--> Abstract: Surface Geochemical Expression of Hydrocarbon Seepage Over a Utica-Trenton Play Area, New York

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Surface Geochemical Expression of Hydrocarbon Seepage Over a Utica-Trenton Play Area, New York

S. Duff Kerr1, David M.Seneshen2 and Jay Leaver3

1Kerr & Associates & Thomasson Partner Associates, Denver, CO 80218

2Direct Geochemical, Golden, CO 80401

3Thomasson Partner Associates, Denver, CO 80218

An area north of the Finger Lakes and west of the Adirondacks in New York has produced natural gas from Ordovician Utica-Trenton Group strata since 1889. Of the 365 wells drilled in the area, 223 produced natural gas. Since the late 1960s, this area has seen renewed exploration interest because of the historical production and higher gas prices. Of the 11 wells drilled over the past 5 years, only 4 have had apparent commercial success. Based on these poor drilling results, which were largely seismic-driven, less costly exploration methods were sought to complement seismic surveys. In a recent NYSERDA project, several surface geochemical methods were assessed to determine their value to gas exploration in the area.

Direct Geochemical collected 170 shallow (1-foot) and deep (8-foot) soil samples along public roads over both productive and non-productive areas. The samples were dried, sieved and analyzed for low and high temperature thermally desorbed C1-C8 hydrocarbons and an acid-extract was analyzed for 26 major and trace elements. Conclusions from the geochemical survey are as follows:

Low temperature desorption of deep soils reveals strong methane (up to 1%) and C1/C2 anomalies over and adjacent to productive areas.

High temperature desorbed hydrocarbons in shallow soils better discriminate between productive and non-productive areas than those in deep soils. Variables that contribute most to the discrimination are propane, nButane, methane and nHeptane.

Both shallow and deep soils over productive areas are anomalous in barium, potassium, calcium, magnesium and strontium. In the shallow soils, silver, antimony, thallium and selenium are anomalous near the productive area.

 

AAPG Search and Discovery Article #90059©2006 AAPG Eastern Section Meeting, Buffalo, New York