Method and apparatus to train telemetry system for optimal communications with downhole equipment
US5473321A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1994 |
| Grant date | Dec 5, 1995 |
| Priority date | — |
| Expiry date | Mar 15, 2014 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A telemetry system employs a periodic pseudorandom training sequence to effectively initialize an adaptive digital FIR filter-equalizer for optimal communications between a surface modem and downhole measuring equipment, without requiring any changes to the normal logging configuration or any special operator intervention. In a "training mode", an electronic source in a downhole sonde transmits a predetermined training sequence to a surface modem via a cable. The source preferably transmits the training sequence continuously until the surface modem has acclimated itself to the characteristics of the multiconductor cable by adaptively configuring the filter-equalizer, thereby enabling the surface modem to accurately interpret data received from the sonde despite attenuation, noise, or other distortion on the cable. The filter-equalizer adjusts itself in response to an error signal generated by comparing the filter-equalizer's output with a similar training sequence provided by a training generator. After the surface modem is trained, the system operates in an "operational mode," in which the sonde transmits data corresponding to downhole measurements, and the filter-equalizer's erro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.