Halliburton's proven DLL™ dual laterolog service provides a reliable means of measuring formation resistivity in conductive borehole fluids and/or where large contrasts exist between the formation and mud resistivities. The DLL service operates by focusing currents into the formation to produce a deep resistivity measurement (LLd) and a shallow resistivity measurement (LLs). The MSFL™ micro- spherically focused log is usually run in combination to provide a third shallow resistivity measurement. Together, these three measurements provide the resistivity profile around the borehole and permit the computation of Rt in

presence of invasion.

 Applications

• Provides accurate, high resolution shallow (LLs) and deep (LLd) resistivity measurements in high Rt/Rm conditions (>100) or when formation resistivity exceeds the limits for conventional induction tools (> 2,000 ohm-m)

• Quantitative assessment of Sw

• When run with the MSFL log, provides estimates of Rt, Rxo, and diameter of invasion

• Quantitative assessment of moveable water saturations (Sxo) and moveable hydrocarbon volumes

• Acquires improved formation resistivity measurements in saline borehole fluids and in high Rt/Rm (>100) contrast logging conditions or when formation resistivity exceeds the limits of induction tools (>2000 ohm-m)

• Provides MSFL measurements to help delineate thin beds and provide estimates of Rxo

• Offers qualitative indication of permeable zones and estimating invasion diameters (when run with the MSFL tool)

Features

• Rugged sonde construction and state-of-the-art electronics provide for accurate measurements of formation resistivity up to 40,000 ohm-m

• Dual electrode arrays and an automatic current-focusing technique

• The fundamental vertical resolution is 24 for both measurements which facilitates reservoir description of thinly bedded formations