Electromagnetic Repeater

The most efficient way to extend the depth capability of downhole EM telemetry.

The EM Repeater can restore full EM telemetry strength even when signal to noise ratio on surface from the downhole transmitter goes as low as 2-3.  Recovered signal strength gain with Twin EM repeater can be over 10,000, effectively doubling EM operational range.

With downhole power proportional to the square of EM output, the EM repeater is an excellent alternative to simply increasing the power of a single downhole transmitter, which would require megawatts of power and is practically impossible.

The EM Repeater delivers a significantly more efficient power gain than a mud turbine generator.

Advantages

  • Significantly reduced gap sub current leakage when drilling with highly conductive brine mud
  • Covers wide range of formation resistivities, including highly resistive rock formations
  • Constant current automatic lithology compensation – power conservation during operation and signal reliably in challenging formations

Features

  • Plug and play compatible with Twin EM
  • Advanced embedded efficient decoding – Fast data rate up to 10 bit per second
  • Power economy: high voltage output with typical 200 hours per battery
  • Effectively doubles maximum Twin EM depth, with signal gain over 10,000
  • Ultra low-noise downhole receiver technology (intrinsic noise under 0.2μV)
  • Mechanically robust: no moving mechanical parts
  • Surface-programmable
  • High MTBF 3000+ hrs 100

Specifications

Operating PrincipleMid-sting decoding and retransmission to surface
Transmission ModeContinuous Wave
Placement depthMid-string, when Twin signal to noise ratio approaches 2-3
System Operating Depth after Placement (varies depending on formation)Up to 32,000 ft (10 km)
Carrier Frequency5 Hz standard, 2-10 Hz programmable
Carrier frequency : Data rate ratio1:1
Effective Data Throughput2-10 bps programmable
RetrievabilityNon-retrievable
Current Output6A
Voltage Output to FormationUp to 30V
Full Load Energy EfficiencyOver 90%
Battery1x or 2x standard 29V, 29 A-h lithium batteries (user provided)
Battery Life (varies depending on formation)Up to 580 hours/battery pack
Gap Sub OD available8”, 6 ½”, 4 ¾”, 3 ½”
Flow SwitchVibration
Tool ProgrammingSurface programmable carrier frequency
Operating Temperature175C (350F)
Maximum Pressure1,000g 0.5ms
Vibration30-500Hz 20g all axes