Matches 151 - 200 out of 402 < 1 2 3 4 5 6 7 8 9 >
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6586932 Enhanced performance antennas for NMR logging  
An antenna design for a downhole nuclear magnetic resonance logging tool is enhanced to shape the resultant RF field generated by the antenna. The enhancement is accomplished by adding additional...
6586931 NMR logging in the earth's magnetic field  
An apparatus and a method for measurement of NMR relaxation parameters of earth formations uses a coil on a logging tool to substantially polarize nuclear spins within a volume of earth. The...
6580273 Side-looking NMR probe for oil well logging  
A side-looking NMR logging tool incorporates a permanent magnet arrangement having a magnetization direction oriented towards a side of the tool and a dipole RF antenna displaced towards the front...
6580272 Nuclear magnetic resonance logging based on steady-state free precession  
Nuclear magnetic resonance logging methods that detect and analyze a steady state free precession (SSFP) signal are described. In some embodiments, Carr-Purcell-Meiboom-Gill (CPMG) spin echoes are...
6577125 Temperature compensated magnetic field apparatus for NMR measurements  
An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175°...
6573716 Method and apparatus for tuning an NMR coil  
A downhole controller is used to tune the resonance frequency of an antenna after each NMR measurement sequence. At the end of the sequence, the downhole controller causes a pulse sequencer to...
6573715 Porosity and permeability measurement of underground formations containing crude oil, using EPR response data  
A method and apparatus ( 10 ) for detecting and measuring the amount of crude oil in underground rock formations. EPR measurements are used to calculate the amount of crude oil, and may be...
6571619 Real time petrophysical evaluation system  
A subsurface formation petrophysical evaluation method including: determining formation porosity and permeability using a quantitative indication of formation composition; estimating water-filled...
6570381 Nuclear magnetic resonance well logging method and apparatus  
The present invention relates generally to a nuclear magnetic resonance apparatus and method for substantially eliminating the effects of phase coherent acoustic ringing in borehole logging. A...
6566874 Detecting tool motion effects on nuclear magnetic resonance measurements  
An NMR measurement apparatus is potentially subject to relative motion between the apparatus and a sample. The measurement apparatus includes at least one magnet, at least one coil and circuitry...
6563314 Well logging method and apparatus for determining the nuclear magnetic resonance longitudinal magnetization decay of formations  
A method for determining the nuclear magnetic resonance longitudinal magnetization decay of formations surrounding an earth borehole that involves: providing a logging device moveable through the...
6559640 NMR apparatus and method utilizing pulsed static magnetic fields  
An apparatus and method for making NMR measurements uses an electromagnet for producing the static magnetic field. When used in well logging applications, the absence of a strong permanent magnet...
6559639 Estimating permeability without determinating a distribution of relaxation times  
A permeability estimation technique for use with spin echo signals that are received from a sample includes summing indications of the amplitudes of the spin echo signals. The results of the...
6549007 On-line NMR imaging of a solid or liquid object undergoing continuous translational motion  
A nuclear magnetic resonance imaging technique is applied to objects undergoing translational motion for analysis of objects on a conveyor passing through an imaging unit. The objects are passed...
6545471 Method for resistivity well logging utilizing nuclear magnetic resonance  
A method for determining petrophysical properties of geological structures using nuclear magnetic resonance utilizes a well logging apparatus and estimates resistivity in the formation surrounding...
6534980 Downhole NMR tool antenna design  
An NMR tool includes RF antennae and a cylindrical permanent magnet to establish a static magnetic B 0 field for performing the NMR measurement sequence. The magnetic field of the magnet is...
6525535 NMR apparatus for oil well logging of large and small diameter wells  
The invention is a method and apparatus for performing NMR measurements in MWD effective for large and small boreholes. The invention uses a magnet assembly to produce a generally oval static...
6525534 System and methods for NMR signal processing without phase alternated pair stacking  
A system and methods for improving the vertical resolution of NMR logs based on data acquisition methods and signal processing techniques that need not apply Phase Alternated Pair Stacking (PAPS)....
6522137 Two-dimensional magnetic resonance imaging in a borehole  
A downhole NMR measurement apparatus for use in a borehole includes at least one magnet, at least one RF transmission coil, at least one gradient coil and circuitry. The magnet(s) establish a...
6522136 Well logging technique and apparatus for determining pore characteristics of earth formations using magnetic resonance  
A method for determining a characteristic of formations surrounding an earth borehole, includes the following steps: (a) providing a logging device that is moveable through the borehole; (b)...
6522138 Resolution enhancement for sequential phase alternated pair nuclear magnetic resonance measurements  
A method for retrieving corrected individual measurements from a series of sequentially pairwise-combined measurements. The method includes providing an initial estimate for a first one of the...
6518755 Measurement technique and apparatus for high-resolution multi-volume NMR well logging  
Using phase-alternate pairs to eliminate the effects of ringing requires a large running average for multi-frequency NMR logging tools. At logging speeds greater than about five ft/min, the...
6518757 Use of CPMG sequences with phase cycled refocusing pulses in inside-out NMR for phase encoded imaging and to eliminate coherent ringing within one scan  
A method for performing phase encoded inside-out magnetic resonance imaging. The phase of the nuclear spin is advanced by applying a magnetic field gradient between application of each of several...
6518754 Powerful bonded nonconducting permanent magnet for downhole use  
A transverse dipole NMR tool includes a non-conductive permanent magnet made of electrically conductive material such as SmCo. The concentration of SmCo is selected to be at a level low enough to...
6512371 System and method for determining oil, water and gas saturations for low-field gradient NMR logging tools  
A well logging system and method are disclosed for detecting the presence and estimating the quantity of gaseous and liquid hydrocarbons in the near wellbore zone. The system uses a gradient-based,...
6498484 Method for reducing ringing in nuclear magnetic resonance well logging instruments  
A method for reducing ringing in nuclear magnetic resonance measurements is disclosed. The method includes inducing a static magnetic field in a sensitive volume to orient nuclear magnetic spins of...
6489763 Magnet assembly for nuclear magnetic resonance well logging tools  
A magnet assembly for nuclear magnetic well logging apparatus includes two diametrically opposed magnets which produce a static and substantially homogeneous magnetic field. Each magnet has a...
6479994 Industrial on-line analysis by nuclear magnetic resonance spectroscopy  
A nuclear magnetic resonance spectroscopic technique is applied to objects undergoing translational motion for chemical analysis of objects on a conveyor passing through a detector module. The...
6477516 System and method for predicting parameter of hydrocarbon with spectroscopy and neural networks  
A method for predicting parameters of hydrocarbons includes the steps of generating an NMR spectrum of a sample of a hydrocarbon having different hydrogen or carbon types related to structures or...
6466013 Nuclear magnetic resonance measurements in well logging using an optimized rephasing pulse sequence  
A pulsed NMR tool has a magnet arrangement that is used to generate a static magnetic field having a substantially uniform field strength in a region of the formation surrounding the borehole. An...
6462542 Nuclear magnetic resonance measurements and methods of analyzing nuclear magnetic resonance data  
Nuclear magnetic resonance measurements on a fluid in a rock and methods of analyzing nuclear magnetic resonance data are described. At least one nuclear magnetic resonance measurement is...
6459262 Toroidal receiver for NMR MWD  
An NMR apparatus includes permanent magnets oppositely polarized in the axial direction and suitably arranged along the axis of the apparatus to produce a nearly radial static magnetic field in a...
6459992 Method and apparatus for determining logging tool displacements  
A method of determining the displacements of a logging tool during a measurement interval of the logging tool in a borehole includes obtaining a set of accelerometer signals corresponding to...
6452389 NMR pulse sequences for increasing the efficiency of acquisition  
A plurality of CPMG sequences is used to obtain NMR data with an instrument having a gradient magnetic with a constant resolution of T 2 . Different values of acquisition time (AT) are used for...
6452388 Method and apparatus of using soft non-ferritic magnetic material in a nuclear magnetic resonance probe  
The present invention provides a novel use of a powdered high saturation flux density soft magnetic material as a NMR probe core material. The probe structural geometry facilitates the use of...
6445307 Drill string telemetry  
A telemetry transmitter located in a portion of a drill string comprises an input for receiving and transmitting data obtained from at least one transducer arranged to sense a parameter of the...
6445180 Nuclear magnetic resonance tool with active RF spoiler antenna  
A novel nuclear magnetic resonance (NMR) probe design for operating in a bore hole to obtaining the NMR characteristics of a region of interest adjacent the bore hole, characterized by a main RF...
6437564 Estimate of transversal motion of the NMR tool during logging  
The static magnetic field of a permanent magnet used in an NMR tool moves with the tool. NMR measurements made with a moving tool are affected by incomplete polarization of the nuclear spins in the...
6429654 Nuclear magnetic resonance pulse sequence for improving signal-to-noise ratio  
A method for acquiring nuclear magnetic resonance measurements of a material uses a gradient tool. A modified CPMG sequence is used wherein the duration of the refocusing pulse is selected to...
6429653 Method and apparatus for protecting a sensor in a drill collar  
A method and apparatus for protecting a sensor from impact and abrasion while drilling a borehole including a drill collar having a section of electrically non-conductive material, such as a...
6420869 Method and apparatus for estimating NMR properties by near infrared spectra  
By developing correlations between near-infrared spectra (NIR) and the T 1 and T 2 Nuclear Magnetic Resonance (NMR) decay times of known crude oils, we can then use near-infrared measurements to...
6411087 NMR logging tool with Hi-Tc trap field magnet  
Trapped field magnets (TFMS) on an NMR logging tool are used to produce a static magnetic field in a formation surrounding a borehole. The TFMs are made of material having a high T c , so that the...
6400147 Downhole NMR tool having a programmable pulse sequencer  
An NMR logging tool includes at least one antenna and a pulse sequencer. The pulse sequencer is coupled to said at least one antenna and is adapted to receive state descriptors that are indicative...
6400148 Use of redundant data for log quality measurements  
In one embodiment of the invention, an induction logging system is used to measure selected formation and borehole parameters of interest and simultaneously provide indications of the quality of...
6400149 Nuclear magnetic resonance apparatus and method for generating an axisymmetric magnetic field having straight contour lines in the resonance region  
The present invention is directed to a nuclear magnetic resonance apparatus and method for generating an axisymmetric magnetic field having long, straight contour lines in the resonance region. A...
6392409 Determination of T1 relaxation time from multiple wait time NMR logs acquired in the same or different logging passes  
Nuclear magnetic resonance measurements of a porous medium using multiple wait times are used for determining the longitudinal relaxation time T 1 time of oil in a hydrocarbon reservoir. The T 1 ...
6388441 Method for processing NMR data without phase-alternating-pair (PAP) averaging  
NMR data are acquired using a phase-alternation of the tipping pulse. Differences between consecutive samples acquired with same or different frequencies are determined and an average value of the...
6377042 Method and apparatus for merging of NMR echo trains in the time domain  
Proposed is a new method and system to obtain enhanced-resolution NMR data by merging, in the time domain, different NMR pulse echo trains into a single echo train. The input echo trains can be...
6373248 Nuclear magnetic resonance logging with azimuthal resolution  
The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The...
6369567 Nuclear magnetic resonance method and apparatus for determining pore characteristics of rocks and other porous materials  
A method for determining a pore characteristic of a substance includes the following steps: subjecting the substance to a substantially uniform static magnetic field; applying a magnetic pulse...
Matches 151 - 200 out of 402 < 1 2 3 4 5 6 7 8 9 >