Page 41 - Geology of Carbonate Reservoirs

Influence on Reservoir Performance ne permeability May confi to horizontal direction Prounounced bedding inclination, repetitive sets, and common textural uence both variability infl porosity and permeability; correlation of individual cult beds is diffi May be permeability barriers; may affect porosity distribution Pronounced bedding,

Environmental Association Sediment “ sinks ” — areas of low - velocity fluid motion; may be protected shallows, deeper zones below wave agitation, and areas free from current scour Eolian dunes, slope - break “ spillover lobes ” ), calcarenites ( sandwaves with high rate of sedimentation Exposure surfaces on land or paleo - highs, tidal flats and i

Physical Processes, Their Sedimentary Structures, and Influence on Reservoir Properties

Descriptive Characteristics May be even, wavy, or nodular; continuous or not over distances; beds parallel or not; thicknesses from millimeter to meter scale Curved, convex - upward bedding where lower boundaries of bed sets are nonerosional; scale varies from centimeter to multi metersize; bed curvature diffi to detect in small Abrupt change in beddin
m - scale - cult - diameter cores - upward bedding; ll fl

Sedimentary Structures Ordinary bedding “ planes ” with variations due to surface irregularities, bioturbation, or diagenesis Commonly called “ spillover beds ” or “ simple cross stratification ” Trunated surfaces, channels, “ sharp ” contacts between lithological units; unconformities and disconformities Migrating sets

views
TABLE 2.1 Formative Processes Deposition only — Ordinary bedding Deposition only — Cross bedding Erosion only Erosion with deposition

22