Abstract: Systems and methods for generating a multi-dimensional distribution function. First data and second data may be received in response to one or more radiofrequency pulses that are transmitted into a subterranean formation. The first data may include Carr-Purcell-Meiboom-Gill data, and the second data may include diffusion editing data with initial echo spacings longer than subsequent echo spacings. The second data may be inverted. A multi-dimensional distribution function may be determined using the inverted second data.

Abstract: Estimating and displaying information about the size of molecules within a substance from nuclear magnetic resonance (NMR) maps and/or logs. Methods include utilizing a relationship between the molecular size (e.g., mean chain length), and either a moment of diffusion or a relaxation distribution, to create a scale on a two-dimensional map. In one case, applying the relationship between the molecular size, and either a moment of diffusion or a relaxation distribution, to one-dimensional diffusion or relaxation distributions for the purpose of estimating the mean chain length of molecules within the substance. In another case, a method includes determining mean chain lengths of molecules within a substance and providing a one-dimensional NMR log showing the mean chain lengths at a plurality of depths. In some cases, the NMR log includes actuatable regions for examining two-dimensional NMR maps or chain length distributions of the substance corresponding with distinct depths of the substance.

Abstract: Systems and methods for magic angle spinning nuclear magnetic resonance analysis of samples from unconventional reservoirs are described. Fast and inexpensive methods are described that can provide reliable information on TOC content, type, and maturity (via the relative abundances of different hydrocarbons, for example) without the need for more extensive sample preparation or destruction. If care is taken during sample recovery and storage, NMR can also yield an estimate of gas-in-place, including detailed typing (e.g. methane vs. ethane). The described MAS NMR analysis is used to determine various properties of unconventional reservoirs, including gas and oil shales, which are useful in evaluating their worth and producibility.

Abstract: A downhole tool includes a cylindrical housing. A magnet and an antenna may be positioned within the housing. An excluder may be positioned around the housing, and a thickness of the excluder may vary around the housing.

Abstract: Methods are disclosed for characterizing samples containing a plurality of molecular species through the use of multi-dimensional spectra obtained by processing of measurements resulting from pulse sequences combining NMR spectroscopy and NMR relaxation techniques.

Abstract: A magnetic resonance (MR) receiver is described herein. The MR receiver can be used to process nuclear magnetic resonance (NMR) signals. The MR receiver includes a transformer that amplifies the MR signals and a preamplifier that receives the MR signals from the transformer. The preamplifier can include a transimpedance amplifier circuit with an input stage that includes a field effect transistor.

Abstract: A coaxial nuclear magnetic resonance (NMR) probe and related methods are described herein. The coaxial NMR probe includes a housing with a fluid inlet, a fluid outlet, a longitudinal axis, and an interior volume. The housing contains a fluid sample that is analyzed by the probe. The coaxial NMR probe also includes an elongated conductor disposed along the longitudinal axis of the housing. The elongated conductor generates an oscillating electromagnetic field within the interior volume of the housing. The oscillating electromagnetic field produces a NMR signal within the fluid sample. The elongated conductor may also be used to receive this NMR signal. The NMR signal is then analyzed to determine information about the fluid sample. Various NMR pulse sequences for use with this coaxial probe and other coaxial probes are also described herein.

Abstract: Apparatus and methods for characterizing hydrocarbons in a subterranean formation including sending and measuring NMR signals; analyzing the signals to form a distribution; and estimating a property of a formation from the distribution, wherein the sending comprises pulse sequences configured for a formation pore size, and wherein the computing comprises porosity. Apparatus and methods for characterizing hydrocarbons in a subterranean formation including sending and measuring NMR signals; analyzing the signals to form a distribution; and estimating a property of a formation from the distribution, wherein the formation comprises a distribution of pore sizes of about 10 nm or more, and wherein the computing comprises natural gas composition.

Abstract: A hydrocarbon sample is subjected to a chemically selective J-editing nuclear magnetic resonance (NMR) pulse sequence. Resulting signals are analyzed in order to identify a coupling frequency present in at least one molecule of the hydrocarbon sample. A J-coupling frequency of approximately 150 Hz is indicative of a component having an internal double bonded carbon atom (i.e., an olefin). The presence of an olefin in a hydrocarbon sample can be indicative of the presence of a synthetic based mud (SBM) in the sample.

Abstract: An NMR apparatus disposed in a wellbore and having an array of two or more NMR sensors located at substantially the same axial position on the NMR apparatus and having different directional sensitivities is used to acquire an NMR signal from at least two of the two or more NMR sensors. The NMR signals are combined to obtain borehole information. The borehole information may include an azimuthal image of the formation surrounding the borehole. The azimuthal image may be a formation porosity image, a formation bound fluid image, a T2 distribution image, a T2 log mean image, a formation permeability image, or a formation fluid viscosity image. If two or more pre-amplifiers and receiver circuitry are also provided, the NMR signals may be combined prior to passing through the pre-amplifiers and receiver circuitry to improve the signal to noise ratio of the total signal from the desired sample space.

Abstract: Methods and apparatuses are provided for analyzing a composition of a hydrocarbon-containing fluid. The methods include using a nuclear magnetic resonance (NMR) tool to conduct an NMR measurement on the hydrocarbon-containing fluid to obtain NMR data. A non-NMR tool, such as an optical tool, is used to conduct additional measurements on the hydrocarbon-containing fluid and to obtain non-NMR data on the fluid. An indication of the composition of the fluid can be determined by using the NMR data and the non-NMR data in an inversion process.

Abstract: Methods and related systems are described for extracting information about a system of nuclear spins including: performing a plurality of Nuclear Magnetic Resonance (NMR) measurements on the system of nuclear spins; acquiring NMR data from each of the plurality of NMR measurements; performing data inversion using an random-sampler to generate an ensemble of spectra so as to extract information about the system of nuclear spins; and analyzing the performed random-sampler inversion results to extract information about the system of nuclear spins.

Abstract: A method and system for determining a property of a substance using nuclear magnetic resonance (NMR) is described herein. The method includes applying a NMR pulse sequence to the substance. The NMR pulse sequence includes a first set of pulses and a second set of pulses. The first set of pulses and the second set of pulses encode for overlapping diffusion times. By overlapping diffusion times, the NMR pulse sequence can be used to measure a diffusion coefficient for a first diffusion time, a diffusion coefficient for a second diffusion time, and a correlation between the two overlapping diffusion times. This information, in turn, can be used to differentiate between intrinsic bulk diffusivity of the substance and the reduced diffusivity of the substance caused by restricted diffusion.

Abstract: A non-resonant transmitter for a magnetic resonance (MR) system, such as a nuclear magnetic resonance (NMR) system, is described herein. The transmitter includes a coil for applying NMR pulse sequences to a substance. The coil is coupled to a circuit that includes a capacitor, a number of switches, and a power source. The transmitter operates in two modes. In a charging mode, the switches decouple the coil from the capacitor and the capacitor is charged by the power source. In a discharging mode, a radio frequency pulse is generated and the switches couple and decouple the coil from the capacitor so that the capacitor provides power to the coil. The addition of the capacitor improves the power factor of the circuit and reduces power draw from the power source.

Abstract: A formation fluid sample is analyzed using NMR spectroscopy to obtain a NMR spectrum. The NMR spectrum is then analyzed to find evidence of the amount of olefins present in the sample. The amount of olefins present in the sample can then be correlated to the level of contamination of the sample. In one embodiment, a 1H chemical shift of between substantially 4.5 and 6 ppm is used to identify olefins present in the sample. In another embodiment, a 1H chemical shift of substantially 1.9 to 2.1 ppm is used to identify olefins present in the sample. The NMR spectral equipment can be located uphole or downhole.

Abstract: The present disclosure relates to an integrated nuclear magnetic resonance (NMR) transceiver array, the array including a plurality of integrated NMR transceiver circuits disposed on a single chip. At least one of the plurality of integrated NMR transceiver circuits includes a transmitter that receives and outputs a radio frequency (RF) pulse train and a receiver that receives an NMR signal.

Abstract: A method and system for applying nuclear quadrupole resonance (NQR) sequences to a substance and determining presence of a chemical species within the substance using the sequences are described herein. The method includes applying an NQR pulse sequence to the substance using a non-resonant transmitter circuit. The method further includes detecting a NQR signal within the substance and determining presence of a chemical species within the substance using the NQR signal.

Abstract: A transmitter for a magnetic resonance (MR) system, such as nuclear magnetic resonance (NMR) system, is described herein. The transmitter includes a coil for applying NMR pulse sequences to a substance. The coil includes a first coil section and a second coil section. The first coil section and second coil section pass current in opposite polarity. The transmitter may also include a transmitter circuit for generating the NMR pulse sequences and providing the NMR pulse sequences to the coil. The transmitter circuit includes a first switch that selectively powers the first coil section and a second switch that selectively powers the second coil section. Operation of the first switch and the second switch generates the NMR pulse sequences.

Abstract: A method and system for determining a geometry of a borehole includes forming an nuclear magnetic resonance (NMR) caliper with a plurality of coils and coupling the NMR caliper to a borehole assembly. The NMR caliper may be calibrated for porosity and the T2 of the drilling mud, prior to drilling, at the surface. After drilling commences, scans of the borehole may be conducted with each coil of the NMR caliper. Each scan may include propagating RF energy across a range of frequencies with each coil in order to excite a NMR signal at varying depths. Borehole wall distances from the NMR caliper may be determined by reviewing a plurality of T2 distributions from CPMG measurements derived from the scans. In some embodiments, borehole wall distances from the NMR caliper may be determined by reviewing porosity values derived from the scans.

Abstract: Methods for analyzing a formation samples using nuclear magnetic resonance (NMR) are described herein. One method includes performing an NMR measurement of the formation sample to obtain NMR data. The NMR measurement detects NMR signals with echo times of less than or equal to 100 microseconds. The NMR data is analyzed to determine a measure of organic hydrogen content of the formation sample, such as (i) total organic hydrogen content, (ii) kerogen content, (iii) bitumen content, and/or (iv) oil content.