Nuclear magnetic resonance (NMR) gas isotherm techniques to evaluate wettability of porous media, such as hydrocarbon reservoir rock, can include constructing a NMR gas isotherm curve for a porous media sample gas adsorption under various pressures. A hydrophobic or hydrophilic nature of the porous media sample can be determined using the NMR gas isotherm curves. A wettability of the porous media sample can be determined based on the NMR gas isotherm curve. The wettability can be determined for porous media samples with different pore sizes. In the case of reservoir rock samples, the determined wettability can be used, among other things, to model the hydrocarbon reservoir that includes such rock samples, to simulate fluid flow through such reservoirs, or to model enhanced hydrocarbon recovery from such reservoirs.

A pressure sensor includes a chamber comprising a conductive portion and a deformable portion coupled to the conductive portion and susceptible to deformation in response to a pressure differential between an interior of the chamber and an exterior of the chamber; at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element disposed proximate to the at least one coil and to the conductive portion of the chamber and configured to generate a magnetic field signal in response to a reflected magnetic field generated by the at least one coil and reflected by the conductive portion; and a circuit coupled to the at least one magnetic field sensing element to generate an output signal of the pressure sensor indicative of the pressure differential between the interior of the chamber and the exterior of the chamber in response to the magnetic field signal.

Systems and methods for testing properties of a test sample with a tri-axial nuclear magnetic resonance include a tri-axial load frame encasing a tri-axial load cell having a tri-axial sample holder and a piston assembly. A radial space surrounds the tri-axial sample holder. The tri-axial load frame further encases at least one end cap operable to contact the tri-axial load cell, and a nuclear magnetic resonance instrument. An axial pressure line is in fluid communication with the piston assembly, a confining pressure line is in fluid communication with the radial space, and a pore pressure line in fluid communication with the test sample. The axial pressure line, the confining pressure line, and the pore pressure line are independent and separate fluid flow paths.

Pressure coring where the core apparatus drills the core sample and seals the core sample at its native downhole pressure (e.g., several thousand psi) may be expanded to include nuclear magnetic resonance (NMR) imaging components to produce a pressurized NMR core holder that allows for NMR imaging of the core samples having been maintained in a downhole fluid saturation state. NMR imaging performed may include 1H and also 19F imaging depending on the chamber fluid used in the pressurized NMR core holder.

A method and system are described for imaging core samples associated with a subsurface region. The imaging results may be used to create or update a subsurface model and using the subsurface model and/or imaging results in hydrocarbon operations. The imaging techniques may include NMR imaging and CT imaging. Further, the imaging techniques may also include exposing the core sample to the imaging gas.

A method and system are described for imaging core samples associated with a subsurface region. The imaging results may be used to create or update a subsurface model and using the subsurface model and/or imaging results in hydrocarbon operations. The imaging techniques may include NMR imaging and CT imaging. Further, the imaging techniques may also include exposing the core sample to the imaging gas.

Core samples may been collected in a subterranean formation, preserved downhole in a pressurized nuclear magnetic resonance (NMR) core holder (1) comprising components for NMR imaging and (2) capable of maintaining the core samples at downhole fluid saturation state. For example, a pressurized NMR core holder may comprise a housing capable of containing downhole fluid pressures; a coil holder lining an inside of the housing and defining a core chamber; and one or more NMR coils maintained in a longitudinal position along the housing by the coil holder. Further, a system for performing the NMR imaging may comprise: a holder that maintains a pressurized NMR core holder in a desired position; and one or more magnets that are longitudinally movable along the pressurized NMR core holder.

The invention provides a tri-axial nuclear magnetic resonance apparatus for testing of petro-physical properties and gathering of geo-mechanical information and methods of using the same. The tri-axial nuclear magnetic resonance apparatus includes a tri-axial load frame encasing a tri-axial load cell that includes a tri-axial sample holder, at least one electrical sensor, at least one acoustic sensor, and a nuclear magnetic resonance instrument.

A nuclear magnetic resonance (NMR) sample analyzer has a plurality of NMR units arrayed in a predetermined relationship to each other. Each of the NMR units includes a sample chamber having a sensitive volume for containing a sample to be analyzed; a radio frequency (RF) transmitting and receiving device proximal the sample chamber; and a magnet surrounding the RF transmitting and receiving device and sample chamber for generating a substantially uniform magnetic field within the sensitive volume and substantially no magnetic field beyond an outside wall of the magnet.

The NMR analysis method for analyzing a solid sample positioned in a sample-holder (21) includes generation of a plurality of high-pressure gaseous flows (2, 3, 4) from at least one first source (1) of a high-pressure gas; cooling of the gaseous flows (2, 3, 4) in at least one heat exchanger (12) from a coolant gas (15) originating from at least one second source (11) of gas; and rotation of the sample-holder (21) by a first cooled high-pressure gaseous flow (2) and cooling of the sample-holder by a second cooled high-pressure gaseous flow (3).