6. Colorado, Champlin #8 McCormick 49-3

Source: Hartman, D. J., 1990, Evaluation of the Morrow Sandstone in Sorrento Field, Cheyenne County, Colorado: Morrow sandstones of southeast Colorado and adjacent areas, Rocky Mountain Association of Geologists, pp. 91-100.

Morrow Sandstone in Sorrento Field, well: Champlin #11CPC 22-3 McCormick

This sandstone is interpreted as a valley-fill deposit. Capillary pressure measurements were performed and interpreted by Hartman. Port Size was used in his analysis, defining as the pore size at 35% mercury injection. The sandstone shows a general trend of increasing Port Size with depth.

The Pickett cross plots constructed by PfEFFER reveal a trend of constant porosity with declining resistivity and increasing BVW and Sw with depth. This suggests that the reservoir is in a transition zone. The water saturation increases downward from about 33% to approximately 100%. BVW increases downward from 5 to 15%. The sandstone is shaly at the top with a Port Size (R35) of 0.2 to 0.5 micrometers. A cleaner sandstone is found at the base with an R35 of 10 to 50 micrometers. The main pay zone is more homogeneous with 20% porosity and an R35 of 10 to 15 micrometers. The horizontal trend of points with decreasing resistivity with depth is concluded to represent a transition zone. Overall, the reservoir increases in pore size with depth which is probably related to an increase in grain size. Unfortunately, the best reservoir quality rock lies below the oil:water contact. The well was perforated for 98 BOPD and 300 MCFGPD.