Figure 23—Photomicrographs of diagenetic features and pore morphologies. 

(A). FCD Robert No. 1-8  (8-24N-6W): 6421 ft--Staining with potassium-ferricyanide shows zoned dolomite with iron-rich episodes (blue) suggesting incremental accretion of dolomite during diagenesis; host rock is tightly cemented quartzose sandstone; plane-polarized light. 

(B). Mobil LeForce No. B-2 (23-26N-7W): 5996 ft--Euhedral pyrite crystals replacing grains and filling both primary and secondary pore spaces in quartzose sandstone; plane-polarized light. 

(C). FCD Betty No. 1-16 (16-24N-6W): 6410 ft--Preserved intergranular primary porosity in sandstone with significant overgrowths and illitic grain coatings; plane-polarized light. 

(D). TXO Sullivan No. H-4 (34-26N-7W): 6055.5 ft--Secondary porosity due to dissolution of quartz, chert, and detrital matrix; sandstone is quartzose but contains glauconite and scattered dolomite; plane-polarized light.

(E). Monsanto Shrewsbury No. 1 (36-27N-8W): 5862 ft--Secondary porosity due to dissolution of dolomite and matrix with some minor quartz dissolution in quartzose sandstone; crossed nicols.