Methods for determining a volume of stored gas within a rock sample includes loading a rock sample into an overburden cell. A hydrocarbon gas at a gas pressure is applied to the rock sample and a confining fluid at a confining pressure is applied to the overburden cell. The confining pressure and the gas pressure are increased until a first pressure and temperature condition is met. With the rock sample maintained at the first temperature and pressure condition, a nuclear magnetic resonance spectrometer is used to scan the rock sample and measure a hydrocarbon gas volume within the rock sample. This measured hydrocarbon gas volume is then corrected using a Real Gas Index to determine the volume of stored gas within the rock sample.

A nuclear magnetic resonance (NMR) logging system and method is disclosed. The method may include obtaining an NMR well log, a measured downhole temperature, and at least one rock sample for a formation in a subsurface region. The method may further include determining an NMR distribution for each sample and selecting a set of samples based on the determined NMR distribution. For each selected sample, the method may further include determining a first parameter of the NMR distribution, a regression parameter of a relationship, and a first and second fractal parameters of the NMR distribution. The method may further include determining a second parameter of the NMR distribution based on the first and second fractal parameters, the regression parameter, and the downhole temperature. The method may still further include determining a parameter of the formation based on the second parameter of the NMR distributions of the set of samples.

An NMR based wettability index determination method for CO.sub.2-liquid-solid system for CO2 and liquid phase wettability assessment may comprise acquiring .sup.1H NMR relaxation time measurements, analyzing brine signals for the comparable brine-filled pores from various step, applying a wettability index model constructed with NMR alone and calibrated with another wettability measurement, and applying the wettability index model to interpret wettability of CO2-containing rock system from corresponding NMR measurements.

Apparatus for the measurement of ore in mine ore benches or ore stockpiles is disclosed, the apparatus comprising: a mobile platform, defining a platform zone, wherein the mobile platform is positionable on or above a mine ore bench or stockpile; and at least one magnetic resonance (MR) sensor comprised in the mobile platform. The MR sensor includes a main loop and a drive loop located above the main loop. A magnetic resonance sensor control system is provided and configured to control at least one of: the positioning of the at least one MR sensor relative to the platform zone and/or mine ore bench or ore stockpile; the positioning of elements comprised in the MR sensor relative to each other; electromagnetic suppression characteristics of the at least one MR sensor; and/or sensitivity of the at least one MR sensor as a function of distance of the sensor from the mine ore bench or ore stockpile.

A method of estimating a wettability characteristic of a rock material includes acquiring a plurality of T2 distributions based on nuclear magnetic resonance (NMR) measurements of a rock material under a plurality of fluid saturated rock conditions, constructing a measurement matrix based on the plurality of T2 distributions, and performing non-negative factorization of the measurement matrix to determine feature components. The method also includes reconstructing the plurality of T2 distributions based on the feature components, and extracting a first set of T2 distributions associated with mobile water under a wetting condition and a second set of T2 distributions associated with mobile water under a non-wetting condition based on the feature components, and calculating a wettability index (WI) based on the first extracted set of T2 distributions and the second extracted set of T2 distributions.

A coring tool includes a coring bit to cut and detach a core sample from a subsurface formation formed in a borehole. The coring tool includes a pressure vessel that includes a core chamber to store the core sample at a pressure and a piston positioned adjacent to the core chamber. The pressure vessel includes a chamber adjacent to the piston and a gas reservoir to store a gas that expands as the gas is moved to a surface of the borehole. The pressure vessel includes a valve coupled to an inlet of the chamber and an outlet of the gas reservoir, wherein the gas is to flow into the chamber when the valve is open to move the piston to cause an increase in the pressure of the core chamber.

A porosity model of a core sample obtained from a subterranean formation is determined. The porosity model includes a macroporosity group and a microporosity group. A nuclear magnetic resonance (NMR) measurement is performed to obtain an NMR T.sub.2 distribution of the core sample at 100% water saturation. A desaturation step is performed on the core sample. An NMR measurement is performed for the desaturation step to obtain an NMR T.sub.2 distribution of the core sample. A resistivity index of the subterranean formation is determined at least based on the porosity model and each of the NMR T.sub.2 distributions.

A method of estimating a wettability characteristic of a rock and fluid system includes acquiring a sample of the rock material, performing a first nuclear magnetic resonance (NMR) measurement of the sample when the sample is in a full water saturation condition, and measuring a first T2 distribution, performing a second NMR measurement of the sample when the sample is in a second partial saturation condition, and measuring a second T2 distribution. The method also includes separating a hydrocarbon component of the second T2 distribution from a water component of the second T2 distribution, applying a fluid substitution model to the water component of the second T2 distribution to generate a computed T2 distribution, and calculating a wettability index (WI) based on a difference between the first T2 distribution and the computed T2 distribution.

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.

A method and microfluidic device to perform reservoir simulations using pressure-volume-temperature (“PVT”) analysis of wellbore fluids.