New York Trenton and Black River Play
The Trenton Formation (North Central New York) >> See map here <<
The first discoveries of natural gas in the Trenton Formation were drilled and completed near the Villages of Sandy Creek and Lacona, Oswego County around the 1890s. This field supplied gas to these villages until the 1940s. Numerous other small Trenton gas fields have been discovered in and around the Syracuse area over the last 100 years. These shallow wells tend to have high initial reservoir pressures and flow rates. However, they decline very rapidly and in most cases these wells become marginal producers, which serve as domestic house gas.
Most of the gas production from individual Trenton wells is from relatively few fractures that these wells have interconnected with. These fractures are small macro and microscopic natural cracks that occur throughout the thick regional limestone that makes up the Trenton Formation in most of New York State. Unfortunately, there is no intergranular porosity and these fractures can store very little natural gas.
Hopefully, some day drilling and completion technology will advance to the state that these natural gas reserves will become an economic resource.
The Black River Formation (South-Central New York)
The first discoveries of natural gas in the Black River Formation where made in the late 1990s by Columbia Natural Gas in northern Steuben County. These natural gas reservoirs are very different from the Trenton reservoirs described above. The reservoirs are deep (8,000 feet and deeper), fault controlled grabens. The faults allowed hot hydrothermal fluids circulating up from very deep basement rocks to alter the regional limestone of the Black River formation. These fluids are what created the dolomitic reservoirs so highly prized in this part of south-central New York.
The Reservoir Characterization Group at the New York State Museum has put together a report detailing the Black River Play in New York. We have included some excerpts from that report here.
For a complete and printable version of that report please >> click here <<.
Hydrothermal Dolomite Play >> Click to view map <<
- Fault controlled, Ordovician carbonates-generally found at depths greater than 8,000 feet
- Reservoirs occur in structural lows in patchy matrix dolomite and brecciated zones
- Fluid inclusions, stable isotopes, trace elements and petrography all support a hydrothermal origin for the dolomite
- Structural depressions are visible on seismic and form over extensional pull-aparts that developed during the Ordovician Taconic Orogeny
T/BR Discovery Field
Dolomite only occurs around faults and extends laterally in more porous rocks at tops of sequences. These rocks probably had fairly low perm prior to alteration
Seismic Over Discovery Field
There are tight dolomite wells in and around most good Trenton Black River Fields. A corollary of this is that there are likely to be good productive wells near tight dolomite wells.
Trenton - Black River Wells can be risky
Over 350 wells have been drilled in search of these TBR hydrothermal reservoirs in the counties of South Central New York. About 100 of these wells have been succesfull at finding some quantites of natural gas. Some of these wells are not commercial successes. However many of these wells are very prolific natural gas wells. >> See reserves <<
Stueben, Chemung, and Schyler Counties have been the focal point from these commercial wells.
Trenton - Black River wells are expensive
TBR wells can cost at much as $4.5 million dollars to drill and complete. Another additional $1 millon to $3 million dollars can be spent getting these wells connected to the regional natural gas markets.
