SP noise cancellation technique
US5229765A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 8, 1991 |
| Grant date | Jul 20, 1993 |
| Priority date | — |
| Expiry date | May 8, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/265
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An adaptive transversal filter is incorporated with an SP conductor extending through a logging cable to the surface from an SP electrode supported on a sonde. This logging cable is operated in a noisy environment and there is the risk of noise on the logging cable obscuring the SP signal. The SP signal is obtained at the surface and is passed through a filter system. One input to the filter system utilizes an AC ammeter connected to the AC power source for the logging cable and that signal is input to a multi-stage adaptive transversal filter. The filter output is a recreation of the noise imposed on the SP conductor and when summed with the SP output signal, provides a signal which is substantially noise free.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.