Schlumberger Technology Corporation

Paul L Baker

William E Kenyon

Pabitra N Sen

Jayanth R Banavar

Well logging techniques are set forth for obtaining improved measurements of formation dielectric permittivity, conductivity, and water-filled porosity. The effects of dielectric and conductivity frequency dispersion are considered and utilized. In a disclosed embodiment, an estimated low frequency conductivity of a formation surrounding a borehole is determined using the following steps: deriving a measured value of formation high frequency conductivity from a logging device which traversed the borehole; determining a formation conductivity dispersion ratio as a function of the measured conductivity; and determining an estimated low frequency conductivity from the measured value of high frequency conductivity and the dispersion ratio.

Method for determining low frequency conductivity of subsurface

Well logging techniques are disclosed which use and/or measure formation textural parameters. A disclosed formation textural model is bimodal in nature, and includes fractions of spherical grains and of platey grains having a single aspect ratio. This model is used in obtaining improved well logging recordings.

Method and apparatus for obtaining properties of subsurface formations

Well logging techniques are set forth for obtaining improved measurements of formation dielectric permittivity, conductivity, and water-filled porosity. The effects of dielectric and conductivity frequency dispersion are considered and utilized. In a disclosed embodiment, a corrected dielectric permittivity of a formation surrounding a borehole is determined using the following steps: deriving a measured value of formation dielectric permittivity from a logging device which traversed the borehole; deriving a measured value of formation conductivity from a logging device which traversed the borehole; determining a formation dielectric permittivity dispersion value as a function of the measured conductivity; and determining a corrected formation dielectric permittivity from the measured value of dielectric permittivity and the dispersion value.

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Ridgefield, CT, United States of America

Paul L Baker