Multi-sensor system for airborne geophysical prospecting and method

Patent metadata

Field	Value
Publication number	US-2016178782-A1
Application number	US-201514966059-A
Country	US
Kind code	A1
Filing date	Dec 11, 2015
Priority date	Dec 17, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

First claim

What is claimed is:

1 . A multi-sensor electromagnetic (EM) system for measuring EM signals, the multi-sensor EM system comprising:
a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

2 . The system of claim 1 , wherein the frame is made of hollow tubes that host coils of the transmitter device, receiver device and the gradient sensor device.

3 . The system of claim 1 , wherein the transmitter device includes three transmitter coils perpendicular to each other, the receiver device includes three receiver coils perpendicular to each other, and the gradient sensor device includes three gradient coils perpendicular to each other.

4 . The system of claim 3 , wherein each gradient coil includes two parallel coils that sandwich a corresponding transmitter coil.

5 . The system of claim 4 , wherein the two parallel coils are electrically connected to each other so that currents flowing through the two coils have opposite directions.

6 . The system of claim 3 , wherein a receiver coil is a null-coupled coil.

7 . The system of claim 6 , wherein the null-coupled coil includes two concentric coils located in a same plane and current flowing through the two concentric coils flow in opposite directions.

8 . The system of claim 7 , wherein the two concentric coils are located in a same plane with a corresponding transmitter coil.

9 . The system of claim 8 , wherein the two concentric coils are concentric with the transmitter coil.

10 . An electromagnetic (EM) surveying system for measuring EM signals, the EM surveying system comprising:
an airborne carrier configured to fly over ground; a multi-sensor EM system configured to generate a primary EM field and to record a secondary EM field generated by the earth as a response to the primary EM field; and a towing system connecting the airborne carrier to the multi-sensor EM system wherein the multi-sensor EM system is also configured to measure a gradient of the secondary EM field.

11 . The system of claim 10 , wherein the multi-sensor EM system comprises:
a frame; a transmitter device attached to the frame and configured to generate the primary EM field; a receiver device attached to the frame and configured to record the secondary EM field; and a gradient sensor device attached to the frame and configured to record the gradient of the secondary EM field.

12 . The system of claim 10 , wherein the carrier is a hybrid air vehicle.

13 . The system of claim 10 , wherein the transmitter device includes three transmitter coils perpendicular to each other, the receiver device includes three receiver coils perpendicular to each other, and the gradient sensor device includes three gradient coils perpendicular to each other.

14 . The system of claim 13 , wherein each gradient coil includes two parallel coils that sandwich a corresponding transmitter coil.

15 . The system of claim 14 , wherein the two parallel coils are electrically connected to each other so that currents flowing through the two coils have opposite directions.

16 . The system of claim 13 , wherein a receiver coil is a null-coupled coil and the null-coupled coil includes two concentric coils located in a same plane and current flowing through the two concentric coils flow in opposite directions, and wherein the two concentric coils are located in a same plane with a corresponding transmitter coil and the two concentric coils are concentric with the transmitter coil.

17 . A method for recording electromagnetic (EM) signals during an airborne EM survey, the method comprising:
flying a multi-sensor EM system; generating a primary EM field with a transmitter device attached to a frame of the multi-sensor EM system; recording, with a receiver device attached to the frame, a secondary EM field generated by the earth after being excited by the primary EM field; and recording, with a gradient sensor device attached to the frame, a gradient of the secondary EM field.

18 . The method of claim 17 , wherein the transmitter device includes three transmitter coils perpendicular to each other, the receiver device includes three receiver coils perpendicular to each other, and the gradient sensor device includes three gradient coils perpendicular to each other.

19 . The method of claim 18 , wherein each gradient coil includes two parallel coils that sandwich a corresponding transmitter coil.

20 . The method of claim 19 , wherein the two parallel coils are electrically connected to each other so that currents flowing through the two coils have opposite directions.

Assignees

• Cgg Services Sa

Inventors

• Miles Philip

Classifications

• G01V3/17

  operating with electromagnetic waves {(operating with millimetre waves G01V8/005)} · CPC title

• G01V3/165 Primary

  operating with magnetic or electric fields produced or modified by the object or by the detecting device (with electromagnetic waves G01V3/17) · CPC title

• G01V3/16

  specially adapted for use from aircraft (G01V3/165 - G01V3/175 take precedence) · CPC title