Downhole NMR processing
First Claim
1. An apparatus for drilling a borehole and determining a parameter of interest of a formation surrounding the borehole, said apparatus comprising:
- (a) a longitudinal member for rotating a drill bit and adapted to be conveyed in the borehole;
(b) formation evaluation sensor on said longitudinal member for making measurements indicative of at least one of (A) a lithology of the formation, and, (B) a fluid content of the formation;
(c) an expert system for determining from said measurements of the formation evaluation sensor at least one of (C) the lithology of the formation, and, (D) the fluid content of the formation.
1 Assignment
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Accused Products
Abstract
An expert system is included in a downhole processor designed to acquire and process NMR data downhole in real time. The downhole processor controls the acquisition of the NMR data based at least in part on instructions transmitted downhole from a surface location and at least in part on evaluation of downhole conditions by the expert system. The downhole conditions include drilling operation conditions (including motion sensors) as well as lithology and fluid content of the formation obtained from other MWD data. The wait time, number of echos, number of repetitions of an echo sequence, interecho time, bandwidth and shape of the tipping and refocusing pulses may be dynamically changed. Data processing is a combination of standard evaluation techniques. Selected data and diagnostics are transmitted uphole. The expert system may be implemented as a two stage neural net. The first stage does the formation evaluation and the second stage controls the NMR pulse sequence.
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Citations
27 Claims
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1. An apparatus for drilling a borehole and determining a parameter of interest of a formation surrounding the borehole, said apparatus comprising:
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(a) a longitudinal member for rotating a drill bit and adapted to be conveyed in the borehole; (b) formation evaluation sensor on said longitudinal member for making measurements indicative of at least one of (A) a lithology of the formation, and, (B) a fluid content of the formation; (c) an expert system for determining from said measurements of the formation evaluation sensor at least one of (C) the lithology of the formation, and, (D) the fluid content of the formation.
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2. An apparatus for determining a parameter of interest of a formation surrounding a borehole, said apparatus comprising:
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(a) a nuclear magnetic resonance (NMR) sensor producing a pulsed RF field for obtaining first measurements indicative of the parameter of interest of the formation, the RF field characterized by a plurality of parameters; and (c) a processor including an expert system for controlling at least one parameter of the pulsed RF field. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of determining a parameter of interest of an earth formation comprising:
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(a) conveying a logging assembly into a borehole in the earth formation; (b) using a nuclear magnetic resonance (NMR) sensor on the logging assembly and producing a pulsed RF field for obtaining first measurements indicative of the parameter of interest of the formation, the RF field characterized by a plurality of parameters; and (c) using a processor including an expert system for determining a lithology of the formation and selecting at least one parameter of the pulsed RF field based at least in part on the determined lithology. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification