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.

In accordance with embodiments of the present disclosure, a nuclear magnetic resonance (NMR) logging tool for use in wellbore logging operations is provided. The NMR logging tool features a three-part permanent magnet arrangement that reduces the attractive force between the NMR tool and casing, allowing the NMR tool to be lowered through wellbores of any size. Additionally, the disclosed arrangement of permanent magnets in the NMR tool may facilitate an effective pre-polarization of portions of the formation at different logging speeds. Further, the disclosed arrangement of permanent magnets in the NMR tool may provide a uniform or substantially uniform static magnetic field within the antenna window of the radio frequency (RF) antenna used to perform the measurements. The second magnet may be positioned between the first and third magnets in a longitudinal direction along the NMR tool, and a radio frequency (RF) antenna may be disposed adjacent the first magnet.

An NMR system includes a radio frequency (RF) NMR application-specific integrated circuit (ASIC) chip configured to generate an RF output signal and a rectifier configured to receive the RF output signal and convert the RF output signal to (a) a direct current (DC) pulsed field gradient (PFG) signal or (b) a DC trigger signal for at least one of (i) activating at least one component of an NMR system external to the NMR RF ASIC chip and (ii) synchronizing at least one component of an NMR system external to the NMR RF ASIC chip.

A microwave moisture sensor for agricultural materials, such as grains and nuts, is disclosed herein that includes a material sample holder having a substantially cylindrical cavity formed therein. The meter assembly further includes a transmitting antenna on a side of the sample holder and a receiving antenna on a side of sample holder directly opposite the transmitting antenna wherein the sample holder is located between the two antennas, the receiving antenna configured to receive a transmitted microwave through the sample holder.

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.

Logging-while-drilling (LWD) tools may include multiple instruments interleaved into a compact configuration in a single drill string section that may be capable of nuclear magnetic resonance, resistivity, porosity, gamma density measurements, or any combination thereof. For example, a LWD tool may include a drill collar section containing: a nuclear magnetic resonance (NMR) electronics module and an NMR sensor module interleaved with a nuclear source and at least one nuclear detector.

The effect of a treatment on a rock sample or sub-sample extracted from the rock sample can be analyzed through computed tomography (CT). To determine the effect of a treatment of a rock sample or the sub-sample, pre-treatment and post-treatment CT images of the rock sample or the sub-sample are captured. Further, the pre-treatment CT images and post-treatment CT images of the rock sample or the sub-sample are compared based on one or more alignment markers added to the rock sample or the sub-sample. In some embodiments, pre-treatment and post-treatment CT scans of an extracted sub-sample provide higher-resolution information regarding the effect of the treatment. Further, pre-treatment and post-treatment CT scans of a rock sample with a restored sub-sample may be considered and may provide additional information regarding the effect of the treatment on the rock sample or the sub-sample.

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 NMR measurements on the hydrocarbon-containing fluid to obtain NMR data. A non-NMR tool, such as an optical tool, is used to conduct additional measurements and to obtain non-NMR data on the fluid. The methods further include determining an indication of the composition of the fluid by using the NMR data and normalizing the indication of the composition of the fluid using the non-NMR data.

A method includes screening heterogeneity of a rock sample using nuclear magnetic resonance testing to determine a composition of the rock sample, drilling at least one smaller rock sample representative of the determined composition, and testing the at least one smaller rock sample with mercury injection capillary pressure to obtain a capillary pressure distribution of the at least one smaller rock sample. The method further includes decomposing a T.sub.2 distribution from the nuclear magnetic resonance testing and the capillary pressure distribution using Gaussian fitting to identify multiple pore systems, where the small ends of the Gaussian fitted T.sub.2 distribution and the Gaussian fitted capillary pressure distribution are overlapped for at least one of the identified pore systems.

A method for evaluating drilling fluid includes making an NMR measurement of a sample of the drilling fluid and inverting the measurements to compute a corresponding T1T2 plot. The T1T2 plot is in turn evaluated to characterize the drilling fluid. In one embodiment, a stability index of the fluid may be computed from multiple NMR measurements made while aging the sample.