Print this pageExamination of the Queenston Delta in Central New York for Geologic Carbon Dioxide Storage
The late Ordovician Queenston Delta of central New York is composed of the Oswego and Queenston formations, and a statewide reconnaissance by the New York State Museum highlighted it as a potential target for subsurface geologic carbon dioxide storage. The Oswego Formation is un-fossiliferous greenish-gray sandstones, siltstones, and shales that were deposited in offshore shelf to intertidal environments. The conformably overlying Queenston Formation is a sequence of shales and sandstones primarily deposited in non-marine conditions. An unconformity separates the Queenston Formation from the overlying Medina Group. Well log data indicate that both the Queenston and Oswego formations thicken to the southwest region of the study area.
Based on analysis of fifty-two central New York well log suites (gamma, neutron, sonic, and density logs from Broome, Cayuga, Chenango, Chemung, Schuyler, Seneca, Steuben, Tioga, and Tompkins Counties) of the Queenston and Oswego formations, we divide the two formations into thirteen discrete petrophysical zones (Queenston A-F, Oswego A-G). Porosity, density, thin section, and limited permeability data suggest that the zones with the best carbon dioxide storage potential are Queenston B and C, which are located near the top of the Queenston Formation. Though Queenston A is a texturally mature, medium grained quartz sandstone, it is well cemented with little porosity, and erosionally and depositionally thins eastward. Queenston B is a medium to coarse grained quartz sandstone with few shaley beds. Queenston C is more variable, ranging from a very fine to coarse sandstone with varying degrees of hematite cement. Both Queenston B and C thin to the east and shale content increases westward. For both zones, neutron and sonic porosities are greatest in the center of the study area. Queenston A, B, and C all have intra-granular quartz porosity, which may have formed from leaching during a period of exposure prior to the deposition of the Medina Group. Though neutron logs suggest porosity may increase with depth in the Oswego Formation, thin section and sonic log data imply instead that the high neutron log values may be affected by shale water content. Shale and well cemented sandstone in the lower portion of the overlying Medina Group could serve as an immediate seal. Although in general the Medina Group has little inter-granular porosity, assessment of its sealing potential awaits study of its fracture permeability.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009