Wellsite System and Method for Multiple Carrier Frequency, Half Duplex Cable Telemetry

A system for multiple carrier frequency, half duplex cable telemetry for a wellsite, comprising:

• a surface modem that generates one or more downlink messages in a first propagation mode;
• one or more downhole tools that obtain measurements relating to at least one of borehole characteristics and formation characteristics, the one or more downhole tools coupled by a toolbus to a downhole modem, the downhole modem generating one or more uplink messages in the first propagation mode and in a second propagation mode;
• a cable electrically coupling the surface modem and the downhole modem;
• wherein the downlink and uplink messages are transmitted over the cable sequentially in a plurality of time periods across a single frequency bandwidth, each of the downlink and uplink messages is separated from a most subsequently transmitted one of the downlink and uplink messages by a quiet time sample during which no message is transmitted.

A system for multiple carrier frequency, half duplex cable telemetry for a wellsite, comprising:

• a surface acquisition unit operatively coupling to a surface modem that generates one or more downlink messages in a first propagation mode;
• a downhole modem that generates one or more uplink messages in the first propagation mode and in a second propagation mode;
• a downhole toolstring comprising one or more downhole sensing tools that obtain measurements relating to at least one of borehole characteristics and formation characteristics, the downhole toolstring operatively coupled to the downhole modem via a toolbus;
• a cable electrically coupling the surface modem and the downhole modem;
• wherein the downlink and uplink messages are transmitted sequentially in a plurality of time periods across a single frequency bandwidth, each of the downlink and uplink messages is separated from a most subsequently transmitted one of the downlink and uplink messages by a quiet time sample during which no message is transmitted.