Apparatus and method for measuring dielectic permitivity of cylindrical samples
AssigneeSchlumberger Technology Corporation
InventorsMOHAMMED BADRI, REZA TAHERIAN
Life of this patent
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Abstract
An open ended coaxial probe is disclosed that can be used to measure the dielectric properties of solids. According to some embodiments, the probe is specially designed to make good contact with solids having flat or non-flat surfaces. This design relies on forcing a good contact between the solid surface with both the center conductor and outer conductor of the coaxial probe. A method is also described in which the coaxial probe is used to monitor the dielectric permittivity of cylindrical samples such as rock cores drilled from a well. Also described are methods of using the coaxial probe to provide a continuous log of the dielectric permittivity of a rock core.
Claims30
A coaxial-based sensor probe for making dielectric measurements of a solid sample, the probe comprising:
- a central conductor having a tip for contacting a surface of the solid sample, the central conductor defining a longitudinal axis of the probe;
- a dielectric material surrounding at least a portion of the central conductor;
- an outer conductor surrounding at least a portion of the dielectric material, and having a circular cross section in a plane perpendicular to the longitudinal axis along at least a portion of the outer conductor;
- and
- a shaped conductor having a circular cross section in a plane perpendicular to the longitudinal axis along a portion of the shaped conductor and having an edge shape that corresponds to an expected shape of a non-flat surface of the solid sample, wherein the outer conductor and shaped conductor are arranged such that the outer and shaped conductors are centered about the longitudinal axis and are in electrical contact with each other.
A method of making dielectric measurements from a non-flat surface of a solid material using a coaxial sensor probe, the method comprising:
- moving a central conductor and a shaped conductor of a coaxial-based sensor probe into contact with the non-flat surface of the solid material, the shaped conductor having a circular cross section in a plane perpendicular to a longitudinal axis of the central conductor along at least a portion of the shaped conductor, and the shaped conductor having an edge shape that corresponds to the non-flat surface of the solid sample;
- measuring a scattering parameter from an interface between the sensor probe and the sample material;
- and
- deriving one or more values for dielectric permittivity based at least in part on the scattering parameter measurements.
A coaxial-based sensor probe for making dielectric measurements of a solid sample, the probe comprising:
- a central conductor having a tip for contacting a surface of the solid sample, the central conductor defining a longitudinal axis of the probe;
- a dielectric material surrounding at least a portion of the central conductor;
- and
- an outer conductor surrounding at least a portion of the dielectric material, and having a circular cross section in a plane perpendicular to the longitudinal axis along at least a portion of the outer conductor, the outer conductor including an edge shape and position relative to the central conductor tip that corresponds to an expected shape of a non-flat surface of the solid sample such that electrical contact between the central conductor tip and the non-flat surface and electrical contact between the outer conductor and the non-flat surface are suitable for dielectric measurements of the solid sample.
Dependencies are inferred from the claim text.