Figure 11. Net pay isopach map of: (a) combined oolite bar subzones “A₂” and “A­₃” are separated vertically by an effective flow barrier of shaly carbonate mudstone (b) “A₂” subzone – a shaly carbonate mudstone separates this subzone from the “A₃” subzone (c) “A₃” subzone. “A₂” and “A₃” subzones are located in the San Andres Reservoir, “C” waterflood unit, Permian basin, Texas.