Formation evaluation utilizing dual wait time nuclear magnetic resonance
AssigneeBaker Hughes, A Ge Company, LLC
InventorsRadu Coman, Holger Tietjen, Holger F. Thern, Martin Blanz
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Abstract
A system for measuring a property of fluid in an earth formation includes a downhole tool disposed in a borehole and configured to be movable within the borehole and a nuclear magnetic resonance (NMR) measurement device including a transmitter configured to emit at least two pulse trains of magnetic energy into the earth formation and a detector configured to detect a long-TW echo train and a short-TW echo train resulting from the at least two pulse trains. The system also includes a processor configured to combine the information from the at least two pulse trains and a rate of penetration of the downhole tool to form a measurement of the property.
Claims16
A system for measuring a property of an earth formation, the system comprising:
- a downhole tool disposed in a borehole and configured to be movable within the borehole;
- a nuclear magnetic resonance (NMR) measurement device disposed in said downhole tool including a transmitter configured to emit a first pulse train with a long wait time (TWL ) and a second pulse train with a short wait time (TWS ) that is different than TWL into the earth formation and a detector configured to detect a TWL echo train and a TWS echo train resulting from the first and second pulse trains, respectively;
- and
- a processor configured to combine the information from the TWL and TWS echo trains and a speed of axial motion of the downhole tool to determine a T1 relaxation time and to perform a computation of the property of the earth formation based on the determined T1 relaxation time.
A method for measuring a property of an earth formation, the method comprising:
- disposing a downhole tool in a borehole;
- emitting with a nuclear magnetic resonance (NMR) measurement device disposed in said downhole tool a first pulse train with a long wait time (TWL) and a second pulse train with a short wait time (TWS) that is different than TWL into the earth formation;
- detecting with a detector on the NMR device a TWL echo train and a TWS echo train resulting from the first and second pulse trains, respectively;
- and
- combining with a processor the information from the TWL and TWS echo trains and a speed of axial motion of the downhole tool to determine a T1 relaxation time and perform a computation of the property of the earth formation based on the determined T1 relaxation time.
Dependencies are inferred from the claim text.