Abstract: Methods and systems for determining petrophysical parameters of a formation are provided. In one embodiment, a method includes acquiring formation data with a borehole imaging tool deployed in a well penetrating a formation and acquiring additional formation data with a dielectric logging tool deployed in the well. The method also includes calibrating the formation data acquired with the borehole imaging tool based on the additional formation data acquired with the dielectric logging tool. The calibrated formation data can then be used in determining a petrophysical parameter of the formation. Additional methods, systems, and devices are also disclosed.

Abstract: The disclosure provides methods and systems for evaluating formation geometry and petrophysical properties directly from raw electromagnetic measurements. The methods involve using a downhole tool to measure a property of a formation at multiple depths of investigation and calculating geometry and petrophysical property information by direct inversion from raw measurements acquired by the tool. The system includes a tool for measuring a formation property at different depths of investigation and a processor for calculating geometry and petrophysical information by direct inversion from the raw measurements acquired by the tool.

Abstract: Techniques involve obtaining dielectric measurements measured from a dielectric logging tool investigating a borehole at a one or more frequencies in a first frequency range, obtaining inductive measurements measured from an inductive tool investigating the borehole at one or more frequencies in a second frequency range, where the second frequency range is higher than the first frequency range, estimating an estimated resistivity anisotropy by conducting an inversion on the dielectric measurements, computing a measured resistivity anisotropy by conducting an inversion on the inductive measurements, and determining a characteristic related to reservoir fluids in the borehole, based on a comparison of the estimated resistivity anisotropy and the measured resistivity anisotropy.

Abstract: Methods and systems for determining petrophysical parameters of a formation are provided. In one embodiment, a method includes acquiring formation data with a borehole imaging tool deployed in a well penetrating a formation and acquiring additional formation data with a dielectric logging tool deployed in the well. The method also includes calibrating the formation data acquired with the borehole imaging tool based on the additional formation data acquired with the dielectric logging tool. The calibrated formation data can then be used in determining a petrophysical parameter of the formation. Additional methods, systems, and devices are also disclosed.

Abstract: A logging method and a logging tool for approximating a logging tool response in a layered formation are provided. The method includes obtaining a first layered profile of at least one first measurement log provided by a logging tool using a squaring process, obtaining a filtered measurement log from the first layered profile using a forward physical model for the logging tool, and estimating an approximation of the forward physical model using a parameterized function so as to provide a first logging tool response.

Abstract: Techniques involve obtaining dielectric measurements measured from a dielectric logging tool investigating a borehole at a one or more frequencies in a first frequency range, obtaining inductive measurements measured from an inductive tool investigating the borehole at one or more frequencies in a second frequency range, where the second frequency range is higher than the first frequency range, estimating an estimated resistivity anisotropy by conducting an inversion on the dielectric measurements, computing a measured resistivity anisotropy by conducting an inversion on the inductive measurements, and determining a characteristic related to reservoir fluids in the borehole, based on a comparison of the estimated resistivity anisotropy and the measured resistivity anisotropy.

Abstract: A downhole tool and method for determining properties of a formation. The method comprising irradiating the formation with a nuclear source; performing both a resistivity and a sigma measurement at each of different radial depths into the formation with a plurality of detectors; and inputting the measurements into a predetermined model for determining the properties of the formation.

Abstract: The disclosure provides methods and systems for evaluating formation geometry and petrophysical properties directly from raw electromagnetic measurements. The methods involve using a downhole tool to measure a property of a formation at multiple depths of investigation and calculating geometry and petrophysical property information by direct inversion from raw measurements acquired by the tool. The system includes a tool for measuring a formation property at different depths of investigation and a processor for calculating geometry and petrophysical information by direct inversion from the raw measurements acquired by the tool.

Abstract: The disclosure provides methods and systems for improving the interpretation of formation evaluation measurements. The methods involve using a downhole tool to measure a property of a formation at multiple depths of investigation and calculating a spatial integrated J function, a spatial integrated K function, or both from the measurements. The J function and K function are used in different applications to improve interpretation. The system includes a tool for measuring a formation property and a processor for calculating a spatial integrated J function, a spatial integrated K function from the measurements taken at different depths of investigation. The processor may also perform interpretations such as classifications, probability distributions and initialization steps for radial inversion using the J and K functions.

Abstract: A logging method and a logging tool for approximating a logging tool response in a layered formation are provided. The method includes obtaining a first layered profile of at least one first measurement log provided by a logging tool using a squaring process, obtaining a filtered measurement log from the first layered profile using a forward physical model for the logging tool, and estimating an approximation of the forward physical model using a parameterized function so as to provide a first logging tool response.

Abstract: An apparatus for determining a property of a downhole formation, the apparatus comprising: an array having a plurality of transmitters and receivers capable of propagating electromagnetic waves through the formation; measuring circuitry for measuring an effect of the formation on the propagating waves; control circuitry arranged to vary the propagating waves as a function of at least one of frequency, spacing and polarization; and processing circuitry arranged to combine the effects of the propagating waves that are varied according to frequency, spacing and polarization for determining the property of the downhole formation.

Abstract: A downhole tool and method for determining properties of a formation. The method comprising irradiating the formation with a nuclear source; performing both a resistivity and a sigma measurement at each of different radial depths into the formation with a plurality of detectors; and inputting the measurements into a predetermined model for determining the properties of the formation.

Abstract: An apparatus for determining a property of a downhole formation, the apparatus comprising: an array having a plurality of transmitters and receivers capable of propagating electromagnetic waves through the formation; measuring circuitry for measuring an effect of the formation on the propagating waves; control circuitry arranged to vary the propagating waves as a function of at least one of frequency, spacing and polarization; and processing circuitry arranged to combine the effects of the propagating waves that are varied according to frequency, spacing and polarization for determining the property of the downhole formation.

Abstract: A method of determining the porosity and fluid saturation for a given volume of an underground formation through which a borehole is drilled, the method comprising: measuring, from within the borehole, parameters relating to characteristics of the underground formation; determining volumetric values for resistivity, hydrogen index, density and neutron capture cross-section for the given volume from the measured parameters, each volumetric value including a contribution from formation matrix, water, oil and gas; determining, from the volumetric values, the volumes of rock matrix, pore water, oil and gas, and the salinity of the pore water; and determining the porosity and fluid saturation of the volume of the formation from the determined volumes and salinity.

Abstract: The invention concerns a method for determining the resistivity in a formation crossed by a cased well, in which one carries out at least one resistivity log in the cased well and one uses the results of at least one resistivity log in the non-cased well, carried out in the same well previously, in order to, in at least one zone (10) of the formation in which the resistivity has not changed between the cased and non-cased condition, deduce the value of a geometric factor k conditioning the resistivity and for determining, by means of said geometric factor k and the log in the cased well, the resistivity in at least one zone (11) different to the calibration zone, in which the resistivity has varied between the non-cased condition and the cased condition.

Abstract: A method of determining the porosity and fluid saturation for a given volume of an underground formation through which a borehole is drilled, the method comprising: measuring, from within the borehole, parameters relating to characteristics of the underground formation; determining volumetric values for resistivity, hydrogen index, density and neutron capture cross-section for the given volume from the measured parameters, each volumetric value including a contribution from formation matrix, water, oil and gas; determining, from the volumetric values, the volumes of rock matrix, pore water, oil and gas, and the salinity of the pore water; and determining the porosity and fluid saturation of the volume of the formation from the determined volumes and salinity.

Abstract: Methods for evaluating the properties of formations surrounding a borehole, include the steps of measuring electrical properties of the formation from within the borehole; deriving a model of parameters of the formation surrounding the borehole; and estimating the properties of the formation using the model to interpret the measured electrical properties. In one aspect of the invention in which the formation includes a series of distributed beds, each bed having specific properties. Another aspect includes grouping similar beds, assigning one or more properties to all of the beds in a group, and using the assigned properties to estimate the properties of the formation for measurements relating to the beds of that group. Another aspect includes making several different measurements of formation electrical properties and simultaneously estimating the formation properties from the different measurements to provide a joint inversion.

Abstract: Process for determining the resistivity (Rt) of a formation (9) surrounding a well (10) equipped with a casing (11) consisting of several casing segments (11.i, 11.

Abstract: The invention concerns a method for determining the resistivity in a formation crossed by a cased well, in which one carries out at least one resistivity log in the cased well and one uses the results of at least one resistivity log in the non-cased well, carried out in the same well previously, in order to, in at least one zone (10) of the formation in which the resistivity has not changed between the cased and non-cased condition, deduce the value of a geometric factor k conditioning the resistivity and for determining, by means of said geometric factor k and the log in the cased well, the resistivity in at least one zone (11) different to the calibration zone, in which the resistivity has varied between the non-cased condition and the cased condition.

Abstract: Process for determining the resistivity (Rt) of a formation (9) surrounding a well (10) equipped with a casing (11) consisting of several casing segments (11.i, 11.