Abstract: Methods and systems are provided that employ a combination of dielectric dispersion measurement(s) and Nuclear Magnetic Resonance (NMR) measurement(s) to determine data that characterizes tortuosity of rock and data that characterizes tortuosity of fluid phases in the rock independently from one another.

Abstract: Methods and systems are provided that employ a combination of dielectric dispersion measurement(s) and Nuclear Magnetic Resonance (NMR) measurement(s) to determine data that characterizes tortuosity of rock and data that characterizes tortuosity of fluid phases in the rock independently from one another.

Abstract: A method for determining a wettability of a subterranean formation (or formation core) includes either deploying a nuclear magnetic resonance (NMR) logging tool in a subterranean wellbore or deploying a formation core sample in a laboratory based NMR tool. NMR measurements of the formation (or formation core) are obtained and used to compute the wettability. The NMR measurements are processed to generate a two dimensional diffusion relaxation map (a D/T2 map) which is in turn processed to compute the wettability.

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 NMR logging tool is provided and disposed in a wellbore at some desired depth. Packers are provided and actuated to hydraulically isolate a section of the wellbore and form a cavity between the NMR logging tool and the wall of the isolated section of the wellbore. The cavity is evacuated until a first desired pressure within the cavity is attained. Fluid is injected into the cavity until a second desired pressure within the cavity is attained. A plurality of NMR measurements is made on the region of the formation, each of the plurality of measurements being made at different times. Formation properties are inferred using the measurements. A baseline NMR measurement may be made when a first desired pressure is attained. A time-zero NMR measurement may be made when a second desired pressure is attained. Similar measurements may be made in a laboratory on a sample.

Abstract: A measurement device makes measurements on a region of investigation in which a native fluid or complex fluid (e.g., emulsified fluid) has been replaced by a fluid of different viscosity. Various methods such as core flooding, pressure cycling, centrifuging, or imbibition may be used to replace the native fluid. The replacement fluid may include alkanes, alkenes, or some combination of those, and is preferably non-polar. The replacement fluid may mix with the native fluid within the pores to produce a mixture having a different viscosity than the native fluid. Measurements can be made on a sample in a lab or on an isolated region of a subsurface formation. Standard measurement techniques such as the Amott-Harvey technique or the United States Bureau of Mines technique may be used. Alternatively, NMR measurements may be performed. A parameter such as wettability and relaxivity is estimated using data obtained by the measurement device.

Abstract: For a given medium, a property may be inferred based on nuclear magnetic resonance (NMR) data. NMR data that includes two or more different NMR signals are used. Differences between any particular two of the two or more different NMR decays are computed and a distribution is produced based on the computed differences. The property of the medium may be inferred using the produced distribution. The produced distribution features the change in a parameter. The NMR distributions may be T2 distributions, T1 distributions, diffusion, or any other type of NMR data. The NMR data may be acquired: at different times, for different levels of invasion, before and after water flooding, or for different saturation states. The inferred property may pertain to the oil and gas industry, material analysis, medicine, pharmaceuticals, the process industry, or the food industry. For example, the inferred property may be the porosity of a subsurface formation.

Abstract: A permanent monitoring tool is provided and disposed in a wellbore. Measurements are made at different times using the permanent monitoring tool on a region of a formation penetrated by the wellbore. One or more properties of the formation are inferred at one or more depths of investigation within the region using the measurements. Any changes in the one or more inferred formation properties are determined and one or more reservoir management decisions are made based on the determined changes. The well may be an observation well, an injector well, or a production well. The permanent monitoring tool may be a magnetic resonance tool or an electromagnetic tool. The measurements may be stacked to improve the signal-to-noise ratio of the signal. Different depths of investigation may be selected using antenna arrays of different lengths. The inferred properties may be saturation or resistivity. Conductive or non-conductive casing may be used.

Abstract: A method for determining a wettability of a subterranean formation (or formation core) includes either deploying a nuclear magnetic resonance (NMR) logging tool in a subterranean wellbore or deploying a formation core sample in a laboratory based NMR tool. NMR measurements of the formation (or formation core) are obtained and used to compute the wettability. The NMR measurements are processed to generate a two dimensional diffusion relaxation map (a D/T2 map) which is in turn processed to compute the wettability.

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: For a given medium, a property may be inferred based on nuclear magnetic resonance (NMR) data. NMR data that includes two or more different NMR signals are used. Differences between any particular two of the two or more different NMR decays are computed and a distribution is produced based on the computed differences. The property of the medium may be inferred using the produced distribution. The produced distribution features the change in a parameter. The NMR distributions may be T2 distributions, T1 distributions, diffusion, or any other type of NMR data. The NMR data may be acquired: at different times, for different levels of invasion, before and after water flooding, or for different saturation states. The inferred property may pertain to the oil and gas industry, material analysis, medicine, pharmaceuticals, the process industry, or the food industry. For example, the inferred property may be the porosity of a subsurface formation.

Abstract: A permanent monitoring tool is provided and disposed in a wellbore. Measurements are made at different times using the permanent monitoring tool on a region of a formation penetrated by the wellbore. One or more properties of the formation are inferred at one or more depths of investigation within the region using the measurements. Any changes in the one or more inferred formation properties are determined and one or more reservoir management decisions are made based on the determined changes. The well may be an observation well, an injector well, or a production well. The permanent monitoring tool may be a magnetic resonance tool or an electromagnetic tool. The measurements may be stacked to improve the signal-to-noise ratio of the signal. Different depths of investigation may be selected using antenna arrays of different lengths. The inferred properties may be saturation or resistivity. Conductive or non-conductive casing may be used.

Abstract: Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T2). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Abstract: A NMR logging tool is provided and disposed in a wellbore at some desired depth. Packers are provided and actuated to hydraulically isolate a section of the wellbore and form a cavity between the NMR logging tool and the wall of the isolated section of the wellbore. The cavity is evacuated until a first desired pressure within the cavity is attained. Fluid is injected into the cavity until a second desired pressure within the cavity is attained. A plurality of NMR measurements is made on the region of the formation, each of the plurality of measurements being made at different times. Formation properties are inferred using the measurements. A baseline NMR measurement may be made when a first desired pressure is attained. A time-zero NMR measurement may be made when a second desired pressure is attained. Similar measurements may be made in a laboratory on a sample.

Abstract: Methods are provided for separating oil and water signals in multidimensional nuclear magnetic resonance (NMR) maps. In one embodiment, separate multidimensional NMR maps are provided for oil and water content. In another embodiment, an oil-water boundary and a water-gas boundary are generated on a D-T2 map. The boundaries may be curved boundaries or lines.

Abstract: Systems and methods for quickly determining wettability using a derived relationship between the two Nuclear Magnetic Resonance (NMR) relaxation times T1,oil and T2,oil combined with downhole or laboratory based NMR measurements. The derived relationship between T1,oil, T2,oil and wettability can be developed empirically for example from core-sample data. Once the relationship is defined, it can be used in the field or laboratory to quickly determine wettability from NMR measurements that measure T1,oil and T2,oil directly, or a function depending on them.

Abstract: Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T2). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.