Abstract: A method of identifying a material and/or condition of a material in a borehole is described, together with related apparatus. The material may either be between first and second tubulars or between a first tubular and a wall of the borehole. The method may include providing a reference quality factor (Qreference) for one or more known materials in one or more known conditions and measuring a downhole quality factor (Qmeasured) of the material and/or material condition to be identified. A spectral ratio ?=(Qmeasured/Qreference) may then be computed for one or more known materials under one or more known conditions followed by an analysis of the spectral ratios to identify the material and/or condition of the material in the borehole.

Abstract: A method and system are described for imaging core samples associated with a subsurface region. The imaging results may be used to create or update a subsurface model and using the subsurface model and/or imaging results in hydrocarbon operations. The imaging techniques may include NMR imaging and CT imaging. Further, the imaging techniques may also include exposing the core sample to the imaging gas.

Abstract: There is described a method for determining the relative quantities of the expected components in a multi-component mixture of solids. The proposed quantification method makes use of a time domain nuclear magnetic resonance (TD-NMR) spectrometer and requires that, for each of the expected components in the mixture, a T1 saturation recovery curve (SRCi) is measured and recorded. The saturation recovery curve for the mixture sample (SRCmix) is determined from a measurement of the sample with the spectrometer. The relative amounts of the expected components present in the mixture sample are determined by fitting a linear combination of the component SRCs (SRCi) to the SRCmix. The resulting value of each weighting coefficient in the fit provides the relative proportion of the corresponding component in the overall sample.

Abstract: In one embodiment, an MRI apparatus includes: an MRI scanner configured to acquire N+1 or more diffusion-weighted images by differently setting parameter values among the diffusion-weighted images, with regard to N types of parameters, wherein N is a natural number equal to or more than two; and processing circuitry configured to generate a computed diffusion-weighted image having an arbitrary value for at least one of the N types of parameters, based on relationship between signal values of the acquired diffusion-weighted images and the parameter values differently set among the acquired diffusion-weighted images.

Abstract: The instant invention relates to a method for noise reduction from a magnetic resonance sounding (MRS) oscillating signal, and more particularly, to a data processing method for reducing random noise contained in MRS oscillating signal based on joint algorithm principles of EMD and TFPF. A MRS oscillating signal is decomposed into different eigen-mode components by using decomposition characteristic of EMD algorithm; then a signal-dominated eigen-mode component is encoded as an instantaneous frequency of an analytical signal of unit amplitude using TFPF algorithm; and random noise is suppressed with the characteristics that the time-frequency distribution of the analytical signal is concentrated along with the instantaneous frequency. The method requires fewer filtering constraints and is simple to operate without need of designing a filtering interval in the time-frequency domain, and has good adaptability to the MRS oscillating signal with a low signal-noise-ratio.

Abstract: Nuclear magnetic resonance (NMR) tools, logging systems, and methods for measuring NMR properties of earth formations in a region of interest are provided. The NMR tool includes an antenna assembly, a magnet assembly, a compensating assembly, and a motion sensor. The antenna assembly is operable to generate a radio-frequency magnetic field and the magnet assembly is operable to generate a static magnetic field. The motion sensor is operable to generate readings for lateral motion of the antenna and magnet assemblies. The compensating assembly contains at least one electromagnet and is operable to reduce variation of the static magnetic field in the region of interest due to the lateral motion during NMR measurements based on the readings for the lateral motion.

Abstract: One methods for in-situ characterization of a reservoir rock includes: (a) sealing an interval corresponding to a selected depth or depths within the subterranean formation; (b) injecting a displacement fluid into the interval, wherein the displacement fluid displaces a reservoir fluid stored in the reservoir rock; (c) monitoring movement of the displacement fluid or the reservoir fluid in the reservoir rock; and (d) assessing wettability of the reservoir rock based on (c) or determining recovery rate of the reservoir fluid.

Abstract: A formation evaluation system reduces inversion matrixes used to determine formation properties, thereby increasing the memory management and processing efficiency of the evaluation system. NMR data is acquired from a wellbore and expressed mathematically by the system as a least squares solution to a linear system. The least squares solution is approximated using a numerical decomposition method and the evaluation system determines a formation property using the approximated least squares solution. Thereafter, a downhole operation may be planned, analyzed or conducted using the determined formation property.

Abstract: This disclosure describes systems and methods to predict viscosity of heavy oil in a geological formation, even when the geological formation also contains water such as clay-bound water, using a downhole nuclear magnetic resonance (NMR) tool. The downhole NMR tools may obtain responses include distributions of a first relaxation time T1, a second relaxation time T2, or diffusion, or a combination of these. The responses of the NMR measurements that are due to water are separated from the responses of the NMR measurements that are due to heavy oil. The responses of the NMR measurements due to heavy oil are then related to likely values of viscosity of the heavy oil based on empirical or simulated measurements.

Abstract: Described herein are apparatuses for analyzing an optical signal decay. In some embodiments, an apparatus includes: a source of a beam of pulsed optical energy; a sample holder configured to expose a sample to the beam; a detector comprising a number of spectral detection channels configured to convert the optical signals into respective electrical signals; and a signal processing module configured to perform a method. In some embodiments, the method includes: receiving the electrical signals from the detector; mathematically combining individual decay curves in the electrical signals into a decay supercurve, the supercurve comprising a number of components, each component having a time constant and a relative contribution to the supercurve; and numerically fitting a model to the supercurve.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for performing electron paramagnetic resonance (EPR) spectroscopy on a fluid from a flowing well, such as fluid from hydrocarbon recovery operations flowing in a downhole tubular, wellhead, or pipeline. One example method generally includes, for a first EPR iteration, performing a first frequency sweep of discrete electromagnetic frequencies on a cavity containing the fluid; determining first parameter values of reflected signals from the first frequency sweep; selecting a first discrete frequency corresponding to one of the first parameter values that is less than a threshold value; activating a first electromagnetic field in the fluid at the first discrete frequency; and while the first electromagnetic field is activated, performing a first DC magnetic field sweep to generate a first EPR spectrum.

Abstract: Methods and related systems are described for estimating fluid or rock properties from NMR measurements. A modified pulse sequence is provided that can directly provide moments of relaxation-time or diffusion distributions. This pulse sequence can be adapted to the desired moment of relaxation-time or diffusion coefficient. The data from this pulse sequence provides direct estimates of fluid properties such as average chain length and viscosity of a hydrocarbon. In comparison to the uniformly-spaced pulse sequence, these pulse sequences are faster and have a lower error bar in computing the fluid properties.

Abstract: Nuclear magnetic resonance (NMR) well logs are obtained from a well in the reservoir measures of the total fluid, including both water and hydrocarbon, in the shale of the reservoir. NMR measurement at the surface of shale subsurface samples obtained in from drill cuttings or core samples of the same well provide measures of total water content of the shale. At the surface, pressure on the subsurface sample becomes that of atmospheric pressure, and hydrocarbon gas contained in the shale cuttings bleeds off. The remaining fluid within the shale cuttings is then only water, which can be measured using NMR techniques. Compensation for the effect of drilling fluids (drilling mud) on the NMR measures from the fluid cuttings is also performed. The hydrocarbon gas content of the formation shale can be determined from the difference between formation NMR well log readings and NMR measurements from subsurface sample.

Abstract: A multiple curve capillary pressure data set derived from a core sample is discriminated into groups of similar curves representing similar pore structure groups. Primary reservoir development controlling factors (RDCFs) are identified for each pore structure group and a set of capillary pressure type curves are created for each pore structure group to statistically characterize saturation-pressure response. Data is processed from a core sample log to derive identified RDCFs from the log data. A preliminary reservoir development designation log is derived by applying cutoffs to the log-based RDCFs and a preliminary saturation distribution equivalent to the preliminary reservoir development designation log is obtained by applying the capillary pressure type curves. A capillary pressure type uncertainty envelope is compared with saturation measurements from the log. The modelled saturation from the average capillary pressure type curve is recalculated to generate an optimized reservoir development designation.

Abstract: A method of estimating a property of a porous media including: saturating a sample of the porous media with a fluid; spinning the sample in a centrifuge; obtaining a saturation profile of the sample; identifying a portion of the sample in which saturation of the sample is within 10% of a minimum saturation of the sample; and measuring a first property of the porous media on the identified portion of the sample.

Abstract: A system for measuring a property of fluid in an earth formation includes a downhole tool disposed in a borehole and configured to be movable within the borehole and a nuclear magnetic resonance (NMR) measurement device including a transmitter configured to emit at least two pulse trains of magnetic energy into the earth formation and a detector configured to detect a long-TW echo train and a short-TW echo train resulting from the at least two pulse trains. The system also includes a processor configured to combine the information from the at least two pulse trains and a rate of penetration of the downhole tool to form a measurement of the property.

Abstract: The present invention relates to a method for determining a non-oil volume of a rock sample comprising: receiving a rock sample; and receiving a non-oil zone in a NMR map using a T1T2 sequence, the non-oil zone being associated to non-oil in the map; Then, determining a first NMR map of the received rock sample using a T1T2 sequence, and determining a volume of non-oil in the received rock sample based on an integral in an integration zone of the firstNMR map. The integration zone of the first NMR map being determined based on the received non-oil zone, and a calibration value.

Abstract: A nuclear magnetic resonance device for subterranean characterization includes a tool body, a peripheral measurement device, and a controller. The tool body includes a permanent magnet located therein, permanent magnet inducing a static magnetic field (B0) in a region of interest. The peripheral measurement device is coupled to the tool body. The measurement device includes a radio frequency coil controllable to generate a radio frequency magnetic field (B1) in the region of interest, receive a response signal, or both. The controller is communicatively coupled to the radio frequency coil and controllable to drive the radio frequency coil, process the response signal, or both.

Abstract: Methods for quickly estimating apparent diffusion coefficient probability density functions (ADC PDFs) for each image voxel are provided using a “diffusion reproducibility evaluation and measurement” (DREAM) magnetic resonance sequence. Non-diffusion-weighted (reference) images collected simultaneously have blood oxygenation level dependent (BOLD) sensitivity that can be used for resting-state fMRI data to measure functional connectivity, an unbiased parameter reflecting neurological integrity. ADC coefficient of variation (ADC CV) measurements can be used to isolate and label regions of non-enhancing tumor and predict future enhancement independent of FLAIR, T2, or average ADC maps. Functional diffusion mapping (fDMs) using voxel-wise changes in ADC PDFs can be used to spatially visualize and statistically quantify response to treatment.

Abstract: An apparatus, method and non-transitory computer readable medium method are described for identifying the phase fractions and flow-rate of a petroleum carrying pipeline with three-phase wavy-stratified flow. A set of semi-cylindrical electrodes are mounted on the internal surface of a pipe to monitor the total capacitance and resistance of the three-phase contents. The phase fractions are determined by relating the resistance and capacitance to the phase-angles associated with the interfaces between water, oil and gas phases of the mixture. To calculate the flow rate, measured capacitances from two sets of electrodes with known separation distance are cross-correlated to determine time delay. Communications circuitry transmits the measurements to a remote control center for monitoring. Calculated and measured results demonstrate close agreement. The percentage error exhibited by the proposed inclined capacitive plate technique is calculated and compared with published values.

Abstract: A nuclear magnetic resonance (NMR) system and method for determining oil and water composition in drilling mud by separating out signals from oil and water in a two dimensional relaxation space wherein the oil and water ratio is a function of the separated out signals. The spin-lattice relaxation time distribution or a spin-spin relaxation time distribution of the sample is measured and a spin-lattice versus spin-spin or a spin-spin versus diffusion two-dimensional procedure is applied to separate the components of the drilling fluid. The signal intensities from the oil and water regions of the one-dimensional or two-dimensional NMR measurements are used to quantify the relative portion of the proton NMR signal from the oil and water and to determine the ratio of oil and water in the drilling mud.

Abstract: Various systems and methods for detecting electron spins using electron paramagnetic resonance are described. An excitation signal generator configured to generate an excitation signal of varying amplitude and phase as compared to a reference signal may be present. A crossed-loop resonator configured to isolate a detection signal produced by the excitation signal exciting an object with a magnetic field may also be present. Further, a detection device configured to detect electron spins of the object using the detection signal isolated by the crossed-loop resonator may be present.

Abstract: Various embodiments include a fiber optic nuclear magnetic resonance (NMR) sensor tool device and systems. One such tool includes a permanent magnet that generates a static magnetic field. A transmit antenna in the tool can operate to transmit a time-varying signal that is orthogonal to the static magnetic field. A fiber optic sensor element includes a coating that phase modulates a light signal traveling in the fiber when the coating is exposed to a varying field (e.g., a received, reflected magnetic field corresponding to the transmitted time-varying signal). The coating may be one of a magnetostrictive coating or a piezoelectric coating. Additional apparatus, systems, and methods are disclosed.

Abstract: The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for determining a permeability of a rock sample. One method includes measuring a first set of Nuclear Magnetic Resonance (NMR) relaxation times for the rock sample saturated with regular water (H2O); injecting heavy water (D2O) into the rock sample; measuring a second set of NMR relaxation times for the rock sample after injecting D2O; calculating a pore connectivity factor based on the first set of NMR relaxation times and the second set of NMR relaxation times; and calculating the permeability of the rock sample based on the pore connectivity factor.

Abstract: Certain techniques for Nuclear Magnetic Resonance (NMR) whole core logging are described. NMR tests are performed on a standard sample using a NMR radio frequency (rf) coil having a length. A response map of the NMR rf coil is determined. The response map relates multiple relative NMR rf coil positions to multiple relative signal intensities. The NMR tests are performed using the NMR rf coil on a rock sample containing fluid. A length of the rock sample is greater than the NMR rf coil. Fluid content in the sample is determined using results of the NMR tests using the NMR rf coil on the rock sample and using the response map for the NMR rf coil and a mathematical deconvolution to obtain high resolution. The same method can be used to obtain high spatial resolution NMR log measurement in the reservoir.

Abstract: An imager and method for imaging fluid of a subsurface formation is disclosed. The imager includes a housing having a sidewall defining a passage to receive a core sample of the subsurface formation therethrough. The housing is positioned in a downhole tool and has a fluid inlet to receive fluid from the subsurface formation into the passage. The imager also includes a permanent magnet positioned in the sidewall of the housing, a radio frequency coil positioned in the sidewall of the housing between the permanent magnet and the passage, a gradient field in the sidewall of the housing between the permanent magnet and the radio frequency coil, and a chemically-selective imager. The chemically-selective imager is operatively connected to the radio frequency coil to selectively pulse frequencies according to a pulse sequence whereby individual fluid measurements of the sample are generated.

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: Various embodiments include a method for generating a pulse for use in nuclear magnetic resonance (NMR) logging. One such method generates the pulse by adjusting one or more of pulse parameters including a pulse shape, a pulse amplitude, a pulse phase, and/or a pulse frequency. The generated pulse produces a substantially uniform nuclear spin saturation or nuclear spin inversion response from a fluid. A wait time between the pulse transmission and an echo that indicates spin equilibrium has been achieved is substantially equal to a T1 time indicating characteristics of the fluid.

Abstract: A method for estimating a property of a subsurface material includes: conveying a carrier through a borehole penetrating the subsurface material; performing at least two magnetic resonance (NMR) measurements in a volume of interest in the subsurface material using an NMR tool disposed on the carrier, wherein (i) a first NMR measurement has a first wait time and a first first-echo time and a second NMR measurement has a second wait time and a second first-echo time, (ii) the first wait time and the second wait time are less than or equal to 500 milliseconds, and (iii) the first first-echo time and the second first-echo time are different; receiving at least the first-echo of the first NMR measurement and receiving at least the first-echo of the second NMR measurement; and estimating the property of the subsurface material by using the at least two measured first-echoes simultaneously.

Abstract: A method for optimizing eddy current measurements includes conveying an electromagnetic tool through a borehole. The method further includes transmitting an excitation signal from the tool. The method further includes recording an eddy current response to the excitation signal from one or more tubings and casings within the borehole before the fall time of the excitation signal.

Abstract: The longitudinal relaxation times (T1) of water and hydrocarbon inside porous media, such as rock from subsurface formations, behave differently when external magnetic fields vary. A Nuclear Magnetic Relaxation Dispersion (NMRD) profile from Fast Field Cycling Nuclear Magnetic Resonance (FFC-NMR) technique differentiates the type of fluids filling the pores. Different types of pores in a rock sample are filled with different fluids, water and hydrocarbon, and the absolute porosity and the pore size of each type of pores is determined.

Abstract: A side-looking Nuclear Magnetic Resonance (“NMR”) logging tool is designed to reduce and/or eliminate a borehole signal. The logging tool includes a magnetic assembly and a radio frequency (“RF”) transceiver antenna. The axial extent of the RF transceiver antenna has a length selected to reduce a borehole signal.

Abstract: A tool having a pump-out unit, pumping unit, and NMR unit is disposed in a wellbore. On a pump-up cycle, after removing borehole fluids, a fluid is injected into a region of investigation. NMR measurements are made while fluid migrates into the region of investigation. On a production cycle, pressure is removed, allowing fluid to exit the formation while NMR measurements are made. A rate of fluid production is estimated using the time-dependent NMR measurements. Alternatively, the mass of a sample is measured. Fluid is injected into the sample and the mass of the injected sample is measured. Pressure is removed and the mass of the injected sample as the fluid migrates out of the sample is measured. The change in mass of the injected sample as the fluid migrates out of the sample is determined and a rate of fluid production is estimated using the determined change in mass.

Abstract: A method for processing nuclear magnetic resonance (NMR) measurement data includes receiving, with a processor, NMR measurement data obtained from an NMR tool, the NMR measurement data having an echo train affected by a motion artifact, wherein the motion artifact is related to a magnetic field magnitude that varies in a volume of interest due to a motion of the NMR tool. The method further includes reducing, with the processor, an effect on the NMR measurement data of the motion artifact by using a correcting inversion method that models the motion artifact to provide a corrected transverse relaxation time constant (T2) distribution, the correcting inversion method having a multiplicative term having a term that includes at least one local maximum and an optional decay term.

Abstract: Disclosed herein are methods for testing wettability of tight oil reservoir. The method comprises: by using a nuclear magnetic resonance testing method, testing nuclear magnetic resonance maps of the tight oil reservoir in the saturated water state and in the saturated oil state; by using the nuclear magnetic resonance maps, analyzing a water-wetting degree and an oil-wetting degree of the tight oil reservoir; calculating a mixed wettability index of the tight oil reservoir, and estimating the wettability of the tight oil reservoir according to the mixed wettability index. This disclosure can effectively improve testing efficiency, quantitatively analyze the water-wetting degree and the oil-wetting degree of the tight oil reservoir, and improve accuracy of testing results.

Abstract: Various embodiments include apparatus and methods to conduct measurements on a structure using a nuclear magnetic resonance tool. The nuclear magnetic resonance tool can be operated to make nuclear magnetic resonance measurements that generate transverse 5 relaxation time echo train sequences ending with a recovery pulse. Additional apparatus, systems, and methods are disclosed.

Abstract: NMR logging of hydrocarbon formations may be performed with a gradient multi-frequency NMR technique using an increased packing density of the sensitive volumes such that the radiofrequency (RF) pluses for adjacent sensitive volumes interfere. An exemplary method may include applying first and second sequences of RF pulses at first and second frequencies, respectively, the second sequence being applied at a time interval following the first sequence; acquiring the NMR relaxation data from first and second sensitive volumes corresponding to the first and second frequencies, respectively; and selecting the first and second frequencies and the time interval to allow for interference between the first sequence of RF pulses and the NMR relaxation data from the second sensitive volume in order to increase a signal-to-noise ratio and a signal-to-noise ratio per square root of time of the NMR relaxation data.

Abstract: Apparatus, methods, and other embodiments associated with NMR fingerprinting are described. One example NMR apparatus includes an NMR logic configured to repetitively and variably sample a (k, t, E) space associated with an object to acquire a set of NMR signals. Members of the set of NMR signals are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The varying parameters may include flip angle, echo time, RF amplitude, and other parameters. The NMR apparatus may also include a signal logic configured to produce an NMR signal evolution from the NMR signals, a matching logic configured to compare a signal evolution to a known, simulated or predicted signal evolution, and a characterization logic configured to characterize a resonant species in the object as a result of the signal evolution comparisons.

Abstract: A method for characterizing wettability of a porous medium is described. A core sample of the porous medium is secured in a core holder, which includes a first end and a second end. A model of the core sample and a pore volume of the core sample are obtained. A wetting phase is displaced from the core sample by supplying a non-wetting phase at one end of the core holder. The non-wetting phase is displaced from the core sample by supplying the wetting phase at one end of the core holder. A saturation profile of the core sample is determined based on cross-sectional images of the core sample. A wettability index value is calculated at least based on a comparison of the saturation profile and the model of the core sample.

Abstract: A directional drilling system comprises a driveshaft to couple to a drill string or a drill bit and an apparatus. The apparatus comprises an eccentric coupler disposed at the driveshaft and a coil coupled at one end to the eccentric coupler. In some embodiments, the coil comprises a fixed end and a rotating end. In response to a first transition temperature, the rotating end of the coil causes the eccentric coupler to rotate about the driveshaft, so as to move the driveshaft from a first orientation to a second orientation. Additional apparatus, methods, and systems are disclosed.

Abstract: Systems and methods are described herein for investigating a downhole formation using a nuclear magnetic resonance (NMR) tool. The tool includes multiple detectors spaced along an axis parallel to a length of the wellbore. While the tool is moving through the wellbore, NMR pulse sequences are applied to the formation and resulting NMR signals are detected by the detectors. The data obtained over a period of time by the multiple detectors are inverted together to obtain an indication of a parameter of the formation at multiple locations along the length of the wellbore.

Abstract: Systems, methods, and software for predicting total organic carbon (TOC) values are described. A representative method includes obtaining nuclear magnetic resonance (NMR) data and training a radial basis function (RBF) model based on the NMR data and measured total organic carbon (TOC) values. The method also includes obtaining subsequent NMR data and employing the trained RBF model to predict TOC values based at least in part on the subsequent NMR data. The method also includes storing or displaying the predicted TOC values.

Abstract: A method for determining a pulse duration T90 of a 90° pulse in a nuclear magnetic measuring method. A signal generator has a known generator resistance RS, wherein a coil has a coil impedance ZL with a coil resistance RL and a coil reactance XL, wherein a coupling circuit has an adjustable matching capacitance CM and an adjustable tuning capacitance CT, and wherein the medium has a Larmor precession having an angular Larmor frequency ?P. The time needed for determining the pulse duration T90 of the 90° pulse is reduced by the matching capacitance CM and the tuning capacitance CT being set so that the angular resonance frequency ?0 corresponds to the angular Larmor frequency ?P and by power matching being present between the signal generator and the coil. The coil resistance RL is determined and the pulse duration T90 is determined as a function of the coil resistance RL.

Abstract: A method for generating a model of a formation property includes acquiring a formation property measurement. A petrophysical quantity is inverted from the formation property measurement. A model is generated based on the inverted petrophysical quantity.

Abstract: Downhole fluid volumes of a geological formation may be estimated using nuclear magnetic resonance (NMR) measurements, even in organic shale reservoirs. Multi-dimensional NMR measurements, such as two-dimensional NMR measurements and/or, in some cases, one or more well-logging measurements relating to total organic carbon may be used to estimate downhole fluid volumes of hydrocarbons such as bitumen, light hydrocarbon, kerogen, and/or water. Having identified the fluid volumes in this manner or any other suitable manner from the NMR measurements, a reservoir producibility index (RPI) may be generated. The downhole fluid volumes and/or the RPI may be output on a well log to enable an operator to make operational and strategic decisions for well production.

Abstract: A method for measuring the flow rate of a multi-phase medium flowing through a measuring tube using a nuclear magnetic resonance flow meter can be used to measure the flow rate of a multi-phase medium in a simplified manner. For this purpose, a measuring device is used which implements, at the end of each pre-magnetization path, 2D tomography in the measurement tube cross-sectional plane with stratification in the z direction; the measurement tube cross-sectional plane is subdivided into layers that are thin compared to the measurement tube diameter; nuclear magnetic resonance measurements are carried out in every layer to determine measurement signals, using pre-magnetization paths of different lengths; the flow rates are measured in every layer based on the measurement signals; and the time is determined from the signal ratios of the amplitudes of the measurement signals in every layer.

Abstract: Various embodiments include a method for determining a viscosity for heavy oil in a formation by obtaining viscosity data and nuclear magnetic resonance (NMR) relaxation time distribution data for a plurality of oil samples. A correlation is determined between a set of viscosity data for the plurality of oil samples and an NMR relaxation time geometric mean for the plurality of oil samples. An NMR relaxation time geometric mean intrinsic value is determined based on the correlation, apparent hydrogen index, and TE. Electromagnetic energy may then be transmitted into a formation and NMR relaxation time distributions determined for oil in the formation based on secondary electromagnetic field responses associated with the electromagnetic energy. A viscosity of the oil in the formation may then be determined based a correlation between the set of viscosity data and the NMR relaxation time geometric mean intrinsic value of the distribution data.

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.