Capacitance Array Tool


Identifies cross-sectional fluid phases in high-deviation and horizontal wells based on the difference in dielectric constants of oil, gas, and water


  • Water-holdup measurement in deviated or horizontal wellbores
  • Identification and mapping of multiphase fluid segregation

Features and Benefits

  • Cross-sectional water-holdup profiling provides a radial fluid-phase measurement to build a more complete fluid profile in deviated wells.
  • Memory and surface readout operations ensure that the toolstring can be run on a variety of conveyance platforms, which enables deployment using the most cost-effective method.
  • The capacitance array tool (CAT) can operate simultaneously with Sondex™ Ultrawire™ tools that measure other aspects of the flow stream, such as fluid makeup, to ensure that all measurements are obtained at the same moment and to enable measurements of various casings.
  • Tool Description

The CAT identifies fluid phases in high-deviation and horizontal wells based on the difference in the dielectric constants of oil, gas, and water. Run centralized in the wellbore, the CAT is fully combinable with other production logging tools to provide a comprehensive production well profile.

The CAT uses an array of 12 miniature sensors mounted on the inside of a set of collapsible bow-springs to measure the capacitance of the surrounding fluid close to the well casing. All 12 values are simultaneously transmitted to the surface or into a memory section. Taking measurements in a single plane across the diameter of the wellbore, rather than along it, results in an accurate crosssectional plot of fluid phases. Combined with the Weatherford spinner array tool (SAT) and the resistance array tool (RAT), the CAT enables quantitative estimates of the volumetric flow rate for each phase. MAPview software allows for threedimensional phase profiling and viewing.