17) in contact with the sample and connected to a system (24) for measuring the electrical conductivity of the sample. The cell is placed in a body (1) associated with pressure means (28) for applying a confinement pressure to sheath (17) and membranes (12, 13). The device is designed to operate at relatively high temperatures.

Abstract: Process and apparatus for determination of permeability of porous media and thickness of layered porous media by measurement at finite frequency of streaming potential and electro-osmotic induced voltage due to applied finite frequency pressure oscillations and alternating current, respectively. The distance between application and measurement of the alternating signals at a finite frequency is small compared to the wave length. A plurality of spaced measurement electrodes provides measurement of the penetration depth of applied pressure oscillations for determination of thickness of porous layers and to largely remove the effect due to mudcake on a borehole in streaming potential measurements.