Dual-Sensor Free-Point System and Motorized Anchors


Positive anchoring and dual sensors make identifying the deepest and free section of pipe a single and


  • Vertical and horizontal free-point pipe-recovery applications with restrictions as small as 1.625 in. (41.28 mm)
  • Free-point measurements in internal wellbore diameters ranging from 2.0 to 7.0 in. (50.8 to 177.8 mm)

Features and Benefits

  • A short toolstring makes the system practical for vertical and highly deviated wells.
  • The anchors easily centralize and set in vertical or horizontal wells for accurate measurement, regardless of well orientation.
  • The dual-sensor free-point (DSFP) system can be run with a string shot, enabling completion of free-point and back-off operations in a single run.
  • Separate sensors for independent and simultaneous torque and stretch measurements provide a high degree of accuracy in reduced time.
  • Three knife sets cover an ID range of 2.0 to 7.0 in. (50.8 to 177.8 mm), giving the system a high degree of versatility in the field.
  • Motorized anchors set or retract quickly, which provides quick setup for measurement and rapid extraction afterward.

Tool Description

The Weatherford dual-sensor free-point (DSFP) system is a wireline-deployed free-point locator tool with motorized anchors. It is used for pipe-recovery applications that require the precise determination of the stuck point. DC electric motors operate the anchors, and a positive-voltage telemetry pulse opens and closes the anchors.

After it is anchored in the wellbore, the DSFP system is reset for measurement. The tool operator pulls on the wireline a minimal distance and then relaxes the wireline, allowing an additional amount of cable to minimize measurement errors caused by wireline drag. After reset, the DSFP tool can measure pipe stretch and torque independently. Measured data is transmitted to surface equipment by a pulse-width-modulated (PWM) communication scheme.