| The Shaly Sand
Advisor (SSA) is an exciting log interpretation tool co-developed by The
Logic Group and Dr. George Asquith. The Shaly Sand Advisor provides a
systematic approach for the special problem of analyzing shaly sand
formations. The SSA program takes the user through a
complete analysis including a first pass which computes clay volumes and
effective porosities. A series of crossplots help determine of the formation
should be classified as a shaly sand and show if the formation appears
productive and hydrocarbon bearing. Total porosity is computed based
upon available logs, either porosity logs or resistivity logs. Effective
porosity is computed by subtracting the shale effect from the total
porosity. True resistivity is computed including tool corrections and
tornado chart correlations. |
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| Being able to accurately estimate the clay
volume is important to all shaly sand water saturation models. Using the SSA
program the clay volume can be estimated from different log curves: gamma
ray, porosity, spectra-log, and SP. If lab data for the well or a
nearby well is available, the clay volumes can be crossplotted with the log
results to generate transformations for calculated the true clay volume. Several crossplots including a Dew Plot,
Q-Plot, and BVW Plot are presented to aid users in identifying gas or
hydrocarbon bearing zones, low clay volume formations, clay type (dispersed
or laminar), and producible formations. Water saturation can be computed for
low salinity (high Rw), low volume of clay, dispersed clay, or laminar shale
formations. The program compares water saturation techniques which aid
in helping analysts determine shale type.
SSA is a menu driven program
with instructions appearing on-screen. Technical notes are provided
through help screens and provide discussions about crossplots and equations.
SSA provides users with a step-wise procedure to analyze shale sands. More
information is contained on the other pages of this website. SSA runs
on IBM-PC compatible computers and is available from The Logic Group.
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