Abstract: Methods and systems are provided for optimizing well-logging using an optimized wait time determined by analysis nuclear magnetic resonance data to achieve faster and better quality borehole evaluation. The method comprises performing a nuclear magnetic resonance pre-log testing; identifying a wait time for a portion of a signal from the pre-log testing with a long T1 and T2, value at each depth of the pre-log testing, wherein T1 is defined as a longitudinal relaxation time and T2 is a transverse relaxation time ascertained from the nuclear magnetic resonance prelog testing; and constructing a logging program with a logging program wait time being consistent with the wait time identified.

Abstract: Aqueous liquid which has been in contact with a subterranean geological formation, especially a hydrocarbon reservoir, is examined in order to detect or measure viscosifying polymer therein, by flowing a sample of the liquid through a constriction thereby causing extensional flow and alignment of any polymer molecules with the flow, and examining the solution for birefringence of aligned polymer molecules. The amount of birefringence is determined from intensity of light which has passed through the solution relative to intensity of the light source.

Abstract: Methods for improved interpretation of NMR data acquired from industrial samples by simultaneously detecting more than one resonant nucleus without removing the sample from the sensitive volume of the NMR magnet or radio frequency probe are disclosed. In other aspects, the present disclosure provides methods for robust imaging/analysis of spatial distribution of different fluids (e.g., 1H, 23Na, 19F) within a core or reservoir rock. NMR data may be interpreted in real-time during dynamic processes to enable rapid screening, e.g. of enhanced oil recovery techniques and products and/or to provide improved interpretation of well-logs. Measurements of resonant nuclei other than 1H may be performed in the laboratory or downhole with a NMR logging tool. In other aspects, the present disclosure describes a novel kernel function to extract values for underlying parameters that define relaxation time behavior of a quadrupolar nucleus.

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: 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: Systems and methods are provided for investigating a downhole formation using a nuclear magnetic resonance (NMR) tool having two or more radio frequency receiving coils. While the tool is moving through the borehole, the formation is magnetized and resulting signals are obtained. In accordance with the present approach, the acquired signals can be resolved azimuthally and can be reconstructed to obtain an indication of a parameter of the formation at multiple locations along the length of the borehole.

Abstract: Aqueous liquid which has been in contact with a subterranean geological formation, especially a hydrocarbon reservoir, is examined in order to detect or measure viscosifying polymer therein, by flowing a sample of the liquid through a constriction thereby causing extensional flow and alignment of any polymer molecules with the flow, and examining the solution for birefringence of aligned polymer molecules. The amount of birefringence is determined from intensity of light which has passed through the solution relative to intensity of the light source.

Abstract: Methods for improved interpretation of NMR data acquired from industrial samples by simultaneously detecting more than one resonant nucleus without removing the sample from the sensitive volume of the NMR magnet or radio frequency probe are disclosed. In other aspects, the present disclosure provides methods for robust imaging/analysis of spatial distribution of different fluids (e.g., 1H, 23Na, 19F) within a core or reservoir rock. NMR data may be interpreted in real-time during dynamic processes to enable rapid screening, e.g. of enhanced oil recovery techniques and products and/or to provide improved interpretation of well-logs. Measurements of resonant nuclei other than 1H may be performed in the laboratory or downhole with a NMR logging tool. In other aspects, the present disclosure describes a novel kernel function to extract values for underlying parameters that define relaxation time behavior of a quadrupolar nucleus.

Abstract: Apparatus and methods for characterizing hydrocarbons in a subterranean formation include obtaining a sample of the subterranean formation; measuring, uphole, the porosity of the sample; using a nuclear magnetic resonance (NMR) tool downhole in the borehole, sending NMR pulse sequences configured for formation pore size and measuring NMR signals that characterize the formation at a location in the formation; analyzing the signals to find a gas porosity of the formation at the location; and determining a hydrogen index (HIg) of the subterranean formation from the gas porosity and from the porosity of the sample. The obtained HIg may then be used in conjunction with downhole NMR measurements to find corrected gas porosities at locations of the formation.

Abstract: An NMR method and apparatus for analyzing a sample of interest applies a static magnetic field together with RF pulses of oscillating magnetic field across a sample volume that encompasses the sample of interest. The RF pulses are defined by a pulse sequence that includes a plurality of measurement segments configured to characterize a plurality of relaxation parameters related to relaxation of nuclear magnetization of the sample of interest. Signals induced by the RF pulses are detected in order to derive the relaxation parameters. The measurement segments of the pulse sequence include at least one first-type measurement segment configured to characterize relaxation of spin-lattice interaction between nuclei of the sample of interest in a rotating frame (T1?) at a predefined frequency. The T1? parameter can be measured in conjunction with the measurement of other relaxation and/or diffusion parameters as part of multidimensional NMR experiments.

Abstract: 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 an NMR measurement on the hydrocarbon-containing fluid to obtain NMR data. A non-NMR tool, such as an optical tool, is used to conduct additional measurements on the hydrocarbon-containing fluid and to obtain non-NMR data on the fluid. An indication of the composition of the fluid can be determined by using the NMR data and the non-NMR data in an inversion process.

Abstract: Systems and methods are provided for investigating a downhole formation using a nuclear magnetic resonance (NMR) tool having two or more radio frequency receiving coils. While the tool is moving through the borehole, the formation is magnetized and resulting signals are obtained. In accordance with the present approach, the acquired signals can be resolved azimuthally and can be reconstructed to obtain an indication of a parameter of the formation at multiple locations along the length of the borehole.

Abstract: Methods for the determination of the Total Gas in Place (TGiP) in gas-bearing formations are provided. Aspects of the subject disclosure also relate to the determination of the TGiP from nuclear magnetic resonance (NMR) logs alone or in combination other well logs.

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: Apparatus and methods for characterizing hydrocarbons in a subterranean formation including sending and measuring NMR signals; analyzing the signals to form a distribution; and estimating a property of a formation from the distribution, wherein the sending comprises pulse sequences configured for a formation pore size, and wherein the computing comprises porosity. Apparatus and methods for characterizing hydrocarbons in a subterranean formation including sending and measuring NMR signals; analyzing the signals to form a distribution; and estimating a property of a formation from the distribution, wherein the formation comprises a distribution of pore sizes of about 10 nm or more, and wherein the computing comprises natural gas composition.

Abstract: 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 an NMR measurement on the hydrocarbon-containing fluid to obtain NMR data. A non-NMR tool, such as an optical tool, is used to conduct additional measurements on the hydrocarbon-containing fluid and to obtain non-NMR data on the fluid. An indication of the composition of the fluid can be determined by using the NMR data and the non-NMR data in an inversion process.

Abstract: An NMR method and apparatus for analyzing a sample of interest applies a static magnetic field together with RF pulses of oscillating magnetic field across a sample volume that encompasses the sample of interest. The RF pulses are defined by a pulse sequence that includes a plurality of measurement segments configured to characterize a plurality of relaxation parameters related to relaxation of nuclear magnetization of the sample of interest. Signals induced by the RF pulses are detected in order to derive the relaxation parameters. The measurement segments of the pulse sequence include at least one first-type measurement segment configured to characterize relaxation of spin-lattice interaction between nuclei of the sample of interest in a rotating frame (T1?) at a predefined frequency. The T1? parameter can be measured in conjunction with the measurement of other relaxation and/or diffusion parameters as part of multidimensional NMR experiments.

Abstract: A method for determining particle size distribution of a subsurface rock formation using measurements of at least one nuclear magnetic resonance property made from within a wellbore penetrating the rock formation includes determining a distribution of nuclear magnetic relaxation times from the measurements of the at least one nuclear magnetic resonance property. A surface relaxivity of the formation is determined from measurements of a formation parameter. The relaxation time distribution and surface relaxivity are used to determine the particle size distribution.

Abstract: A method for determining surface relaxivity of a rock formation in a wellbore includes using measurements of nuclear magnetic resonance properties of the rock formation made from within a wellbore penetrating the rock formations includes determining nuclear magnetic relaxation properties from the measurements of the nuclear magnetic resonance properties. A diffusion property of the rock formation is determined from the measurements of the nuclear magnetic resonance properties. The surface relaxivity of the rock formation is determined from the relaxation properties and the diffusion property. The surface relaxivity and other nuclear magnetic resonance properties are used to infer wettability and/or fluid saturation of the rock formations.

Abstract: A method for determining particle size distribution of a subsurface rock formation using measurements of at least one nuclear magnetic resonance property made from within a wellbore penetrating the rock formation includes determining a distribution of nuclear magnetic relaxation times from the measurements of the at least one nuclear magnetic resonance property. A surface relaxivity of the formation is determined from measurements of a formation parameter. The relaxation time distribution and surface relaxivity are used to determine the particle size distribution.