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6088655 |
Electrical resistance tomography from measurements inside a steel cased borehole
Electrical resistance tomography (ERT) produced from measurements taken inside a steel cased borehole. A tomographic inversion of electrical resistance measurements made within a steel casing was...
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6088656 |
Method for interpreting carbonate reservoirs
An integrated interpretation methodology is described that evaluates carbonate reservoirs. The methodology consists of first classifying the rock facies. A geometrical model specific to the...
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6060884 |
Method and apparatus for measuring electromagnetic properties of materials in borehole environs and simultaneously determining the quality of the measurements
A wave propagation measurement-while-drilling system is used to measure selected formation and borehole parameters of interest and simultaneously provide indications of the quality of the selected...
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6044325 |
Conductivity anisotropy estimation method for inversion processing of measurements made by a transverse electromagnetic induction logging instrument
A method for generating an improved estimate of horizontal conductivity, dip angle, azimuth and anisotropy parameter of an earth formation penetrated by a wellbore from dual-frequency transverse...
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6020741 |
Wellbore imaging using magnetic permeability measurements
A wellbore imaging tool is provided which is sensitive to magnetic permeability changes in the wellbore wall. In one embodiment, the measuring array comprises a transmitter coil, an array of...
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5999884 |
Method for determining the axial position of formation layer boundaries using measurements made by a transverse electromagnetic induction logging instrument
A method for estimating axial positions of formation layer boundaries from transverse electromagnetic induction signals. A first derivative is calculated with respect to depth of the induction...
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5999883 |
Conductivity anisotropy estimation method for inversion processing of measurements made by a transverse electromagnetic induction logging instrument
A method for determining an initial estimate of the horizontal conductivity and the vertical conductivity of an anisotropic earth formation. Electromagnetic induction signals induced by induction...
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5987386 |
Interpolation of induction tool response using geometrical factors as basis functions
A method for estimating the apparent conductivity of a formation comprises the steps of: providing layer conductivity data over a range of points in the formation outside the borehole along a...
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5966013 |
Determination of horizontal resistivity of formations utilizing induction-type logging measurements in deviated borehole
A method for determining horizontal resistivity of an anisotropic formation and a formation anisotropy response factor with an induction logging tool is claimed. The method utilizes two differing...
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5960370 |
Method to determine local variations of the earth's magnetic field and location of the source thereof
A method to determine the earth's magnetic field vector along a sub-surface wellpath having unknown and possibly changing azimuth, in the presence of a magnetic disturbance caused by a magnetic...
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5884227 |
Method for interpreting induction logs in high resistivity contrast earth formations
A method of adjusting induction receiver signals for skin effect in an induction logging instrument including a plurality of spaced apart receivers and a transmitter generating alternating magnetic...
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5883515 |
Method of determining formation resistivity utilizing combined measurements of inductive and galvanic logging instruments
A method of determining selected parameters of an earth formation surrounding a borehole by first, obtaining at least one induction logging measurement of the selected parameters in a first...
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5878372 |
Method for simultaneous inversion processing of well log data using a plurality of earth models
A method of determining a plurality of formation models each of which will simulate the response of a well logging instrument. A measured response of the well logging instrument is used to generate...
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5870690 |
Joint inversion processing method for resistivity and acoustic well log data
A method of joint inversion processing acoustic velocity and electrical resistivity well log data. The method includes generating an initial model of earth formations over an interval of interest....
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5867806 |
System and method for performing inversion on LWD resistivity logs with enhanced resolution
A system and method for performing inversion and for correcting for shoulder bed effect. The method enhances the resolution of wave propagation resistivity logs and corrects the logs for adjacent...
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5854991 |
Method for inversion processing of transverse electromagnetic induction well logging measurements
A method for determining the 2-dimensional distribution of horizontal and vertical electrical conductivities of earth formations surrounding a wellbore using measurements made by a transverse...
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5835882 |
Method for determining barriers to reservoir flow
A method and apparatus for predicting barriers to fluid flow in a subterranean reservoir using well data and 3-D seismic data are disclosed, where a preferred first step in the method models...
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5835883 |
Method for determining distribution of reservoir permeability, porosity and pseudo relative permeability
A method and apparatus for predicting distribution of reservoir permeability or porosity and pseudo relative permeability using well data and 3-D seismic data are disclosed, where a preferred first...
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5781436 |
Method and apparatus for transverse electromagnetic induction well logging
A method of measuring the conductivity of earth formations penetrated by a wellbore. The method comprises selectively passing an alternating current through transmitter coils inserted into the...
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5703772 |
Method and apparatus for correcting drift in the response of analog receiver components in induction well logging instruments
A method of determining amplitude and phase response of a receiver amplifier in an induction well logging instrument including the steps of generating an oscillating current at least one frequency,...
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5703773 |
Real-time 2-dimensional inversion process and its application to induction resistivity well logging
The invention is a method of inversion processing signals from an induction well logging instrument including a transmitter and a plurality of receivers at spaced apart locations. The method...
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5698982 |
Method and system for skin effect correction in a multiple transmit frequency induction logging system
An induction logging tool is disclosed for utilization in conjunction with surface electronic equipment for measuring a characteristic of subsurface formations. A transmit signal which is comprised...
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5682099 |
Method and apparatus for signal bandpass sampling in measurement-while-drilling applications
A logging apparatus is provided for use in a wellbore for measuring an attribute of at least one of the wellbore and a surrounding formation, when coupled to a wellbore tubular expended in the...
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5666057 |
Method of skin effect correction and data quality verification for a multi-frequency induction well logging instrument
A method of correcting receiver signals in an induction well logging instrument for skin effect. The method includes determining a magnitude of signals induced in an induction receiver at each one...
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5656930 |
Method for determining the anisotropic properties of a subterranean formation consisting of a thinly laminated sand/shale sequence using an induction type logging tool
Formation anisotropic properties are determined using knowledge of the borehole dip angle and an induction logging instrument to obtain two formation derived resistivities. Separate shale layer...
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5585727 |
Apparatus for measuring resistivity of an earth formation using delta-sigma digital signal generation and sigma-delta digital detection system
An apparatus for measuring resistivity of an earth formation. The apparatus includes at least one source of measuring current. The source includes a delta-sigma modulator and a serial bit source...
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5469062 |
Multiple depths and frequencies for simultaneous inversion of electromagnetic borehole measurements
A wave propagation measurement-while-drilling system is used to determine selected formation and borehole properties. One or more transmitter-receiver pairs are utilized with the transmitter...
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5463549 |
Method and apparatus for determining permeability of subsurface formations
Characteristics of invasion profiles exhibiting effects of gravity, and particularly their manifestations on resistivity logs of a plurality of different radial depths of investigation, are used to...
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5448171 |
Method for variable radial depth induction log
The present disclosure is directed to a method of obtaining a different radial depth of investigation from an induction log. A typical induction log is moved along a well borehole to obtain two...
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5446654 |
Shoulder effect logging method
In a resistivity log, a curve is obtained showing the values of resistivity where adjacent beds impact the measured resistivity. The curve as a function of well depth is first converted into a...
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5379216 |
Method and apparatus for producing a new output record medium illustrating a quantitative description in the volume dimension of mud filtrate invasion into permeable zones of a formation in a wellbore
A volume transform system, which includes a computer processor and a novel volume transform software, receives a set of invasion parameters from a parameterization system, the parameterization...
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5373443 |
Method for imaging with low frequency electromagnetic fields
A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy...
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5349528 |
Method apparatus for determination of porosity lithological composition
Evaluation of thinly laminated shaly sand reservoirs has long been one of the most difficult problems of log analysis. A primary reason is that only shallow shale indicators such as a Dipmeter,...
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5345179 |
Logging earth formations with electromagnetic energy to determine conductivity and permittivity
A form of the disclosure is directed to determining properties of formations surrounding an earth borehole having a standoff layer. A method is disclosed for determining the conductivity and...
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5329448 |
Method and apparatus for determining horizontal conductivity and vertical conductivity of earth formations
The disclosed technique and apparatus utilizes the different characteristic responses of a plurality of signals from a propagation or induction well logging device to determine the vertical and...
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5305212 |
Alternating and static magnetic field gradient measurements for distance and direction determination
Magnetic field gradient sensing apparatus utilizing highly sensitive fluxgate magnetometers permit direct determination of the distance between two well bores and for determining the direction from...
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5299359 |
Method and system for measurement of internal tube dimensions within a wellbore
A caliper logging sonde is provided having a plurality of sensing fingers each of which is pivotally mounted to the sonde and movable with respect to the sonde in response to variations in the...
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5243521 |
Width determination of fractures intersecting a borehole
The present invention is directed to utilizing data indicative of formation resistivity and calculating the width and depth of a fracture therefrom. In the preferred embodiment, the present...
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5233522 |
Multifrequency dielectric logging tool including antenna system responsive to invaded rock formations
An apparatus for induction logging is disclosed. By transmitting a sequence of pulses at many frequencies, the formation invaded zone diameter can be distinguished as a result of changes in...
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5210691 |
Method and apparatus for producing a more accurate resistivity log from data recorded by an induction sonde in a borehole
A maximum entropy method (MEM) determines a more accurate formation parameter profile, such as conductivity profile, of a formation. The MEM method employs an iterative procedure for determining...
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5196698 |
Method and apparatus for nuclear logging using lithium detector assemblies
A method and apparatus for nuclear logging, and in particular, neutron porosity logging is presented. In accordance with the present invention, a pair of spaced lithium detectors, preferably Li 6 ...
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5187661 |
Method of determining invaded formation properties including resistivity dielectric constant and zone diameter
An apparatus and method for induction logging is disclosed. By transmitting a sequence of pulses at many frequencies, the formation invaded zone diameter can be distinguished as a result of changes...
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5184079 |
Method and apparatus for correcting data developed from a well tool disposed at a dip angle in a wellbore to eliminate the effects of the dip angle on the data
In a well logging truck computer which phroduces an induction log, a dip correction algorithm, stored in a memory of the computer, corrects an error introduced in the induction log by dip effect....
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5157605 |
Induction logging method and apparatus including means for combining on-phase and quadrature components of signals received at varying frequencies and including use of multiple receiver means associated with a single transmitter
Induction logging apparatus is disclosed which depends for its operation not only upon its arrangement of coils, but also upon the skin depth of the formation. The skin effect of the formation is...
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5146167 |
Method and apparatus for determining the conductivity of subsurface earth formations by filtering and summing in-phase and quadrature conductivity signals with correction values
An improved induction well logging processing technique for determining conductivity measurements of subsurface earth strata. An in-phase conductivity signal and a quadrature conductivity signal...
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5144245 |
Method for evaluating a borehole formation based on a formation resistivity log generated by a wave propagation formation evaluation tool
The method evaluates borehole formations using corrected formation resistivity logs obtained from a formation evaluation tool. In accordance with the present invention the method corrects the error...
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5142472 |
Method of measuring the resistivity and thickness of a thin underground layer using induction logging
A method used for determining true in-situ resistivity of a thin layer within a formation from dual induction log data. The method calculates true resistivity without the existing need: 1) for an...
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5086224 |
Analysis of nuclear data for determining characteristics of earth formations traversed by a borehole
A method for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising detecting gamma rays or neutrons representative of the formations and forming...
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5075625 |
Procedure and device for the detection of inversions of the earth's magnetic field by means of measurement taken in a drill shaft
A method and device for detecting inversions of the earth's magnetic field by taking measurements in a drill shaft. The device includes a first probe used to measure the magnetic induction B 1 ...
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5041975 |
Borehole correction system for an array induction well-logging apparatus
A new borehole correction software, for use in a well logging truck computer, obtains an accurate measurement of the true conductivity of a formation in a borehole by subtracting a correction term,...
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