Herndon1 O'Leary
API 4004105159 · Dewey County, South Dakota · Wildcat field
Plugged and AbandonedDry Hole
API
4004105159
Operator
Herndon Drilling Co.
County
Dewey
Field
Wildcat
Location
Permit
142
Formation tops
South Dakota records 7 formations for this well, shallowest first.
| Formation | Top (ft) | Age |
|---|---|---|
| Niobrara Formation | 1,600 | Cretaceous |
| Greenhorn Limestone | 2,105 | Cretaceous |
| Dakota Mud | 2,565 | Cretaceous |
| Piper Formation | 3,185 | Jurassic |
| Minnelusa Formation | 3,300 | Permian/Pennsylvanian |
| Charles Formation | 3,957 | Mississippian |
| Mission Canyon Limestone | 4,085 | Mississippian |
A dash is a formation South Dakota records for this well without a depth.
Completion
South Dakota files 1 completion report for this well.
Vertical Well
Plugged and AbandonedDry HoleSpudded
1955-09-04
Measured depth
4,214 ft
True vertical depth
4,214 ft
Location
45.256877, -101.253774
45.25688, -101.25377 · Surface location as filed with South Dakota⌘ or Ctrl + scroll to zoom
Every well in Dewey County, South Dakota
South Dakota state record, from SD_wells_SDOILexport_Export__wells_Table_4_Web.parquet. Corpus built 2026-09-11.