Nuclear magnetic resonance detection of geologic structures
AssigneeNumar Corporation
InventorsGeorge R. Coates, Melvin N. Miller, John C. Bouton
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Abstract
An improved system for using nuclear magnetic resonance techniques to obtain information relating to geologic structures. The system of the present invention employs a variable sampling window which increases sampling efficiency by allowing the system to optimize the sampling interval, thereby maximizing the amount of data which can be obtained in a series of data samples.
Claims9
A method for determining the optimum sampling interval for measurement of parameters related to the composition of a geologic structure, comprising the steps of:
- (a) imparting a polarizing magnetic field to a geologic structure for a predetermined period of time;
- (b) repeatedly exciting the nuclei of a population of particles in said geologic structure with an RF field;
- (c) measuring repeatedly during a first time interval nuclear magnetic resonance echo signals of said population of particles in said geologic structure so as to acquire a chain of echo signals;
- and
- (d) determining from said chain of echo signals an optimum sampling interval for obtaining a plurality of subsequent data measurements relating to said geologic structure.
A method for determining the optimum sampling interval for measurement of parameters related to the composition of geologic structure, comprising the steps of:
- (a) imparting a polarizing magnetic field to a geologic structure for a predetermined period of time;
- (b) repeatedly exciting the nuclei of a population of particles in said geologic structure with an RF field;
- (c) measuring repeatedly during a first time interval echo signals of said population of particles in said geologic structure so as to acquire a chain of echo signals;
- (d) performing a regression analysis of said chain of echo signals to determine the relaxation characteristics of said geologic structure;
- (e) using said regression analysis to determine an optimum sampling interval for obtaining subsequent nuclear magnetic resonance measurements of said geologic structure;
- and
- (f) obtaining a plurality of subsequent data measurements relating to said geologic structure, said subsequent data measurements comprising a plurality of chains of echo signals obtained using said optimum sampling interval.
An apparatus for determining the optimum sampling interval for measurement of parameters related to the composition of a geologic structure, comprising:
- means for imparting a polarizing magnetic field to a geologic structure for a predetermined period of time;
- means for repeatedly exciting the nuclei of a population of particles in said geologic structure with an RF field;
- means for measuring repeatedly during a first time interval echo signals of said population of particles in said geologic structure so as to acquire a chain of echo signals;
- and
- means for determining from said chain of echo signals an optimum sampling interval for obtaining data relating to said geologic structure.
Dependencies are inferred from the claim text.