Simultaneous Array Induction Tool


Provides high-resolution formation resistivity (Rt) measurements to determine hydrocarbon saturation



  • Determining true formation resistivity (Rt)
  • Determining water saturation (Sw)
  • Identifying moveable hydrocarbons
  • Creating formation invasion profiles
  • Identifying fluid contacts
  • Enabling thin-bed analysis
  • Providing well-to-well correlation

Features and Benefits

  • The multifrequency, multicoil array provides accurate and stable responses at multiple depths of investigation (DOI).
  • Advanced array focusing enhances radial and vertical resolution at each DOI, which improves Rt determination and simplifies interpretation.
  • Integrated mud resistivity and temperature sensors compensate for environmental conditions in real time, which enables the tool to provide accurate responses.

Tool Description

The simultaneous array induction (SAI) tool provides accurate, high-resolution resistivity measurements. These measurements are vital for determining true formation resistivity (Rt) and characterizing invasion in formation evaluation.

The SAI tool provides data acquired at multiple frequencies from multiple coils to eliminate skin effect, to improve borehole corrections, and to optimize the real-time processing of the array induction data. The processing uses a software focusing method to provide fixed DOI resistivity curves at 10, 20, 30, 60, and 90 in. The algorithm determines borehole and formation responses to produce radial curves at vertical resolutions of 1, 2, and 4 ft.


The SAI tool can be combined with other Weatherford wireline services for a complete formation evaluation solution. The tool can also be combined with the Weatherford dual laterolog tool to provide accurate induction-based resistivity measurements in high contrast (Rr/Rm) environments.