Print this pageDepositional Investigation and Analysis of 
Porosity
Development in a Northwestern Oklahoma Cherokee Sandstone, Using Petrographic
Image Analysis
Gregory L. Scheffe, W. E. Full
Recent technological advances allow image analysis of porosity networks in
rock, using a computer-based Petrographic Image Analysis System (PIA) developed
at the University of South Carolina. PIA processes digitized scenes of the
porosity network, quantifying the characteristics of each pore. Pattern
recognition and/or classification algorithms (CABFAC and QMODEL) are used to
determine the mixing components that define the pore complex. Comparisons of the
quantified pore attributes to petrophysical values (e.g., permeability) enable
us to predict these values with high precision. This procedure identifies the
variables that control the value of the petrophysical parameter.
A study of the Bartlesville sandstone member, Cherokee Group, Pennsylvanian
System in northwestern Oklahoma, used the procedures as outlined in defining
characteristics of this petroleum reservoir. The investigation identified the
reservoir as deltaic. PIA and the unmixing algorithms determined the existence
of five pore types that contribute to the reservoirs development. Statistically
derived relationships predicted the permeability with an R2 value of
0.93. The highest prediction resulted from the pore type and quantified pore
attributes that characterize small pores occurring in high density and
exhibiting small to moderate perimeter roughness. This pore type occurs in
quartz sandstone laminations with alternate layers containing a small percentage
of calcite, fossil fr gments, and clay. This type of lamination occurs in very
fine cross-bedded and contorted sedimentary deposits. This type of sedimentary
structure also restricts permeability
. Reservoir production seems related to a
system of fractures and micro-fractures.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.