Abstract: A method for estimating a property of an earth formation is provided. At least one porosity dataset is received. The porosity dataset is analysed to determine pore-throat size distribution. A NMR measurements dataset is received from a NMR tool. The dataset is analyzed to determine a distribution of a first relaxation time versus a second relaxation time. Distribution of a ratio of the first relaxation time to the second relaxation time is determined by calculating a ratio between a geometric mean of the first relaxation and the second relaxation time. A threshold for the ratio of the first relaxation time to the second relaxation time is selected. The threshold indicates a value of the ratio corresponding to pore sizes not contributing to property of the formation. The property of the formation is determined using the determined threshold for the ratio of the first relaxation time to the second relaxation time.

Abstract: A method for estimating a property of an earth formation is provided. At least one porosity dataset is received. The porosity dataset is analysed to determine pore-throat size distribution. A NMR measurements dataset is received from a NMR tool. The dataset is analyzed to determine a distribution of a first relaxation time versus a second relaxation time. Distribution of a ratio of the first relaxation time to the second relaxation time is determined by calculating a ratio between a geometric mean of the first relaxation and the second relaxation time. A threshold for the ratio of the first relaxation time to the second relaxation time is selected. The threshold indicates a value of the ratio corresponding to pore sizes not contributing to property of the formation. The property of the formation is determined using the determined threshold for the ratio of the first relaxation time to the second relaxation time.

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: 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: 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: 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.