US Geological Survey Open File Report 98-216 Index

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

Robert T. Ryder

U.S. Geological Survey Open-File Report 98-216

Any use of trade, product, and firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government

Contents

Abstract
Introduction
Availability of relevent oil and gas field data
Comparison of selected oil and gas field characteristics
    Depth to production and hydrocarbon types
    Structural setting and natural fractures
    Trap types
    Reservoir porosity and permeability
    Reservoir water saturation and volume and composition of produced waters
    Segregation of gas and fluids in reservoirs
    Reservoir pressure and bottom-hole temperature
    Ultimate gas recovery per well
Discussion
Conclusions
References Cited
Appendices

Illustrations

Figure 1. Map of the northern part of the Appalachian basin province (067) showing oil and gas plays in the Lower Silurian "Clinton" sands, Medina Group sandstones, and Tuscarora Sandstone identified in the 1995 USGS National Oil and Gas Assessment.

Figure 2. Map of the regional hydrocarbon accumulation in Lower Silurian sandstone reservoirs of the Appalachian basin, U.S. and Canada showing oil and gas fields used in the report. Also shown is the approximate boundary between discrete and basin-centered parts of the accumulation.

Figure 3. Correlation chart of Niagaran Provincial Series rocks (Lower to lower Upper Silurian) in the area of the regional accumulation.

Figure 4. Plot depth to production vs. hydrocarbon type for oil and gas fields.

Figure 5. Map of the regional hydrocarbon accumulation in Lower Silurian sandstone reservoirs of the Appalachian basin showing oil and gas fields used in this report. Also shown is the approximate updip limit of the basin-centered (deep basin) gas accumulation and adjoining water-block trap of Davis (1984) and Zagorski (1991).

Figure 6. Plot of reservoir porosity vs. reservoir permeability for oil and gas fields.

Figure 7. Plot of reservoir water saturation vs. depth to production for oil and gas fields. Also shown are the volume and salinity of produced waters.

Figure 8. Plot of reservoir pressure vs. depth to production for oil and gas fields.

Figure 9. Plot of bottom-hole temperature vs. depth to production for oil and gas fields.

Figure 10. Probability plot of estimated ultimate recover (EUR) of gas per well in the Northeast Salem field.

Figure 11. EUR per well distributions for discrete and basin-centered parts of the regional accumulation.

Figure 12. Generalized model of origin and modification of the Clinton/Medina basin-centered gas accumulation and adjoining discrete and hybrid accumulations.

Figure 13. Map showing discrete, hybrid, and basin-centered parts of the Clinton/Medina/Tuscarora regional hydrocarbon accumulation.

Tables

Table 1. Summary of oil and gas fields in Ohio, Pennsylvania, and New York that constitute the dat set in this report.

Table 2. Summary of local and regional structural elements imprinted on the north- to northeast-striking structural trend of the Appalachian basin.

Table 3. Summary of trap types.

Table 4. Summary of produced water.

Table 5. Summary of gas and oil EUR per well distributions.

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