DEPOSITIONAL ARCHITECTURE AND PETROPHYSICAL VARIABILITY OF AN OOLITIC TIDAL SAND SHOAL: PENNSYLVANIAN (MISSOURIAN), KANSAS, USA

摘要

Recent studies of Holocene ooid shoals have demonstrated that hydrodynamics influence sedimentological differentiation among subenvironments, but the ultimate role that these distinctions have on properties in subsurface analogs is less constrained. This study explores how geological variability is captured petrophysically in a Pennsylvanian oolitic succession (Dewey Limestone, Missourian, Cutter Field, Kansas). In the field, the Dewey Limestone ranges from, 10 m) thick; areas with thick accumulations include porosity of greater than 20 and form NW-SE-trending highs, separated by thins of low porosity (<15). An extensive suite of petrophysical logs in one well (Cutter KGS 1) illustrates the character of the strata. Resistivity image logs and dip-meter data motivate a subdivision of the succession into distinct depositional packages. These units include differences in porosity, acoustic (compressional and shear) velocity, velocity anisotropy, and elastic moduli. In addition, apparent porosity exponents (m(a)) were computed from log porosity and array induction deep resistivity.