Characteristics of discrete and basin-centered parts of the Lower Silurian regional oil and gas accumulation, Appalachian basin: Preliminary results from a data set of 25 oil and gas fields
U.S. Geological Survey Open-File Report 98-216
Appendix A
Adams/Waterford/Watertown gas field (A/W/Wt)
| Location: | Washington County, Ohio (Adams, Waterford, Watertown Twps.) |
| Discovery date: | 1970s; extensively developed in the 1980s |
| Depth (ft): | 5,800 to 6,000 |
| Hydrocarbon type and GOR: | Nonassociated gas; some condensate (60 to 61° API gravity) |
| Structural setting: | East-southeast dipping homocline; near the Cambridge arch; irregular structural contours suggest northwest-southeast trending basement faults |
| Stratigraphic name of reservoir: | "Clinton" sands and Medina sand |
| Trap: | Stratigraphic; influenced by local structures and fractures; no recognizable updip pinchout of sandstone reservoirs |
| Porosity: | F ave (core) = 6%; F lower "Clinton" ave (core) = 4%, range 3.3 to 6%; F medina ave (core) = 4%, range 2.9 to 5.4% |
| Permeability: | Kave = 0.36 mD; Klower "Clinton" ave (core) = 0.02 mD, range 0.01 to 0.03 mD; K medina ave (core) = 0.01 mD |
| Natural fractures: | Noted in core; fractures are considered important for improved reservoir quality |
| Diagenetic features: | Clay = 2 to 4% of reservoir; complex diagenetic history with several stages of cementation, dissolution, and quartz overgrowths |
| Water saturation and volume/salinity of produced water: | Sw (ave) = 26.9%, range 8 to 74%—based on 4 logs; not much water is produced; ´ =11BW/MMCFG, sample number = 26, range <1 to 35 BW/MMCFG |
| Gas/water and oil/water contacts: | None reported |
| Reservoir pressure: | 1,500 to 1,600 psi (0.27 psi/ft) |
| Bottom-hole temperature: | 112° F (in nearby wells in Washington County) |
| Well spacing: | 80 acres |
| Ultimate production (EUR per well): | 95th percentile (F95) = 39 MMCF of gas, 50th percentile (F50) = 98 MMCF of gas, 5th percentile (F5) = 280 MMCF of gas, sample number = 26; these are minimum EURs because they only represent 11 years of the well’s production |
| References: | Baranoski (1993); Bush and others (1987); Core (1986); Janssens and Olds (1993); Ohio Division of Oil and Gas (1997); Root and Martin (1995) |
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