Compact Dual Laterolog Tool


Providing accurate formation resistivity in any wellbore geometry


  • Determining formation resistivity in conductive-mud environments
  • Determining water saturation (Sw)
  • Providing well-to-well correlation
  • Identifying moveable fluids
  • Identifying fluid contacts
  • Creating an invasion profile to indicate permeability, when used with the flushed-zone resistivity (Rxo) microresistivity (MMR) tool

Features and Benefits

  • The arrangement of the electrodes on the Compact dual laterolog (MDL) tool detects the Groningen effect for quality control to provide accurate, real-time, deep-resistivity readings.
  • The MDL can be run in combination with the microlog (MML) pad or the microlaterolog (MMR) pad to obtain an independent, shallower measurement for improved accuracy in determining Rxo and Rt in complex invasion profiles.
  • Data from the MMR or the shallow-focused electric (MFE) tool can be used to significantly enhance the vertical resolution of the MDL to less than 1 ft (0.3 m) for improved thin-bed analysis and reserve estimates.
  • The small diameter of the MDL tool facilitates deployment in wireline or memory mode to mitigate the risk of bridging events and to reduce nonproductive time.
  • The MDL is fully combinable with our Compact array induction (MAI) tool to provide a unique invasion profiling.

Tool Description

The Weatherford Compact™ dual laterolog (MDL) tool is the resistivity tool of choice in wells drilled in high-contrast, true formation resistivities (Rt)/mud resistivities (Rm) environments. The MDL tool provides individually optimized deep- and shallow-penetration curves that share a common 2-ft (0.6-m) vertical resolution. The Groningen curve is used with the deep measurement to detect anomalous responses as the tool approaches nonconductive formations, such as salt caps. Optimized-electrode geometry and digital-measurement sequence control give the tool excellent environmental performance over a wide range of Rm Rm and hole sizes and virtually eliminate electrode-polarization effects.

The voltage reference and simultaneous SP electrodes are incorporated into a stiff bridle at the top of the toolstring to optimize reliability. The cableless logging variant enables running the MDL without a wireline. The MDL tool is normally run with the microlaterolog (MMR) or microlog (MML) tool to determine the invadedzone resistivity.