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6040696 |
Method for estimating pore structure in carbonates from NMR measurements
In this invention a new interpretation methodology has been developed. A pore structure model is used to compute the relaxation behavior. This model is then used as the kernel of a best-fit...
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6031373 |
Nuclear magnetic resonance imaging process and device
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6026560 |
High pressure magnet assembly
The present invention provides a magnet assembly capable of operating in high temperature and pressure environments without delaminating. A low viscosity resin having a low glass transition...
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6023163 |
Well logging method and apparatus for determining gas and diffusion coefficient using NMR
In a method for determining the presence of gas in a region of investigation of earth formations surrounding a borehole. A movable logging device is used to generate two sequences of magnetic field...
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6023164 |
Eccentric NMR well logging apparatus and method
A method and apparatus are described using nuclear magnetic resonance (NMR) measurements for obtaining information relating to properties of geologic structures in highly conductive borehole...
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6023162 |
Three-dimensional morphology by magnetic resonance imaging
Methods and systems obtain three-dimensional images of object morphology using nuclear magnetic resonance imaging. Most preferably, an object is immersed in a volume of imaging fluid. An image is...
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6018243 |
NMR well logging apparatus and method
A nuclear magnetic resonance well logging apparatus including a magnet for inducing a static magnetic field in a substantially cylindrically shaped sector located in earth formations penetrated by...
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6008645 |
Prediction of permeability from capillary pressure curves derived from nuclear magnetic resonance pore size distributions
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...
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6008646 |
Apparatus for protecting a magnetic resonance antenna
The instruments of a pulsed nuclear magnetic resonance device are included in a drill collar for evaluating earth formations. The resulting tool makes NMR measurements through an electrically...
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6005389 |
Pulse sequences and interpretation techniques for NMR measurements
An NMR pulse sequence and signal processing method is disclosed for measurement of fast decay response signals from materials containing a fluid state. The proposed pulse sequence and processing...
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5994901 |
Magnetic resonance logging instrument
A magnetic resonance logging instrument is provided. The magnetic resonance logging instrument (10) may comprise a superconducting magnet system (12) operable to produce a static magnetic field and...
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5977768 |
Nuclear magnetic resonance logging with azimuthal resolution
Apparatus and method are disclosed for determining a nuclear magnetic resonance property of formations surrounding a borehole while drilling the borehole with a rotating drill bit on a drill...
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5969527 |
Rf coil assembly
An rf coil assembly for use in an NMR investigation, the assembly comprising (1) a transmitter coil (10) adapted to transmit an rf magnetic field suitable for the NMR investigation into a...
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5959453 |
Radial NMR well logging apparatus and method
A nuclear magnetic resonance sensing apparatus, including a magnet for inducing a static magnetic field within materials to be analyzed. The magnetic field is substantially coaxial with a...
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5923167 |
Pulsed nuclear magnetism tool for formation evaluation while drilling
A logging-while-drilling tool contains a pulsed nuclear magnetic resonance (NMR) device for evaluating earth formations. An antenna of the pulsed NMR device is electromagnetically coupled with a...
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5914598 |
Pulsed nuclear magnetism tool for formation evaluation while drilling
A permanent magnet of a pulsed nuclear magnetic resonance (NMR) device is positioned within a drill collar for evaluating earth formations. In this way, the torsional and bending strengths of the...
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5838155 |
Underground formation producibility and water cut from nuclear magnetic resonance data using an isolated pore
Potential producibility and the proportion of water and oil produced can be predicted for hydrocarbon bearing reservoirs using an isolated pore model and nuclear magnetic resonance data. The model...
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5831433 |
Well logging method and apparatus for NMR and resistivity measurements
A method is disclosed for determining a nuclear magnetic resonance characteristic and the resistivity of earth formations surrounding a borehole, including the following steps: passing a logging...
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5828214 |
Method and apparatus for resistivity determination by nuclear magnetic resonance measurement
An apparatus for measuring conductivity of earth formations penetrated by a wellbore including a magnet for inducing a static magnetic field in the earth formations penetrated by the wellbore. The...
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5814988 |
Combination nuclear magnetic resonance and electromagnetic induction resistivity well logging instrument and method
An apparatus for measuring induction resistivity and nuclear magnetic resonance properties of earth formations penetrated by a wellbore. The apparatus includes a magnet for inducing a static...
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5796252 |
Nuclear magnetic resonance borehole logging apparatus and method for ascertaining a volume of hydrocarbons independent of a diffusion coefficient
A nuclear magnetic resonance (NMR) logging technique reveals the volume of hydrocarbons in an earth formation. The differences in viscosity among gas, oil and water are used to distinguish among...
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5764058 |
Signal processing method for determining the number of exponential decay parameters in multiexponentially decaying signals and its application to nuclear magnetic resonance well logging
A method of determining the number of exponential decay modes in spin echo amplitude signals from a nuclear magnetic resonance well logging instrument. The method includes dividing the time...
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5757186 |
Nuclear magnetic resonance well logging apparatus and method adapted for measurement-while-drilling
A nuclear magnetic resonance sensing apparatus including a magnet for inducing a static magnetic field in materials to be analyzed, the magnetic field having uniform field strength around, being...
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5739687 |
Magnetic field generating assembly
A magnetic field generating assembly for use in NMR apparatus comprises a pair of first magnets arranged coaxially with like poles facing each other and axially spaced apart. At least one second...
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5710511 |
Method and apparatus for eddy current suppression
An electromagnetic wellbore logging tool including an elongated sonde adapted for traversing the wellbore, a source of alternating current, an antenna connected to the source of alternating...
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5698979 |
Method for NMR diffusion measurement
A method of measuring motion properties of nuclei within pore spaces of a porous medium. The method includes applying a static magnetic field to the medium to polarize the nuclei, generating a...
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5696448 |
NMR system and method for formation evaluation using diffusion and relaxation log measurements
A simple, pore-level model for diffusion and NMR relaxation of oil-water mixtures in water wet pores has been developed. In addition to lending physical insight into the relaxation time behavior of...
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5681753 |
Solution containing a nitroxide radical for magnetometry by nuclear magnetic resonance
The invention relates to a solution containing a nitroxide radical for magnetometry by nuclear magnetic resonance. This solution is constituted by a nitroxide radical of formula: ##STR1## in which...
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5680044 |
Oscillating magnetic field generating assembly
A nuclear magnetic resonance apparatus having a magnetic assembly which generates a main static field in a working region which is external of the magnetic assembly. The main static magnetic field...
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5680043 |
Nuclear magnetic resonance technique for determining gas effect with borehole logging tools
An NMR pulse sequence technique for use in the borehole environment is provided which uses CPMG pulses according to W i -90-(t cp -180-t cp -echo) j ! i where j is the index of the CPMG...
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5646528 |
Magnet assembly
A magnet assembly having a pair of substantially aligned, spaced apart first magnets having like poles facing each other; and one or more auxiliary magnets axially aligned with the first magnets...
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5644231 |
High pressure magnetic antenna assembly
The present invention provides an antenna assembly capable of operating in high temperature and pressure environments without delaminating. In this antenna assembly, the ferrites are separately...
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5596274 |
Determining bound and unbound fluid volumes using nuclear magnetic resonance pulse sequences
A borehole logging tool comprises a Nuclear Magnetic Resonance (NMR) tool and is pulsed according to a selected Carr Purcell-Meiboom Gill (CPMG) sequence. Because the recovery time between CPMG...
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5585720 |
Signal processing method for multiexponentially decaying signals and application to nuclear magnetic resonance well logging tools
A method of reducing bias error in nuclear magneic resonance (NMR) spin-echo signals. The method includes filtering the signals using a filter having a bandwidth inversely related to the length of...
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5565775 |
Producible fluid volumes in porous media determined by pulsed field gradient nuclear magnetic resonance
The present invention is a method to determine the bound and free fluid index of fluids in porous media by pulsed field gradient (PFG) NMR diffusion measurements. The PFG NMR signal is evaluated...
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5557200 |
Nuclear magnetic resonance determination of petrophysical properties of geologic structures
An improved system for using magnetic resonance techniques to obtain information relating to geologic structures is disclosed. The system of the present invention uses values of the total porosity...
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5557201 |
Pulsed nuclear magnetism tool for formation evaluation while drilling
The instruments of a pulsed nuclear magnetic resonance (NMR) device are included in a drill collar for evaluating earth formations. The resulting tool makes NMR measurements while the formation is...
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5539309 |
Method and apparatus for sample monitoring
Method and apparatus for monitoring a sample having `solid` and `liquid` content using a magnetic field generator and subjecting the sample to a static magnetic field in the first direction to...
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5528143 |
Loop oscillator NMR probe
A nuclear magnetic resonance probe is provided comprising a high frequency resonator (14, 16) having a resonant frequency, a first coaxial conductor (20) connected to the high frequency resonator,...
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5525904 |
Determination of rock core characteristics
An apparatus for monitoring characteristics of rock cores using NMR. The apparatus is provided with a clad permanent magnet for generating a magnetic field having a saddle profile. The magnetic...
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5517115 |
Efficient processing of NMR echo trains
A method and apparatus is disclosed for efficient processing of nuclear magnetic resonance (NMR) echo trains in well logging. Apriori information about the nature of the expected signals is used to...
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5512825 |
Method of minimizing dead-periods in magnetic resonance imaging pulse sequences and associated apparatus
A method of minimizing dead-periods in magnetic resonance imaging pulse sequences employs a specimen disposed within magnetic field, a source of RF signals, a receiver for receiving signals from...
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5488342 |
Magnet assembly for NMR
A magnet assembly comprises a pair of substantially aligned, spaced apart first magnets (1,2) having like poles facing each other. A second magnet (3) is positioned adjacent the space between the...
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5486762 |
Apparatus including multi-wait time pulsed NMR logging method for determining accurate T2-distributions and accurate T1/T2 ratios and generating a more accurate output record using the updated T2-distributions and T1/T2 ratios
When a pulsed nuclear magnetic resonance (NMR) well logging tool is traversing a wellbore, a NMR well logging method includes magnetizing the hydrogen nuclei in a formation traversed by the tool...
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5486761 |
Nuclear magnetic resonance measuring apparatus
The disclosure invention is directed to a nuclear magnetic resonance measurement apparatus that can be utilized in a logging device which operates generally centrally in a borehole, and has a...
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5463318 |
Differential resonance magnetometer
A differential resonance magnetometer, which includes a reference assembly and at least one measurement assembly. A polarization current is produced by the reference assembly is the same as a...
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5451873 |
Method and apparatus for determining the in situ larmor frequency of a wellbore NMR tool to compensate for accumulation of magnetic material on the magnet housing of the tool
A system includes a wellbore tool disposed in a wellbore and a surface apparatus disposed at a surface of the wellbore. Prior to operating the tool to take an initial measurement, the wellbore tool...
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5432446 |
Borehole measurement of NMR characteristics of earth formation
NMR logging apparatus is provided which produces a strong, static and homogeneous magnetic field B 0 in a Volume of an adjacent formation on one side of the tool to measure nuclear magnetic...
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5428291 |
Determination of fluid transport properties in porous media by nuclear magnetic resonance measurements of fluid flow
The present invention is a method to determine fluid transport properties of porous media by nuclear magnetic resonance measurements of fluid flow. The NMR signal is encoded by the fluid flow...
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5389877 |
Nuclear magnetic resonance pulse sequences for determining bound fluid volume
An NMR pulse sequence for use in a borehole logging tool includes a series of CPMG pulses according to: T r -90° ±x -(t cp -180° y -t cp -echo j ) where j is the index of CPMG echoes...
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