Abstract: Techniques for determining reservoir formation properties include generating digital models of core samples taken from one or more reservoir formations based on corresponding images of the core samples; determining a pore throat size distribution of the core samples based on the generated digital models; determining corresponding capillary pressure curves and corresponding NMR value distributions of the core samples with one or more numerical simulations; generating one or more machine-learning (ML) models based on the pore throat size distribution, corresponding capillary pressure curves, and corresponding NMR value distributions of the core samples; adjusting the one or more ML models with one or more reservoir data of the one or more reservoir formations; generating adjusted capillary pressure curves and NMR value distributions from the one or more adjusted ML models; and determining a reservoir formation specific pore throat size distribution from at least one of the adjusted capillary pressure curves or

Abstract: Provided are a method and a system for transient electromagnetic-induced polarization field separation and multi-parameter information extraction. The method includes the following steps: obtaining electromagnetic data influenced by an induced polarization effect; performing a separating treatment of an induced polarization field and an electromagnetic field on the electromagnetic data influenced by the induced polarization effect to obtain a pure electromagnetic response field and a pure induced polarization response field; based on the pure electromagnetic response field and the pure induced polarization response field, respectively performing a multi-parameter information inversion to complete an extraction of geoelectric parameters. This system includes a data obtaining module, a field separation module and a parameter inversion module.

Abstract: A distributed three-dimensional (3D) induced polarization (IP) data acquisition and processing device, including: a transmitter module, a computer and multiple receiver modules, where the transmitter module is configured to transmit a preset current signal to a ground where a region to be measured is located, and record the current signal in real time; the receiver modules each are configured to acquire a voltage signal and an apparent polarizability of the ground where the region to be measured is located, and record the voltage signal and the apparent polarizability in real time; and the computer is configured to acquire the current signal, the voltage signal and the apparent polarizability, respectively process the current signal and the voltage signal to obtain an apparent resistivity of the region to be measured, and analyze, according to the apparent polarizability and the apparent resistivity, a polarizability and a conductivity of the region to be measured.

Abstract: A method of determining pore size of a porous material. The method includes saturating the porous material with a conducting liquid. Measuring, with an electro-acoustic device, a phase of the seismo-electric or electro-seismic signal at a single frequency or multiple frequencies. Calculating an average pore size from the measured phase of the seismo-electric or electro-seismic signal at single frequency using a theory that takes into account the hydrodynamic relaxation of the conducting liquid inside of the pores of the porous material. Calculating pore size distribution from the similar measurement conducted at multiple frequencies using the same theory.

Abstract: A system for mapping and characterizing a hydrocarbon plume in seawater by measuring seawater capacitance. Multiple streamer cables are towed in the sea behind a ship, each at a different depth, simultaneously. Each streamer cable includes transmitters and receivers at the free end thereof. The free ends of the streamer cables pass through the plume and the transmitters transmit an electrical current into the plume. The receivers detect any secondary signals produced by capacitive effects of the hydrocarbon or hydrocarbon and dispersant surrounded by conductive seawater in response to the inducing electrical current. Pre-amplifiers connected to the receivers and a two-step calibration procedure and various grounding and shielding steps provide noise rejection. An electronics system on board the ship processes the secondary signals to provide immediate development of detailed maps of plume location, and to provide tracking and characterization of how the plume changes shape and character over time.

Abstract: A method used in electrical investigation of geological formations surrounding a borehole comprising: determining S1 a grid of iso-parameter lines GR in a two-dimensional plane, the parameter being an electrical parameter characterizing the geological formation, injecting in a localized manner a survey current IS into a selected zone SZ of the geological formations GF surrounding the borehole BH, and measuring S2 a measured value of a quantity characterizing the electrical parameter of the selected zone based on the survey current, and interpolating S3 an interpolated electrical parameter value of the selected zone SZ based on the measured value and the grid of iso-parameter lines GR.

Abstract: The invention relates to the field of electrical exploration and to the methods of determination of subterranean formations properties by means of electric parameters of subterranean formations measuring and separating of the parameters measured. The invention can be applied both in surface and marine electrical exploration using controlled sources of electromagnetic field, and is used in gas and oil exploration for searching and delimitation of oil and gas reservoirs basing on segregation of response from stratum, secondarily changed due to hydrocarbons migration, to split the measured signal to available components. The invention provides for a set of techniques that enable a layer-by-layer determination of geoelectrical parameters values, as well as process characteristics of induced medium polarization and electromagnetic induction.

Abstract: A device for detecting polarization direction of a ferroelectric is provided. From a measurement signal provided through a probe disposed in contact with or near the surface of a ferroelectric, a demodulation means generates a detection signal having a signal level corresponding to a capacitance change of the ferroelectric due to application of an alternating electric field to a capacitor component formed in the ferroelectric directly below the probe. A synchronous detection means performs synchronous detection of the detection signal based on a synchronous signal and generates a polarization direction detection signal corresponding to the polarization direction of the ferroelectric. A pseudo-noise signal generation means generates a pseudo-noise signal with the same frequency as that of the electric field signal and a different phase and amplitude therefrom.

Abstract: A method for survey of hydrocarbon deposits in a researched profile of sea-bottom comprises providing a generator generating pulse electric current with a generator frequency in a towable generator line exciting electric field signals measured by sea-bottom stations synchronized with the generator, forming space-domain data arrays for the generator frequency and for higher odd harmonics frequencies nearest thereto, forming time-domain data arrays for selected offsets, inversion of the time-domain and space-domain data, and determining a bottom strata resistivity and polarization characteristics for the researched profile, based the inversion's results. The inversion preferably encompasses synchronizing and adjusting the generator line and electric field signals, dividing them into a frequency branch, including a fast Fourier transform and a robust summation producing the space-domain arrays, and a time-domain branch, including a robust summation producing the time-domain arrays.

Abstract: Method for removing air wave noise from shallow water controlled source electromagnetic survey data, using only the measured data and conductivity values for sea water (140) and air. The method is a calculation performed numerically on CSEM data and resulting in an estimate of those data that would have been acquired had the water layer extended infinitely upward from the seafloor. No properties of the sub-sea sediments are used. Synthetic electromagnetic field data are generated for (a) an all water model (141) and (b) an air-water model (146-147) of the survey region. These simulated results are then used to calculate (148-150) electromagnetic field values corresponding to a water-sediment model with water replacing the air half space, which represent measured data adjusted to remove air wave noise.

Abstract: The invention relates to the field of electrical exploration and to the methods of determination of subterranean formations properties by means of electric parameters of subterranean formations measuring and separating of the parameters measured. The invention can be applied both in surface and marine electrical exploration using controlled sources of electromagnetic field, and is used in gas and oil exploration for searching and delimitation of oil and gas reservoirs basing on segregation of response from stratum, secondarily changed due to hydrocarbons migration, to split the measured signal to available components. The invention provides for a set of techniques that enable a layer-by-layer determination of geoelectrical parameters values, as well as process characteristics of induced medium polarization and electromagnetic induction.

Abstract: Methods and apparatuses for measuring an electrical property of the ground. The apparatus includes a graphite electrode. The graphite electrode includes a graphite body and a first and second opening. The first opening extends longitudinally throughout the graphite body and is configured to receive a multi-wire cable. The second opening is configured to secure one or more wires of the multi-wire cable to the graphite body. Using a graphite electrode, measurements of the ground can be made over a long period of time without having to clean or otherwise maintain the electrodes because the graphite material withstands operating conditions over many years without degradation.

Abstract: Methods and apparatuses for measuring an electrical property of the ground. The apparatus includes a graphite electrode. The graphite electrode includes a graphite body and a first and second opening. The first opening extends longitudinally throughout the graphite body and is configured to receive a multi-wire cable. The second opening is configured to secure one or more wires of the multi-wire cable to the graphite body. Using a graphite electrode, measurements of the ground can be made over a long period of time without having to clean or otherwise maintain the electrodes because the graphite material withstands operating conditions over many years without degradation.

Abstract: An apparatus for measuring induced polarization of the ground. The apparatus includes a polarizable contact member configured to transmit a current to the ground. An electrode includes a first conductor and a second conductor. The first conductor is coupled to the polarizable contact member. A non-polarizable contact member is coupled to the second conductor of the electrode and is configured to measure an electrical potential associated with the current.

Abstract: Capillary pressure curves can be derived from nuclear magnetic resonance (NMR) pore size distributions. These derived capillary pressure curves can be used to derive the displacement pressure, the fractional bulk volume of mercury at infinite pressure and a geometrical factor. These factors can be used to accurately predict permeability from an NMR derived capillary pressure curve.

Abstract: Multiple arrays of electric or magnetic transmitters and receivers are used in a borehole geophysical procedure to obtain a multiplicity of redundant data suitable for processing into a resistivity or induced polarization model of a subsurface region of the earth.

Abstract: An improved method and apparatus for detecting telluric noise information while performing induced polarization prospecting. Telluric noise electrodes are positioned on an equipotential line lying about an input current electrode forming part of a conventional IP electrode spread. The telluric noise record obtained from the noise electrodes is essentially free of IP input signal waveform.

Abstract: Logging means and methods are disclosed for distinguishing between dispersed and laminated clay in earth formations. A wireline apparatus is employed consisting of a multifrequency induced polarization logging tool operating at extremely low frequencies, combined with other logging tools which measure the total amount of clay in the formation. A determination is then made of the fraction of the total clay content in the formation which is due to laminated clay.

Abstract: An in-situ method of determining the pore size distribution, capillary pressure curve, and permeability of a formation using induced polarization logging measurements. The induced polarization (IP) voltage decay curve is measured opposite the formation of interest and the voltage decay curve is decomposed into a series of relaxation times related to the pore size distribution. The capillary pressure curve and the permeability are approximated from the pore size distribution. The measurements can also be made in the frequency domain using various frequencies to obtain the variation in phase shift with frequency. The variation in phase shift with frequency can be correlated with previous core measurements to obtain the pore size distribution, capillary pressure curve and formation permeability.

Abstract: The stimulus signal for an induced polarization logging system is presented to the formation intermittently, alternately being applied and removed as a square wave of alternating polarity, and the response signal amplification level is time gated with the stimulus signal.

Abstract: An in-situ method of determining the pore size distribution, capillary pressure curve, and permeability of a formation using induced polarization logging measurements. The induced polarization (IP) voltage decay curve is measured opposite the formation of interest and the voltage decay curve is decomposed into a series of relaxation times related to the pore size distribution. The capillary pressure curve and the permeability are approximated from the pore size distribution. The measurements can also be made in the frequency domain using various frequencies to obtain the variation in phase shift with frequency. The variation in phase shift with frequency can be correlated with previous core measurements to obtain the pore size distribution, capillary pressure curve and formation permeability.

Abstract: An apparatus includes a logging tool having electrodes for introducing a current into a downhole formation and for detecting a voltage produced in the formation by the current. The current is provided by a transmitter circuit, and the voltage is received and processed by a receiver circuit including a computer programmed to provide induced polarization and resistivity measurements based on the detected voltage. The electrodes are equidistantly spaced but are adjustable (either on a single logging tool or as between different logging tools) so that various logging runs can be made to obtain different measurements whereby the intrinsic complex resistivity (induced polarization) of formation layers can be suitably resolved. The apparatus also includes a contact resistance measurement circuit for making measurements used by another computer means to determine the contact resistance of each of the electrodes.

Abstract: An improved input circuit for an electronic vehicle speed control unit is disclosed. An ignition current sensor coil is adapted to have a voltage differential signal induced therein each time an ignition pulse is generated by the vehicle engine. Electrical noise signals generated by the vehicle engine appear as common mode signals across the ignition current sensor coil. The ignition current sensor coil is connected at each end to a capacitor, both of which are connected to ground potential. The ends of the ignition current sensor coil are further connected to the inputs of a differential amplifier. The capacitors appear in a series loop with the ignition current sensor coil for the differential voltage signals and, consequently, provide tuning for inductance. However, the capacitors appear in parallel with one another to ground potential with respect to the common mode noise signals, thereby providing high frequency noise rejection for the input circuit.

Abstract: A method of logging a subsurface formation surrounding a borehole includes the recording of an induced polarization log, the recording of a nuclear log of delayed gamma-rays from the activation of aluminum in the formation, and the recording of a nuclear log of natural gamma-rays from potassium in the formation. The induced polarization log and the nuclear logs are combined to identify the composition of the lithology of the subsurface formation.

Abstract: An apparatus is disclosed for borehole measurements of the induced polarization of earth formations. The apparatus consists of an induced polarization logger capable of measuring both in-phase and quadrature conductivities in the frequency domain. A method is described which uses these measurements to determine cation exchange capacity per unit pore volume, Q.sub.v, brine conductivity, C.sub.w, and oil and water saturations, S.sub.o and S.sub.w, in shaly sands.

Abstract: Apparatus and method for generating a record of telluric noise which is substantially free of induced polarization signals and is suitable for removal of noise components from induced polarization signal records. The apparatus includes a single pair of telluric noise sensing electrodes positioned in alignment with, but substantially beyond the ends of, a somewhat conventional induced polarization electrode spread. The method includes recording of telluric noise occurring at the time of detection of induced polarization signals and the subtraction of a fraction of the telluric noise record from the induced polarization signal records.