Electromagnetic Telemetry

The Enteq Twin EM telemetry system provides high-speed electromagnetic uphole data transmission.

The system can be used in EM standalone mode where mud pulse telemetry is not possible.  The system is designed to be run in Twin combination with a pulser to provide added data security and increase real-time data bandwidth.

Advantages

  • Improved overall reliability, with a combined mud pulse and EM telemetry system
  • Twice as fast as previous generation alternative EM systems at same carrier frequency delivering faster updates
  • Twin EM gives the ability to slide out of casing shoe
  • EM enables drilling in discontinuous borehole fluid column
  • Drill in highly resistive formations
  • Faster MWD/LWD data-point update rates
  • Built-in redundancy – no switch over needed between systems if one system encounters problems
  • Can be run as stand-alone EM system if the operating environment dictates
  • Ability to add an EM repeater system to extend EM transmission range

Features

  • 20W output equivalent to 60W competitor output optimising battery length without compromising operational efficiency
  • Data rate up to 10 BPS. 10 x standard MWD mud pulse
  • Fully retrievable
  • 2-10 Hz adjustable carrier frequency
  • Transmit 4 global parameters: Gamma (including focused), Toolface, three generic variables including shock, vibration and resistivity
  • Updates at 15 second intervals compared to 120 seconds for mud pulse
  • Constant current mode enables automatic lithology compensation
  • Power efficient mode for signal transmission through formation (Example:10 ohm.m formation)
  • Standard power mode (120 hours/battery)
  • Power saving mode (240 hours/battery)
  • 75% less power than other systems
  • Ultra low-noise receiver technology – capable of detecting low/weak signal under 20nV amplitude meaning deeper operations (TVD in excess of 2500m and MD in excess of 4000m)
  • Continuous wave (AC) transmission model

Specifications

Transmission ModeContinuous Wave
Wireline RetrievabilityFully retrievable
Typical Operating Depth (no repeater)10,000 ft (3,000 m)
Maximum depthOver 12,000 ft (3600m)
Data Rate10 bps
Operating Pulse Width0.4-0.8 seconds
Battery2 x standard Lithium batteries
Typical Battery LifeOver 200 hours per battery
Maximum Power Draw20W (60W equivalent)
Gap Sub OD available8”, 61/2”, 43/4”, 31/2”
Tool ProgrammingFully surface programmable
Downlink Pump-controlEM power and frequency downhole-programmable
Operating Temperature175 C (350F)
Maximum Pressure20,000 psi (137.9 MPa)
Shock1,000g
Vibration30-500Hz 20g all axes