Abstract: A nuclear magnetic resonance (NMR) system that uses a feedback induction coil to detect NMR signals generated within a substance is described herein. In one embodiment, the NMR system uses the Earth's magnetic field in conjunction with a transmitter coil that applies NMR sequences to a formation. The NMR sequences generate a weak NMR signal within the formation due to the weakness of the Earth's magnetic field. This weak NMR signal is detected using the feedback induction coil.

Abstract: This application is related to a system and methods for sampling fluids and gases using nuclear magnetic resonance (NMR) technology. Specifically the system is related to an improved metallic pipe design for use at oil and gas well heads that includes integral coils for transmitting an NMR pulse sequence and detecting NMR signals and can be used as a component of an NMR instrument. The methods are related to obtaining and analyzing NMR spectra in stationary and flowing states.

Abstract: Provide are compositions and methods for electromagnetic (EM) surveying of subsurface hydrocarbon reservoirs using a giant dielectric material as a contrast agent. An injection fluid composition for EM surveying may include an aqueous fluid and giant dielectric nanoparticles having a dielectric constant of at least 10000 in the 1 Hz to 1 MHz frequency range. EM surveying of a subsurface hydrocarbon reservoirs may be performed by introducing an injection fluid having the giant dielectric nanoparticles into the subsurface hydrocarbon reservoir and generating an image of the position of the injection fluid from a transit time of emitted EM energy that traveled through the reservoir.

Abstract: A method of estimating fluid saturations includes obtaining amplitude values of nuclear magnetic resonance (NMR) data for a material, with each amplitude value being associated with a longitudinal magnetization recovery (T1 relaxation) time and a transverse magnetization decay (T2 relaxation) time. A mean is calculated as a function of the amplitude values and the T1 and T2 relaxation times for the amplitude values. Hydrocarbon saturation of pore space of the material is estimated as a function of the deviation of the mean from a threshold hydrocarbon saturation indicator and a threshold water saturation indicator, using the processor. Water saturation of the pore space of the material is estimated as a function of the deviation of the mean from the threshold hydrocarbon saturation indicator and the threshold water saturation indicator, using the processor.

Abstract: A method of using NMR to estimate pore connectivity in a shale formation by estimating organic pore connectivity in a first sample of the shale formation and inorganic pore connectivity in a second sample of the shale formation based on uptake of brine and hydrocarbon phases. Porosity partitioning of the shale formation may be estimated with a third sample of the shale formation.

Abstract: During operation, a system may apply a polarizing field and an excitation sequence to a sample. Then, the system may measure a signal associated with the sample for a time duration that is less than a magnitude of a relaxation time associated with the sample. Next, the system may calculate the relaxation time based on a difference between the measured signal and a predicted signal of the sample, where the predicted signal is based on a forward model, the polarizing field and the excitation sequence. After modifying at least one of the polarizing field and the excitation sequence, the aforementioned operations may be repeated until a magnitude of the difference is less than a convergence criterion. Note that the calculations may be performed concurrently with the measurements and may not involve performing a Fourier transform on the measured signal.

Abstract: A petrophysically regularized time domain nuclear magnetic resonance (NMR) inversion includes using an NMR tool to acquire NMR data and inverting the acquired NMR data in a time domain using petrophysical constraints. The inverted NMR data is analyzed. The petrophysical constraints may be identified by: determining a number of porobodons to seek, defining a plurality of zones in which only a subset of porobodon sets is present, and stacking all NMR echoes in each zone satisfying discriminators. The number of porobodons to seek may be based on knowledge of core samples, logs, and NMR sensitivity. The discriminator logs may be logs sensitive to porosity partitioning. A computing system having a processor, a memory, and a program stored in memory may be configured to perform the method. The system may be conveyed downhole on a wireline, a while-drilling drill string, a coiled tubing, a slickline, or a wired drill pipe.

Abstract: In some embodiments, an apparatus and a system, as well as a method and article of manufacture, may operate to measure nuclear magnetic resonance relaxation times in a fluid. Further activity may include determining a viscosity of the fluid based on at least one ratio of the relaxation times, and operating a controlled device based on the viscosity. Additional apparatus, systems, and methods are disclosed.

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: Methods estimating a property of a porous media include: saturating a sample of the porous media; spinning the sample in a centrifuge with a first end of the sample closer to an axis of rotation of the centrifuge than a second end of the sample; obtaining a first estimate of the first property; saturating the sample of the porous media; spinning the sample in a centrifuge with the second end of the sample closer to the axis of rotation of the centrifuge than the first end of the sample; obtaining a second estimate of the first property; and determining the second property of the porous media based at least in part on the first estimate of the first property and the second estimate of the first property. The first property can be a T2 distribution and the second property can be a T2 cutoff.

Abstract: A method for determining earth formation properties including a data acquisition tool and a data acquisition processor coupled with NMR sensors and a first memory; transmitting earth formation fluid data to a data processing unit comprising a processor and a second memory. Obtaining a fully polarized state echo train (EFR) and a partially polarized state echo train burst (EPR); inverting the EPR to obtain an apparent transverse relaxation time (T2app) distribution; truncating the T2app distribution by discarding the partially polarized state echo train data; completing a forward model of the EPR to obtain an additional echo train burst (EFR_B), performing a second inversion of the data set; and determining earth formation fluid properties.

Abstract: A mineralogy composition of a formation of interest is determined using core samples or downhole measurements. A dry permittivity is determined for each identified mineral. A volumetric mixing law is employed using the determined mineralogy composition and the determined dry permitivities. An effective matrix permittivity is determined using results from the volumetric mixing law. Dielectric dispersion measurements of the subject formation are acquired using the core samples or the downhole measurements. A dielectric petrophysical model is produced using the dielectric dispersion measurements and the effective matrix permittivity. A water saturation is estimated based on the dielectric petrophysical model. Nuclear magnetic resonance (NMR) T2 measurements having short echo spacings are acquired. A NMR petrophysical model is generated based on the NMR T2 measurements. A total porosity is determined based on the generated NMR petrophysical model.

Abstract: Core samples may been collected in a subterranean formation, preserved downhole in a pressurized nuclear magnetic resonance (NMR) core holder (1) comprising components for NMR imaging and (2) capable of maintaining the core samples at downhole fluid saturation state. For example, a pressurized NMR core holder may comprise a housing capable of containing downhole fluid pressures; a coil holder lining an inside of the housing and defining a core chamber; and one or more NMR coils maintained in a longitudinal position along the housing by the coil holder. Further, a system for performing the NMR imaging may comprise: a holder that maintains a pressurized NMR core holder in a desired position; and one or more magnets that are longitudinally movable along the pressurized NMR core holder.

Abstract: A MRI quality assurance device, according to the present invention, has a housing made of a rigid MRI invisible material containing one or more sealed reservoirs containing a fluid MRI signal producing material. Each sealed reservoir has a first volume portion and a second variable volume portion in fluid communication therewith.

Abstract: A nuclear magnetic resonance coil configuration having at least one flat or cylindrical coil (18), through which current flows in operation, which coil generates a high-frequency magnetic B1 field at the location of a sample (16) which is oriented parallel to an x-axis, and which for the purpose of connection to a tuning network is connected to at least two electrical feed lines (11), through which in-phase currents flow in operation, and which generate a high-frequency magnetic B2 field in the sample (16), the orientation of which encloses an angle ? with the direction of the B1 field, is characterized in that the following applies for the angle ?: ?=180°±??, where ??<90°. In this way, a B1 field profile, which is as rectangular as possible and is particularly steep on both sides, can be generated.

Abstract: A method for correcting motion-effects from a downhole measurement includes, in one embodiment, determining relative motion of a downhole logging tool for a given logging operation in a borehole formed in an earth formation, determining a motion induced signal decay (MID) based upon the determined relative motion, determining a motion-effect inversion kernel (MEK) based upon the determined MID, using the downhole logging tool to acquire measurements that are affected by motion of the downhole logging tool during the logging operation, and using the MEK to process the acquired motion-affected measurements to obtain motion-corrected data. Corresponding systems, devices, and apparatuses are also disclosed herein.

Abstract: Technologies applicable to NMR spin-echo amplitude estimation are disclosed. Example methods may calibrate for distortion of a shape and estimated amplitude of measured NMR spin or gradient echoes. NMR spin or gradient echo measurements may be performed on a sample. The measured NMR spin or gradient echoes may be used to calculate an echo-shape calibration factor. The echo-shape calibration factor may estimate an effect of echo shape on estimated spin or gradient echo amplitude(s) of the NMR spin or gradient echoes. The echo-shape calibration factor may be used to correct for underestimation or overestimation of the spin or gradient echo amplitude(s).

Abstract: An apparatus for estimating properties of an earth formation includes a nuclear magnetic resonance (NMR) measurement device including a magnet assembly, at least one transmitting assembly configured to generate an oscillating magnetic field in the formation, and a receiver configured to detect NMR signals from at least a sensitive volume in the formation. The apparatus also includes a processing device configured to receive NMR data corresponding to the detected NMR signals. The processing device is configured to perform combining a geometrical factor of the NMR logging tool with a temperature distribution, the temperature distribution indicating a temperature value at at least one location in the sensitive volume of the formation, correcting the NMR data based on the temperature value, estimating a property of the formation based on the corrected NMR data, and performing one or more aspects of an energy industry operation based on the estimated property.

Abstract: An embodiment of a nuclear magnetic resonance (NMR) apparatus for estimating properties of an earth formation includes an NMR measurement device including a transmitting assembly configured to emit a pulse sequence and a receiving assembly configured to detect an echo train based on the pulse sequence, and a processor. The processor is configured to perform receiving input parameters including an axial speed of the NMR measurement device and a T1 value associated with a selected formation fluid, analyzing polarization data associated with the T1 value, the polarization data describing a dependency between polarization and axial speed, determining a wait time for the pulse sequence based on the polarization data, applying the pulse sequence with the determined wait time to the transmitting assembly, and estimating a property of the earth formation based on the echo train detected by the receiving assembly in response to the pulse sequence.

Abstract: A disclosed nuclear magnetic resonance (NMR) logging tool includes a static magnetic field source. The NMR logging tool also includes a pulsed magnetic field source with an operational range corresponding to a predetermined frequency range and a predetermined amplitude range. The NMR logging tool also includes a controller in communication with the pulsed magnetic field source. The controller performs a calibration for the pulsed magnetic field source to optimize an NMR parameter. The calibration uses a reduced search space within the operational range to select a frequency and an amplitude that optimize the NMR parameter.

Abstract: For a given medium, a property may be inferred based on nuclear magnetic resonance (NMR) data. NMR data that includes two or more different NMR signals are used. Differences between any particular two of the two or more different NMR decays are computed and a distribution is produced based on the computed differences. The property of the medium may be inferred using the produced distribution. The produced distribution features the change in a parameter. The NMR distributions may be T2 distributions, T1 distributions, diffusion, or any other type of NMR data. The NMR data may be acquired: at different times, for different levels of invasion, before and after water flooding, or for different saturation states. The inferred property may pertain to the oil and gas industry, material analysis, medicine, pharmaceuticals, the process industry, or the food industry. For example, the inferred property may be the porosity of a subsurface formation.

Abstract: An NMR sensor and method is disclosed for analyzing a core sample from a subsurface formation. Embodiments of the method utilize two or more magnets disposed proximate to each other. The configuration of the magnets allows for increased detection frequency, and creates a strong field with much finer resolution than existing designs. In addition, embodiments of the sensor may be used at the well site due to its small size and simple hardware. Further details and advantages of various embodiments of the method are described in more detail herein.

Abstract: Methods and systems for characterizing a subterranean formation using nuclear magnetic resonance (NMR) measurements are described herein. One method includes locating a downhole logging tool in a wellbore that traverses the subterranean formation, and performing NMR measurements to obtain NMR data for a region of the subterranean formation. The NMR data is processed by employing sparse Bayesian learning (SBL) to determine a multi-dimensional property distribution of the NMR data (e.g., T1-T2, D-T2, and D-T1-T2 distributions). The sparse Bayesian learning can utilize Bayesian inference that involves a prior over a vector of basis coefficients governed by a set of hyperparameters, one associated with each basis coefficient, whose most probable values are iteratively estimated from the NMR data. The sparse Bayesian learning can achieve sparsity because posterior distributions of many of such basis coefficients are sharply peaked around zero.

Abstract: A well-logging method for a geological formation having a borehole therein may include collecting a plurality of nuclear magnetic resonance (NMR) snapshots from the borehole indicative of changes in the geological formation and defining NMR data. The method may further include identifying a plurality of fluids within the geological formation based upon the NMR data, determining respective NMR signatures for the identified fluids based upon the NMR data, determining apparent volumes for the identified fluids based upon the NMR signatures, and determining adjusted volumes for the identified fluids based upon the apparent volumes.

Abstract: In some aspects, a downhole nuclear magnetic resonance (NMR) tool includes a magnet assembly and an antenna assembly. The NMR tool can operate in a wellbore in a subterranean region to obtain NMR data from the subterranean region. The magnet assembly produces a magnetic field in a volume about the wellbore. The magnet assembly includes a central magnet, a first end piece magnet spaced apart from a first axial end of the central magnet, and a second end piece magnet spaced apart from a second axial end of the central magnet. The antenna assembly includes a transversal-dipole antenna. In some cases, orthogonal transversal-dipole antennas produce circular-polarized excitation in the volume about the wellbore, and acquire a response from the volume by quadrature coil detection.

Abstract: A method for estimating an effect on nuclear magnetic resonance (NMR) measurements of an invasion of solid particles into pores of an earth formation penetrated by a borehole includes conveying a carrier through the borehole and performing an NMR measurement on a volume of interest in the formation to provide a relaxation time constant using an NMR tool disposed at the carrier. The method further includes receiving information describing the solid particles in the pores and quantifying, using a processor, an effect on the measured relaxation time constant due to the invasion of solid particles using the received information.

Abstract: The present invention provides a three-dimensional nuclear magnetic resonance logging instrument probe, a logging instrument and an antenna excitation method, where the probe includes: a probe framework, a magnet and an antenna; four magnets are uniformly distributed along a circumference of the probe framework, the magnets are magnetized in a radial direction of the probe framework, two magnets placed opposite to each other are magnetized from outside to inside, and the other two magnets placed opposite to each other are magnetized from inside to outside; in the probe framework, each of the magnets is provided with independently fed antennas; antennas corresponding to each of the magnets comprise a left antenna provided on one side of the corresponding magnet and a right antenna provided on the other side of the corresponding magnet; the left antenna and the right antenna corresponding to each magnet are electrically connected.

Abstract: Provided in some embodiments are systems and methods for determining characteristics of a hydrocarbon reservoir. Embodiments include conducting a nuclear magnetic resonance (NMR) logging operation of a targeted reservoir section of a wellbore extending into a hydrocarbon reservoir to generate a NMR log of the targeted reservoir section, conducting a resistivity logging of the targeted reservoir section to generate an uninvaded water saturation (Sw) log of the targeted reservoir section, determining for each of a plurality of depths in the section, a T2 cutoff point based on values of the NMR and Sw logs, identifying a subset of the T2 cutoff points that exhibit a hyperbolic trend, determining a theoretical cutoff curve corresponding to the subset of the T2 cutoff points, determining a free water level (FWL) of the reservoir based on the theoretical cutoff curve, and determining a rock type of the reservoir based on the theoretical cutoff curve.

Abstract: A MRI quality assurance device, according to the present invention, has a housing made of a rigid MRI invisible material containing one or more sealed reservoirs containing a fluid MRI signal producing material. Each sealed reservoir has a first volume portion and a second variable volume portion in fluid communication therewith.

Abstract: An NMR/MRI-based integrated system for analyzing and treating of a drilling mud for drilling mud recycling line; the system comprising drilling mud recycling equipment; an NMR/MRI device configured to provide at least one image of at least a portion of the drilling mud at least one characterized recycling step in the drilling mud recycling line; and a processor for analyzing and controlling the recycling of the drilling mud; wherein the NMR/MRI-based integrated system is operating in a method of analyzing the NMR/MRI image online; operatively communicating results of the analysis to the drilling mud recycling equipment; and online feedback controlling at least one step in the recycling of the drilling mud recycling equipment, thereby controlling automatically at least one step in the recycling of the drilling mud recycling.

Abstract: A microfluidic device and method is described to parallelize a pressure-volume-temperature (“PVT”) analysis such that a portion of the pressure, temperature and volume analysis is performed separately from others. The resulting PVT data is then recombined statistically for a complete PVT analysis. The microfluidic device may also obtain compositional data of the fluid to perform an equation of state analysis or reservoir simulations.

Abstract: A flowmeter for determining the flow of a multi-phase medium through a measuring tube has a first and a second measuring device, one of which operates on a tomographic measuring principle and one of uses a measuring principle based on nuclear magnetic resonance. The first measuring device operates in a different manner from the second measuring device, e.g., using a measuring device operating on the measuring principle of pre-magnetization contrast measurement and having a pre-magnetization section with a constant magnetic field. The magnetic field has at least one component perpendicular to the direction of flow of the multi-phase medium and is generated by using magnetic field generating elements, which are arranged around the measuring tube. Additionally, an assembly for exciting nuclear spin by a RF excitation pulse or a RF excitation pulse sequence is part of the measuring device.

Abstract: A disclosed method for characterizing gas adsorption on a rock sample includes: measuring a nuclear magnetic resonance (NMR) response of the rock as a function of surrounding gas pressure along an isotherm; transforming the NMR response to obtain a Langmuir pressure distribution of gas adsorption on the rock sample; and displaying the Langmuir pressure distribution. The Langmuir pressure distribution may be shown in one dimension (e.g., contribution to signal response versus Langmuir pressure), or may be combined with additional pressure-dependencies such as spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and chemical shift (?) to form a multi-dimensional distribution. The method can further include: identifying peaks in the Langmuir pressure distribution; and associating a gas storage mechanism and capacity with each peak.

Abstract: A well-bore monitoring process involving logging the temperature of a soil, rock, and brine mixture present in a carbonate formation continuously, and simultaneously logging the resistivity of the soil, rock, and brine mixture in the carbonate formation continuously. The logged temperature and the logged resistivity are interpreted whereby concurrent events in the logged temperature and the logged resistivity identify dissolution of rock into the mixture and precipitation of scale from the mixture. The simultaneous logging of the temperature and the resistivity is conducted in a well-bore in the carbonate rock formation.

Abstract: A magnetic flowmeter has a transmitter module that generates a drive signal for driving a magnetic field in a flowing fluid. A flowtube module samples a voltage induced in the fluid by the magnetic field and generates a measurement signal. A single communication path carries the drive signal from the transmitter module to the flowtube module and the measurement signal from the flowtube module to the transmitter module. The flowtube module generates a digital measurement signal. The flowtube module can include a processor for bundling the measurement signal with other information such as calibration data for the flowtube. In addition, the processor can control the timing of flowtube module operations so that the flowtube module samples the induced voltage and transmits the measurement signal to the transmitter module at different times.

Abstract: A nuclear magnetic resonance (NMR) apparatus includes a transmitting assembly configured to emit one or more dual-wait-time pulse sequences, and a receiving assembly configured to detect a long-wait-time echo train and a short-wait-time echo train. The apparatus also includes a processor configured to perform at least one of: estimating a difference between the long-wait-time echo train and the short-wait-time echo train to generate a differential echo-train, inverting the differential echo-train into a differential T2 distribution, and detecting a motion artefact in response to determining that the differential echo-train includes a short-T2 porosity fraction that is greater than a threshold value; and inverting two echo trains into two T2 distributions, calculating at least two porosity fractions for each of the two T2 distributions, estimating a shift of a porosity amount between the at least two porosity fractions, and detecting the motion artefact based on the shift.

Abstract: A new method of assessing wettability of a reservoir rock is provided, using a mineral oil/alkane saturated sample first, a crude oil and water saturated sample equivalent to natural reservoir rock second, and a third crude oil saturated, water free sample, measuring different wettability states and comparing the slopes of all three adjusted values to determine a wettability state for the reservoir rock.

Abstract: A nuclear magnetic resonance (NMR) logging method includes providing a hybrid pulse sequence having a saturation pulse, an inversion pulse, and a detection sequence. The method also includes measuring echo signals in response to the hybrid pulse sequence. The method also includes deriving a spin-lattice time constant (T1) distribution from the measured echo signals. A NMR system includes a hybrid pulse sequence module to provide a hybrid pulse sequence with a saturation pulse, an inversion pulse, and a detection sequence. The NMR system also includes a control module to select a time interval between the saturation pulse and the inversion pulse.

Abstract: A nuclear magnetic resonance (NMR) apparatus includes at least one solenoid configured to induce a radio frequency magnetic field in a sample. The sample is located inside the solenoid. At least one cylindrical magnet is arranged to induce a static magnetic field in the sample, wherein the magnet is located inside the sample.

Abstract: NMR properties of earth formations are determined using a logging device movable in a borehole. The logging device includes a magnet assembly to generate a static magnetic field and an antenna expandable from the surface of the magnet assembly into the borehole toward the borehole wall to increase the magnetic dipole moment of the antenna. The logging device can be lowered or raised through a drill pipe with the magnet assembly being configured to generate no magnetic field while the device is conveyed within the drill pipe. The logging device may also include a side-looking sensor to acquire fast relaxation component of the NMR signals.

Abstract: Nuclear magnetic resonance apparatuses and methods for estimating properties of an earth formation are provided. An apparatus includes a carrier configured to be deployed in a borehole, at least one transmitting assembly configured to generate an oscillating magnetic field in a volume of interest within the earth formation, at least one receiving assembly configured to detect a nuclear magnetic resonance (NMR) signal originating in the volume of interest; and a magnet assembly configured to generate a static magnetic field in the formation from a primary side of the magnet assembly. The magnet assembly includes an array of longitudinally elongated magnets having a rotating pattern of magnetic orientations, the array configured to generate the static magnetic field in the volume of interest, and the static magnetic field strength is higher at the primary side than the field strength at a side of the magnet assembly that is opposite the primary side.

Abstract: A computing system comprises one or more core processors coupled to a communication network among the cores via a switch in each core and switching circuitry to forward data among cores and switches. Features include a programmable classification processor for directing packets, techniques for managing virtual functions on an IO accelerator card, packet scheduling techniques, multi-processor communication using shared FIFOs, programmable duty cycle adjustment and delay adjustment circuits, a new class of instructions that use a ready bit, and cache coherence and memory ordering techniques.

Abstract: Systems, methods, and software for modeling subterranean formation viscosity are described. In some aspects, a method of training a subterranean fluid viscosity model based on NMR data includes accessing multiple relaxation-time distributions generated from NMR measurements of a fluid, normalizing each relaxation-time distribution to a common normalizing value, computing parameters for a plurality of weighted radial basis functions from the normalized relaxation-time distributions, and producing a subterranean fluid viscosity model that includes the weighted radial basis functions and the computed parameters.

Abstract: The present invention provides a transmitter for an electromagnetic survey system for transmitting signals having a waveform comprising at least a first pulse and a second pulse, wherein the first and second pulses are different in at least one of shape and power. Embodiments of the invention enable combining various distinct pulses that may have been optimized for respective applications to form a transmitter waveform for conducting a geological survey. In effect, the embodiments of the present invention provides an EM system that is substantially equivalent to multiple EM systems operating at the same time for collecting data in relation to different aspects of the geology of interest. Advantageously, the benefits of the present invention can be obtained without the undesirable complexity and cost associated with the simultaneous deployment of multiple EM systems.

Abstract: A nuclear magnetic resonance (NMR) sample analyzer has a plurality of NMR units arrayed in a predetermined relationship to each other. Each of the NMR units includes a sample chamber having a sensitive volume for containing a sample to be analyzed; a radio frequency (RF) transmitting and receiving device proximal the sample chamber; and a magnet surrounding the RF transmitting and receiving device and sample chamber for generating a substantially uniform magnetic field within the sensitive volume and substantially no magnetic field beyond an outside wall of the magnet.

Abstract: In a method to optimize a magnetic resonance sequence of a magnetic resonance apparatus and a magnetic resonance apparatus operated according to such a method, optimization of the timing of the magnetic resonance sequence is implemented by adopting a magnetic resonance sequence as a starting sequence includes a first time interval set of one or more first time intervals and a second time interval set of one or more second time intervals, wherein the first time intervals of the first time interval set are to be left unmodified with regard to an optimization of the duration. The magnetic resonance sequence is automatically analyzed to identify the first time intervals of the first time interval set and the second time intervals of the second time interval set in the magnetic resonance sequence. The duration of at least one second time interval of the second time interval set is then automatically optimized.

Abstract: Porosity of a subterranean region is estimated by accessing a nuclear magnetic resonance (NMR) relaxation distribution corresponding to NMR measurements of a subterranean region in which the NMR relaxation distribution includes multiple of peaks, fitting Gaussian functions to the NMR relaxation distribution to establish values for fitting parameters for each of the Gaussian functions, determining the porosity of the subterranean region based on the values of the fitting parameters of the Gaussian functions, and categorizing the porosity based on a relationship between the fitting parameters of the Gaussian functions and a distribution of pore sizes.

Abstract: A methods are provided for investigating a sample containing hydrocarbons by subjecting the sample to a nuclear magnetic resonance (NMR) sequence using NMR equipment, using the NMR equipment to detect signals from the sample in response to the NMR sequence, analyzing the signals to extract a distribution of relaxation times (or diffusions), and computing a value for a parameter of the sample as a function of at least one of the relaxation times (or diffusions), wherein the computing utilizes a correction factor that modifies the value for the parameter as a function of relaxation time for at least short relaxation times (or as a function of diffusion for at least large diffusion coefficients).

Abstract: Systems, tools, and methods for measurement of a property of a solid body or fluid involve an electromagnetic measurement tool that includes a transmitter configured to transmit electromagnetic energy, a receiver configured to receive the electromagnetic energy, and a metamaterial element comprising a negative refractive index. The metamaterial element may focus the electromagnetic energy. The electromagnetic tool may be placed adjacent the solid body or fluid, electromagnetic energy may be transmitted via the transmitter, and the electromagnetic energy may be received with the receiver to measure a property of the solid body or fluid.

Abstract: Techniques for calculating metrics for reservoir quality based on light oil and total organic carbon in tight oil reservoirs are described. The techniques include calculating quantities of light oil and total organic carbon from logging data and generating therefrom a continuous log for reservoir quality metric. Additionally new reservoir quality indices are presented that more accurately predict reservoir quality in tight oil plays.