TrackerExpress Resistivity

The TrackerExpress(TM) is a new class of LWD azimuthal resistivity tool that offers both propagation and azimuthal resistivity measurements from a compact sub.

With a sub length of 8ft (~2.4m), the tool permits assembling of a complete M/LWD tool string in shops.

The tool is designed to run with low-speed MWD systems with data telemetry rates on the order of 1 BPS. The tool can be run above either an RSS or a motor.

The TrackerExpress* offers 4 high-accuracy propagation resistivity measurements and 128 azimuthal resistivity measurements, all fully compensated to minimize borehole and other environmental effects. Out of the numerous measurements, the tool sends, via mud pulser or EMWD, a small set of compressed data to surface in real time. On surface, the data is decompressed and then inverted with the proprietary software to produce the key parameters needed for geosteering and well placement, including the distance to bed boundaries and the bed resistivities.

The TrackerExpress™ tool is available in both 4.75” and 6.75” sizes. The nominal temperature and pressure ratings are 150°C and 20,000psi. Higher temperature and pressure ratings of 175°C and 25,000psi are also available.


  • Unique feature of continuous boundary tracking, even in a sliding mode
  • Compact sub length of 8ft (~2.4m), permits assembling of complete M/LWD tool-string in workshop
  • Designed to run with low-speed MWD systems with data telemetry rates around 1 BPS
  • The tool can be run above either an RSS or a motor
  • Option of including Azimuthal Gamma or Pressure sensor


  • Compact sub – Face-to-face 8ft (~2.4m)
  • 4 fully compensated propagation resistivities
  • 128 fully compensated azimuthal resistivities
  • Depth of investigation up to 10ft.
  • Boundary tracking while rotating or sliding
  • Rated at 150°C & 20000psi (175°C & 25000psi option)
  • Applications include: Oil-water contact mapping, Overpressure detection, Reservoir boundary tracking


Tool size4-3/4 in.6-3/4 in.
Hole size range5-7/8 in. to 6-3/4 in.8-3/8 in. to 10-5/8 in.
Max OD5-1/4 in.7 in.
Min ID1-1/4 in.2 in.
Length96 in.*96 in.*
Top connectionCustomer SpecifiedCustomer Specified
Bottom connectionCustomer SpecifiedCustomer Specified
Connection makeup torque10,000 lbf-ft*30,000 lbf-ft*
Max DLS rotating15°/100ft8°/100ft
Max DLS sliding30°/100ft16°/100ft
Max operating pressure20,000 psi / 25,000psi20,000 psi / 25,000psi
Max operating temperature150°C / 175°C150°C / 175°C
Max RPM200200
Max torque>10,000 lbf-ft*>35,000 lbf-ft*
Max WOB50,000 lbf*100,000 lbf*
Max sand content1%1%
Max flow rate~400 gpm~800 gpm
Resistivity range0.2 – 3,000 ohmm
Vertical resolution1.25ft at 1 ohmm
Depth of investigationPropagation resistivity – Up to 10ft, Azimuthal resistivity – Up to 10ft
Azimuthal resistivity sectors16
Azimuthal gamma (option) sectors16

Resistivity Measurement Accuracy

Phase Difference35″400
0.2 – 4
2%4 – 250
5 mmhos
0.2 – 25
2%25 – 3,000
1 mmhos
0.2 – 6
5%6 – 10
7 mmhos
0.2 – 40
5%40 – 200
3 mmhos