Electromagnetic surveying for resistive or conductive bodies
US8099239B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2005 |
| Grant date | Jan 17, 2012 |
| Priority date | — |
| Expiry date | May 6, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A90/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of analyzing electromagnetic survey data from an area of seafloor (6) that is thought or known to contain a conductive or resistive body, such as a subterranean hydrocarbon reservoir (12), is described. The method includes providing electric field data and magnetic field data, for example magnetic flux density, obtained by at least one receiver (25) from a horizontal electric dipole (HED) transmitter (22) and determining a vertical gradient in the electric field data. The vertical gradient in the electric field data and the magnetic field data are then combined to generate combined response data. The combined response data is compared with background data specific to the area being surveyed to obtain difference data sensitive to the presence of a subterranean hydrocarbon reservoir. Because the combined response data are relatively insensitive to the transverse electric (TE) mode component of the transmitted signal, the method allows hydrocarbon reservoirs to be detected in shallow water where the TE mode component interacting with the air would otherwise dominate. Furthermore, because there is no mixing between the TE and transverse magnetic (TM) modes in the combined resp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.