Browsing by Author "Singer, Philip M."

Now showing 1 - 6 of 6
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    Determination of fluid-phase-specific petrophysical properties of geological core for oil, water and gas phases
    (2024-03-05) Vinegar, Eva; Singer, Philip M.; Hirasaki, George J.; Chen, Zeliang; Wang, Xinglin; Vinegar, Harold J.; Rice University; Vinegar Technologies LLC; United States Patent and Trademark Office
    The following invention is used for determining the relative permeability of a fluid in a rock for three different phases: water, oil, and gas, in both conventional and unconventional formations. The permeability of a phase describes how much it can flow in porous media given a pressure gradient and is useful in evaluating reservoir quality and productivity. The following invention is a method to determine the three-phase relative permeabilities in both conventional and unconventional formations using NMR restricted diffusion measurements on core with NMR-active nuclei, combined with centrifugation of the core. In addition, the tortuosity, pore size (surface-to-volume ratio), fluid-filled porosity, and permeability is determined for each of the three phases in a rock.
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    Distinguishing the Effect of Rock Wettability from Residual Oil on Foam Generation and Propagation in Porous Media
    (American Chemical Society, 2021) Amirmoshiri, Mohammadreza; Wang, Xinglin; Bai, Chutian; Tewari, Raj Deo; Xie, Sheena Xina; Bahrim, Ridhwan Zhafri Kamarul; Singer, Philip M.; Farajzadeh, Rouhi; Biswal, Sibani Lisa; Hirasaki, George. J.
    One of the common challenges of applying foam for enhanced oil recovery is the foam instability in the presence of crude oil and nonwater-wet surfaces. In this experimental study, we systematically distinguish the effect of rock surface wettability from that of crude oil saturation on foam rheology under reservoir conditions. Neutral-wet Berea and reservoir sandstone cores are prepared by aging with crude oil, followed by the wettability index measurements. Transient foam generation and steady-state foam quality scans are conducted in neutral-wet cores, with/without water-flood residual oil. Nuclear magnetic resonance imaging is also utilized to measure the remaining oil saturation at the end of the foam-flood. It is shown that strong foam can be generated in a neutral-wet core with no residual oil because of the solubilization of the adsorbed crude oil components and the wettability alteration toward more water-wet conditions. However, in a neutral-wet core containing residual oil, foam generation is initially hindered. Foam generation occurs after injecting several pore volumes of surfactant solution and increasing the superficial velocity to overcome the minimum pressure gradient required for in situ foam generation. The findings from this study suggest that surface wettability in the presence of bulk oil saturation significantly affects transient foam generation. The final steady-state foam strength becomes comparable to the water-wet and oil-free case once the residual oil saturation is adequately reduced.
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    Emergence of the spin polarized domains in the kagome lattice Heisenberg antiferromagnet Zn-barlowite (Zn0.95Cu0.05)Cu3(OD)6FBr
    (Springer Nature, 2022) Yuan, Weishi; Wang, Jiaming; Singer, Philip M.; Smaha, Rebecca W.; Wen, Jiajia; Lee, Young S.; Imai, Takashi
    Kagome lattice Heisenberg antiferromagnets are known to be highly sensitive to perturbations caused by the structural disorder. NMR is a local probe ideally suited for investigating such disorder-induced effects, but in practice, large distributions in the conventional one-dimensional NMR data make it difficult to distinguish the intrinsic behavior expected for pristine kagome quantum spin liquids from disorder-induced effects. Here we report the development of a two-dimensional NMR data acquisition scheme applied to Zn-barlowite (Zn0.95Cu0.05)Cu3(OD)6FBr kagome lattice, and successfully correlate the distribution of the low energy spin excitations with that of the local spin susceptibility. We present evidence for the gradual growth of domains with a local spin polarization induced by 5% Cu2+ defect spins occupying the interlayer non-magnetic Zn2+ sites. These spin-polarized domains account for ~60% of the sample volume at 2 K, where gapless excitations induced by interlayer defects dominate the low-energy sector of spin excitations within the kagome planes.
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    Method for determining the composition of natural gas liquids, mean pore-size and tortuosity in a subsurface formation using NMR
    (2021-08-24) Vinegar, Harold J.; Singer, Philip M.; Hirasaki, George J.; Chen, Zeliang; Wang, Xinglin; Rice University; Vinegar Technologies LLC; United States Patent and Trademark Office
    New methods for determining the volumetric composition and saturation of methane and NGLs (natural gas liquids: ethane, propane, butane, and pentane) in a petroleum reservoir combining NMR (nuclear magnetic resonance) logging and NMR core analysis and for determining the mean pore-size and tortuosity of the light hydrocarbon-filled porosity in a petroleum reservoir using NMR core analysis.
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    Method of estimating permeability using NMR diffusion measurements
    (2024-03-19) Vinegar, Harold J.; Singer, Philip M.; Hirasaki, George J.; Chen, Zeliang; Wang, Xinglin; Vinegar, Eva; Rice University; Vinegar Technologies LLC; United States Patent and Trademark Office
    This invention is useful for determining the permeability of a geological formation using 1H NMR diffusion measurements acquired in the laboratory and using downhole 1H NMR well logging. The current technology for obtaining formation permeability downhole using NMR is not adequate for low-permeability, unconventional source rock formations with high organic content. This new method uses laboratory 1H NMR diffusion measurements for creating continuous downhole well logs of the mobile-hydrocarbon permeability of the hydrocarbon-filled pore space of downhole geological formations.
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    Revisiting Fundamentals of NMR Relaxation in Bulk and Confined Fluids
    (2022-04-22) Valiya Parambathu, Arjun; Chapman, Walter G.; Hirasaki, George J.; Asthagiri, Dilip; Singer, Philip M.
    Nuclei with non-zero spin, such as the hydrogen nuclei, act like tiny “magnets” that can be excited by suitably applied external magnetic fields. The phenomena by which the “magnets” return to equilibrium is termed Nuclear Magnetic Resonance (NMR) relaxation, a process characterized by two time constants T1 and T2, corresponding to relaxation in the longitudinal and transverse directions, respectively. T1 and T2 are dependent on the equilibrium structure and dynamics of the system. This feature provides an avenue to probe matter non-destructively, with applications ranging from medical imaging to well logging. The traditional interpretation of T1 and T2 in liquids has long relied on rather severe assumptions about the fluid structure and dynamics, such as treating molecules as hard spheres and the magnetic dipoles as freely rotating. In this work, we remove these approximations by leveraging atomistic simulations that can accurately predict the structure and dynamics of fluids. By relating the auto-correlation of magnetic dipole-dipole interactions to NMR relaxation, we revisit the interpretation of NMR relaxation in bulk and confined fluids. In the fast-motion regime, where fluid viscosity is low and traditional theories would be expected to hold, we instead find that the relaxation is sensitively dependent on the shape and internal motions of the molecule. To explore the slow-motion regime where fluid viscosity is high, we studied heptane confined in a polymer matrix and the glass-former glycerol across a range of temperatures. For heptane in a polymer matrix, the simulated relaxation times show excellent agreement with measurements; importantly, we find that confinement greatly enhances the NMR relaxation, and there is no need to invoke the physics of paramagnetism, as is often done. For glycerol, simulations once again capture measurements, and in the high viscosity regime, in contrast with polymers, the relaxation rate decreases due to the hydrogen bonding network. In the presence of a genuine paramagnetic ion, Gadolinium (III), a well-known contrast agent used in Magnetic Resonance Imaging (MRI), simulations can capture the NMR relaxivity at MRI frequencies, with expected discrepancies at low frequencies attributable to electron spin relaxation effects. Overall, this work exposes the limitations of traditional theories but also shows that by using theory and simulations, one can enhance the interpretation of available experiments, opening new avenues to probe matter using relaxation methods.