Abstract: An NMR sensor is configured to make NMR measurements of a fluid and includes a housing defining a chamber. A nonmagnetic cap is deployed in the chamber and divides the chamber into first and second regions. The cap is sized and shaped to define a fluid collector in the first region. A magnet assembly is deployed in the second region and is configured to generate a static magnetic field in the fluid collector. A radio frequency (RF) coil is interposed between the magnet assembly and the cap and is configured to generate an RF magnetic field in the fluid collector. Methods include using the sensor to make NMR measurements of multi-phase fluids such as drilling fluid.

Abstract: A method for detecting net relative motion between a nuclear magnetic resonance (NMR) tool and a specimen includes disposing the NMR tool and the specimen in sensory range of one another, causing the NMR tool to make NMR measurements of the specimen, and processing the NMR measurements to detect net relative motion between the NMR tool and the specimen.

Abstract: Methods and systems are provided that combine NMR and IR spectroscopy measurements on a rock sample to determine data representing at least one property of the rock sample. In one embodiment, cuttings can be split into first and second lots. Results of an NMR measurement performed on the first lot of cuttings without cleaning can be analyzed to determine pore volume of the cuttings. Results of an IR spectroscopy measurement performed on the second lot of cuttings after solvent cleaning can be analyzed to determine matrix density of the cuttings. Porosity can be determined from the pore volume and matrix density of the cuttings. In another embodiment, combined NMR and IR spectroscopy measurements can be performed on an unprepared rock sample (without solvent cleaning) to characterize properties of kerogen in the rock sample and porosity. In another aspect, a method is provided that employs multi-nucleic NMR measurements to determine porosity.

Abstract: 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.

Abstract: Methods and systems are provided that combine NMR and IR spectroscopy measurements on a rock sample to determine data representing at least one property of the rock sample. In one embodiment, cuttings can be split into first and second lots. Results of an NMR measurement performed on the first lot of cuttings without cleaning can be analyzed to determine pore volume of the cuttings. Results of an IR spectroscopy measurement performed on the second lot of cuttings after solvent cleaning can be analyzed to determine matrix density of the cuttings. Porosity can be determined from the pore volume and matrix density of the cuttings. In another embodiment, combined NMR and IR spectroscopy measurements can be performed on an unprepared rock sample (without solvent cleaning) to characterize properties of kerogen in the rock sample and porosity. In another aspect, a method is provided that employs multi-nucleic NMR measurements to determine porosity.

Abstract: An NMR well logging tool is provided that includes a sensor and associated electronic circuitry. The sensor includes an array of RF antenna elements. The electronic circuitry includes at least one low-power integrated circuit and a plurality of high-power modules corresponding the RF antenna elements of the array. Each high-power module is coupled to a corresponding RF antenna element of the array and includes an RF amplifier that is configured to amplify RF pulses generated by the at least one low-power integrated circuit and supplied thereto for transmission by the corresponding antenna element. In embodiments, the RF amplifier of each high-power module can include an H-bridge circuit or other suitable RF amplifier.

Abstract: Magnet design is provided. A method customizes a magnetic field uniformity of a magnet by introducing one or more gaps between pieces of the magnet assembly.

Abstract: An NMR sensor is configured to make NMR measurements of a fluid and includes a housing defining a chamber. A nonmagnetic cap is deployed in the chamber and divides the chamber into first and second regions. The cap is sized and shaped to define a fluid collector in the first region. A magnet assembly is deployed in the second region and is configured to generate a static magnetic field in the fluid collector. A radio frequency (RF) coil is interposed between the magnet assembly and the cap and is configured to generate an RF magnetic field in the fluid collector. Methods include using the sensor to make NMR measurements of multi-phase fluids such as drilling fluid.

Abstract: 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.

Abstract: An NMR well logging tool is provided that includes a sensor and associated electronic circuitry. The sensor includes an array of RF antenna elements. The electronic circuitry includes at least one low-power integrated circuit and a plurality of high-power modules corresponding the RF antenna elements of the array. Each high-power module is coupled to a corresponding RF antenna element of the array and includes an RF amplifier that is configured to amplify RF pulses generated by the at least one low-power integrated circuit and supplied thereto for transmission by the corresponding antenna element. In embodiments, the RF amplifier of each high-power module can include an H-bridge circuit or other suitable RF amplifier.

Abstract: 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.

Abstract: A system for drilling a borehole is disclosed. The system may include drill string having a bottom hole assembly a nuclear magnetic resonance tool within the bottom hole assembly, and a surface control system including a nuclear magnetic resonance measurement quality map. The control system may be configured to drill a borehole at a first set of drilling parameters and to receive motion properties from the nuclear magnetic resonance tool and adjust the drilling of the bore hole at a second set of drilling parameters. The surface control system may be further configured to adjust the drilling of the bore hole based on the motion properties from the nuclear magnetic resonance tool and the nuclear magnetic resonance measurement quality map.

Abstract: A method for fabricating a magnet on a nuclear magnetic resonance logging tool includes identifying a desired magnetic field strength at a predetermined depth of investigation, receiving a set of magnet segments configured for deployment on the logging tool in a magnet arrangement which make up a magnet array on the logging tool, processing a magnetic strength and an angular offset of selected magnet segments and their unique location in the magnet array to compute corresponding magnetic field strength solutions at the predetermined depth of investigation, selecting one magnet arrangement solution that minimizes a difference between the magnetic field strength solution and the desired magnetic field strength at the predetermined depth of investigation, and deploying the magnet segments on the logging tool according to the selected magnet arrangement solution to fabricate the magnet.

Abstract: Methods and systems are provided that combine NMR and IR spectroscopy measurements on a rock sample to determine data representing at least one property of the rock sample. In one embodiment, cuttings can be split into first and second lots. Results of an NMR measurement performed on the first lot of cuttings without cleaning can be analyzed to determine pore volume of the cuttings. Results of an IR spectroscopy measurement performed on the second lot of cuttings after solvent cleaning can be analyzed to determine matrix density of the cuttings. Porosity can be determined from the pore volume and matrix density of the cuttings. In another embodiment, combined NMR and IR spectroscopy measurements can be performed on an unprepared rock sample (without solvent cleaning) to characterize properties of kerogen in the rock sample and porosity. In another aspect, a method is provided that employs multi-nucleic NMR measurements to determine porosity.

Abstract: A system for drilling a borehole is disclosed. The system may include drill string having a bottom hole assembly a nuclear magnetic resonance tool within the bottom hole assembly, and a surface control system including a nuclear magnetic resonance measurement quality map. The control system may be configured to drill a borehole at a first set of drilling parameters and to receive motion properties from the nuclear magnetic resonance tool and adjust the drilling of the bore hole at a second set of drilling parameters. The surface control system may be further configured to adjust the drilling of the bore hole based on the motion properties from the nuclear magnetic resonance tool and the nuclear magnetic resonance measurement quality map.

Abstract: A method for fabricating a magnet on a nuclear magnetic resonance logging tool includes identifying a desired magnetic field strength at a predetermined depth of investigation, receiving a set of magnet segments configured for deployment on the logging tool in a magnet arrangement which make up a magnet array on the logging tool, processing a magnetic strength and an angular offset of selected magnet segments and their unique location in the magnet array to compute corresponding magnetic field strength solutions at the predetermined depth of investigation, selecting one magnet arrangement solution that minimizes a difference between the magnetic field strength solution and the desired magnetic field strength at the predetermined depth of investigation, and deploying the magnet segments on the logging tool according to the selected magnet arrangement solution to fabricate the magnet.

Abstract: A method to produce a magnet arrangement, the method having steps of selecting a depth of investigation to be achieved by a downhole tool, identifying a desired magnetic field strength at the depth of investigation, producing a set of magnets to be incorporated into the downhole tool, sorting the set of magnets based on a quality of each of the magnets and optimizing the set of magnets such that the quality of each of the magnets results, when arranged, in the desired magnetic field strength at the depth of investigation and wherein the optimizing minimizes a cost function of the set of magnets produced.

Abstract: A method for making NMR measurements includes, in one embodiment, using an NMR tool to acquire NMR measurements that are effected by relative motion of the NMR tool and/or the specimen under investigation. The NMR tool may include a plurality of permanent magnets and a plurality of radio frequency (RF) coils. The relative motion is estimated and used to modify an NMR inversion kernel which is in turn used to transform the NMR measurements into motion-corrected NMR measurements. Corresponding systems, devices, and apparatuses are also disclosed herein.

Abstract: Magnet design is provided. A method customizes a magnetic field uniformity of a magnet by introducing one or more gaps between pieces of the magnet assembly.

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.