Apparatus and method for determining earth's near-surface properties with on-time measurements from airborne time-domain electromagnetic data
AssigneeCgg Services SAS
InventorsAdam Smiarowski, Greg Hodges
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Abstract
A device and method for calculating electrical properties of a surveyed underground formation. The method includes selecting a waveform having multiple current transition rates; placing a time-domain electromagnetic (TEM) system above the underground formation while generating with a transmitter a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, due to the waveform; and recording with a receiver magnetic related data generated by the earth as a result of the transient primary magnetic field. The receiver records the magnetic related data during the on-time period using plural on-time gates sampling.
Claims20
A method for calculating electrical properties of a surveyed underground formation, the method comprising:
- selecting a waveform having multiple current transition rates;
- placing a time-domain electromagnetic (TEM) system above the underground formation while generating with a transmitter a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, due to the waveform;
- and
- recording with a receiver magnetic related data generated by the earth as a result of the transient primary magnetic field,
- wherein the receiver records the magnetic related data during the on-time period using plural on-time gates sampling.
A time-domain electromagnetic (TEM) system for calculating electrical properties of a surveyed underground formation, the TEM system comprising:
- a controller for receiving a waveform having multiple current transition rates;
- a transmitter for generating a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, when the waveform is applied to the transmitter;
- and
- a receiver for recording magnetic related data generated by the earth as a result of the transient primary magnetic field,
- wherein the receiver records the magnetic related data during the on-time period using plural on-time gates sampling.
A non-transitory computer readable medium including computer executable instructions, wherein the instructions, when executed by a processor, implement instructions for calculating electrical properties of a surveyed underground formation, the instructions comprising:
- selecting a waveform having multiple current transition rates;
- instructing a time-domain electromagnetic (TEM) system to generate, with a transmitter, a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, due to the waveform;
- and
- recording with a receiver magnetic related data generated by the earth as a result of the transient primary magnetic field,
- wherein the receiver records the magnetic related data during the on-time period using plural on-time gates sampling.
Dependencies are inferred from the claim text.