Saturday, February 4, 2012

Net pay determination in laminated sediments

The FMI tool is the preferred approach for determining net pay in the laminated sediments typical of fluvial and turbidite depositional environments.The method for obtaining an accurate sand count is to compute an averageresistivity curve from the FMI measurements and apply a cutoff that distinguishes sand from shale.
Laminations as thin as 0.2 in. can be resolved. Sections with laminations thinner than this intrinsic resolution
are analyzed by calibrating FMI lithofacies with the sand count from core. The resulting sand-shale curve can be analyzed for the bed-thickness distribution and used to derive mappable parameters.
In highly laminated sediments, the FMI log clearly shows the net pay zones that can contribute to production.

Wednesday, February 1, 2012

Characterization of rock structure From FMI Logs

FMI images provide critical information if the rock structure and sedimentary features are significant determinants of formation productivity. The figure below shows paired carbonates and sandstones with the same porosity but completely different permeabilities and hence production capabilities.