Patent ID: 8928324
Filing Date: 2015-01-06
Classification: G01V,Y02A

Abstract:
1. A method of electromagnetic geophysical surveying comprising: disposing a first and a second source electrode in a body of water, forming a first electromagnetic source, wherein the first source electrode is located on a first source cable and the second source electrode is located on a different second source cable; disposing a third source electrode in the body of water, wherein the third source electrode is located on the first source cable, and the first and third source electrodes form a second electromagnetic source; disposing a first and a second receiver electrode in the body of water; actuating the first electromagnetic source to impart a first electromagnetic field to a formation below the body of water, the actuating the first electromagnetic source comprises imparting a first time-varying current to the first and second source electrodes; actuating the second electromagnetic source to impart a second electromagnetic field to the formation below the body of water, the actuating the second electromagnetic source comprises imparting a second time-varying current to the first and third source electrodes; the first and second time-varying currents differ in at least one of: amplitude, frequency, phase, switching sequence, or any combination thereof; detecting a responsive electromagnetic field by measuring a potential difference between the first and the second receiver electrodes, wherein: