Abstract: An apparatus comprising a data acquisition tool including NMR sensors, a data acquisition processor communicatively coupled with the NMR sensors, and a first memory storing instructions that cause the data acquisition processor to perform operations comprising acquiring data of earth formation fluid, varying at least one of a magnetic field gradient and an inter-echo time, and acquiring additional data. The apparatus further comprises a data processing unit comprising a second memory storing instructions that cause the data processor to perform operations comprising receiving data acquired by the data acquisition tool, constructing a mathematical model of the data, conducting a first inversion of the mathematical model to obtain a first set of NMR responses, performing a forward model of the first set of NMR responses obtained from the first inversion, conducting a second inversion to obtain a second set of NMR responses, and determining earth formation fluid properties.

Abstract: A method for determining earth formation rock and fluid properties comprising a data acquisition tool and a data acquisition processor, coupled with NMR sensors, and a first memory; transmitting acquired 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), wherein the EPR includes both partially polarized and fully polarized bins; inverting the EPR to obtain an apparent transverse relaxation time (T2app) distribution, wherein the T2app distribution includes fully and partially polarized state echo train data; 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; determining earth formation fluid properties and displaying the properties on a display screen.

Abstract: In some embodiments, an apparatus, system, and method may operate to transmit, using a first transceiver antenna, a common signal into a geological formation, and to receive in response to the transmitting, at the first transceiver antenna, a first corresponding nuclear magnetic resonance (NMR) signal from a first volume of the formation. Additional activity may include receiving, in response to the transmitting, at a second transceiver antenna spaced apart from the first transceiver antenna, the common signal transformed by the formation into a received resistivity signal, as well as transmitting, using the second transceiver antenna, a second corresponding NMR signal into a second volume of the formation different from the first volume of the formation. Additional apparatus, systems, and methods are disclosed.

Abstract: Apparatus, method and system for processing and interpreting nuclear magnetic resonance (NMR) data acquired for a formation from within a subterranean wellbore that includes independently obtaining D?T1 and D?T2 from the same set of NMR data using a dual step independent 2D inversion method that provides adequate resolution in all dimensions for T1, T2, and D distributions.

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: 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 method for monitoring the oleophilic fluid to aqueous fluid ratio of a drilling fluid includes selecting a sample of the drilling fluid that has been recirculated, measuring the NMR response of the sample of the drilling fluid and determining the oleophilic fluid to aqueous fluid ratio of the drilling fluid based at least in part on the NMR response.

Abstract: Downhole nuclear magnetic resonance (NMR) methods that utilize oleophilic nanoparticle may allow for differentiation of light oil and oil-based filtrates. For example, a method may involve drilling a wellbore penetrating a subterranean formation using an oil-based drilling fluid that comprises an oil base fluid and a plurality of oleophilic nanoparticles; performing a plurality of NMR measurements at a plurality of depths of investigation (DOI) of a near-wellbore portion of the subterranean formation; and producing an invasion profile of an oil-based drilling fluid filtrate into the near-wellbore portion of the subterranean formation based on the plurality of NMR measurements.

Abstract: 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.

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: Various embodiments include nuclear magnetic resonance (MR) sensor array systems and methods are disclosed. One such system includes a downhole casing having at least one MR sensor array peripherally coupled to an outside of the casing. At least one MR sensor array can include an MR sensor configured to monitor a cement/fluid mix composition while the cement is setting.

Abstract: Analyzing crude oils and, more specifically, indirectly measuring asphaltene concentration in crude oils may be performed via nuclear magnetic resonance (NMR) techniques. For example, determining the asphaltene concentration of a crude oil sample having an unknown concentration of asphaltene and having the API gravity of about 20 to about 41 may be achieved by applying a measured NMR property of the unknown sample to a mathematical regression for asphaltene concentration in crude oil as a function of an NMR property according to the following equation where C is the asphaltene concentration, k is the Huggins constant that describes the solvent quality, [?] is the intrinsic viscosity.

Abstract: Apparatus, method and system for processing and interpreting nuclear magnetic resonance (NMR) data acquired for a formation from within a subterranean wellbore that includes independently obtaining D?T1 and D?T2 from the same set of NMR data using a dual step independent 2D inversion method that provides adequate resolution in all dimensions for T1, T2, and D distributions.

Abstract: Formation testing systems and methods may inject fluids into a formation to initiate fractures and facilitate measurements of various formation properties. In accordance with certain disclosed embodiments, the injection tools are further provided with nuclear magnetic resonance (NMR) sensors to monitor the injected fluids and provide measurements of near-borehole fracture orientations and volumes. Contrast agents and/or magnetic resonance imaging (MRI) techniques may be employed. The fluid injection may occur via an extendible isolation pad, via a fracturing jet, or via an injection port in an isolated region of the borehole. The systems may employ pressure monitoring in conjunction with the NMR sensors to further enhance estimates of formation and fracture properties.

Abstract: Systems, methods, and software for estimating the viscosity of a subterranean fluid based on NMR logging data are described. In some aspects, a viscosity model relates subterranean fluid viscosity to apparent hydrogen index. An apparent hydrogen index value for a subterranean region is computed based on nuclear magnetic resonance (NMR) logging data acquired from a subterranean region. A subterranean fluid viscosity value is computed for the subterranean region based on the viscosity model and the apparent hydrogen index value.

Abstract: Various disclosed nuclear magnetic resonance (NMR) logging systems and methods employ a plurality of NMR sensors, including atomic magnetometers, mounted on pads. Certain method embodiments include: utilizing the Earth magnetic field to pre-polarize the protons in a formation; utilizing a plurality of atomic magnetometers to obtain NMR measurements; and determining at least one characteristic relaxation time of the formation. The NMR sensor may optionally include a permanent magnet assembly.

Abstract: Systems, methods, and software for predicting a pore throat size distribution are described. A representative method includes ohtaining a nuclear magnetic resonance (NMR) relaxation-time distribution data set. The method also includes training a radial basis function (RBF) model based on the NMR relaxation-time distribution data set and a measured pore throat size distribution data set. The method also includes obtaining a subsequent NMR relaxation-time distribution data set. The method also includes employing the trained RBI: model to predict a pore throat size distribution data set based at least in part on the sUbsequent NMR relaxation-time distribution data set. The method also includes storing or displaying a predicted pore throat size distribution corresponding to the predicted pore throat size distribution data set. The predicted pore throat size distribution is associated with a rock sample or subsurface formation volume.

Abstract: Various embodiments include apparatus and methods to conduct testing related to the disposition of measuring tools downhole in a borehole, where the measuring tools are deployed to perform testing to evaluate properties of regions in the borehole. A plurality of test analyses on data collected from operating a measuring device of a measuring tool in the borehole can be used to determine whether the measuring device is in casing or out of casing. Additional apparatus, systems, and methods are disclosed.

Abstract: Downhole nuclear magnetic resonance (NMR) methods that utilize oleophilic nanoparticle may allow for differentiation of light oil and oil-based filtrates. For example, a method may involve drilling a wellbore penetrating a subterranean formation using an oil-based drilling fluid that comprises an oil base fluid and a plurality of oleophilic nanoparticles; performing a plurality of NMR measurements at a plurality of depths of investigation (DOI) of a near-wellbore portion of the subterranean formation; and producing an invasion profile of an oil-based drilling fluid filtrate into the near-wellbore portion of the subterranean formation based on the plurality of NMR measurements.

Abstract: Various embodiments include apparatus and methods to conduct testing related to the disposition of measuring tools downhole in a borehole, where the measuring tools are deployed to perform testing to evaluate properties of regions in the borehole. A plurality of test analyses on data collected from operating a measuring device of a measuring tool in the borehole can be used to determine whether the measuring device is in casing or out of casing. Additional apparatus, systems, and methods are disclosed.