Soil Gas

 


Dr. Fountains research on the use of soil gas to delineate fracture systems has been ongoing since 1992.  This research includes major studies of the Clarendon Linden Fault Zone with Dr. Robert Jacobi and of the Akzo-Nobel Retsof salt mine collapse that occurred in 1994 after which soil gas studies were used to predict areas of future collapse.  Soil gas studies are continuing in the finger lakes region, in the southern tier in the Bath area, and in the Gowanda area as part of sponsored research designed to illustrate the use of remote sensing and soil gas in delineation of buried bedrock structures.  The research is investigating applications both to characterization of the hydrology of sites and for location of fractured-reservoirs for oil and gas.


 

Soil Gas Theory

Gases that accumulate in the pore spaces of sediment, in the vadose zone, are referred to as soil gases.  The gases that are predominately of interest are methane and ethane.  The gaseous hydrocarbons seep from the source rock through faults and fractures, and to a minor degree by diffusion, and accumulate in the overlying soil.  For years, soil gas surveys have been useful in determining subsurface structures where bedrock exposure is poor. Studies have shown that surface geochemistry, in the form of gaseous hydrocarbons, can be helpful in locating deep oil and natural gas reservoirs. Faults can serve as conduits for gas accumulation at the surface.  Methane and ethane gas concentrations were high in the regions over the gas reservoirs but higher in regions that were associated with faults.

The detection of buried geologic structures in relatively thin sedimentary cover and the mapping of those structures by the use of soil gas anomalies is well documented by Jacobi and Fountain.  Using soil gas as one of several methods successfully mapped major faults and fractures of the North-South trending Clarendon-Linden Fault System in Western New York.

It is necessary to distinguish between thermogenic and biogenic methane to determine if the soil gas anomaly is a product of a hydrocarbon reservoir source.  Methane (CH4) can be produced from two distinctly different processes. The controlling factor is the environment from which it is formed that determines the type of methane (microbial or thermal).  Microbial Methane is produced from microorganisms (Methanogens) with the presence of water and organic compounds in a anaerobic environment at a relatively shallow depth (0-1 km).  Thermal methane and ethane (C2H6) are produced by the genetic/post-genetic fractionation of a carbon source trapped within the subsurface rock (1-7 km), whereas heat and pressure are the controls. 

 

Gowanda Soil Gas Study:

Soil gas studies were undertaken to investigate the existence of CSD's, Cross-Strike Discontinuities, in a portion of the bass island oil and gas reservoir in Western New York State.  Production from the bass island structural trend is entirely dependent upon fracturing of Devonian and Silurian rock units in the form of thrust faults, tear faults and cross-strike discontinuities which mark offsets in the major structure.  The location of CSD’s are important for their significance in the extraction and storage of natural gas and oil. Open fractures can provide preferential pathways for the migration of thermogenic gases primarily methane and ethane to the surface. 

The results from the Gowanda study has demonstrated the usefulness and applicability of soil gas analyses in locating and characterizing subsurface, hydraulically active, fracture zones (CSD’s) related to oil and gas prospects along the Bass Island Trend in the Dayton and Persia townships.

     

The primary goals of the soil gas research at the University of Buffalo are to:

1.  Delineate the migration of light hydrocarbons through fractured rock.

2.  Determine if faults and fractures can manifest into surface expressions in the form of Lineaments.

3.  Establish  the correlation between soil gas surveys and FID's (Fracture Intensity Domains) in exposed bedrock.

4.  Determine the effectiveness of soil gas for petroleum exploration, specifically for delineation of fractured reservoirs.

 

Previous Works:

1.  Understanding fault and fracture dynamics in the Retsof Mine, NY collapse (formerly the largest salt mine in the world) and in the Solvay Mine, WY 

2.  Definition of fault and fractures in salt storage caverns 

3.  Oil and gas exploration 

4. Identification of zones of permeable vertical fractures, implications for water resources  (hydrology) and site characterization (contaminant hydrology).

5. Determination of the extent of fracturing of post-glacial sediments in New York, specifically fractures parallel to basement structures. Implications for Neotectonics and for ground water flow.

 

Clarendon Linden Fault Zone

Soil Gas Sampling

The sights of field research

The above picture is of a fractured Devonian shale formation which is approximately 150 feet high from which reservoir gas can migrate. 

Soil Gas Probe

Soil gas probe used for field investigations.

Recording fracture orientation 

 

 

NW Fracture

Idealized CSD structure.


 

Theses:

Hegarty, Denis: "The Use of Soil Gas for the Study of Subsidence in Cuylerville, NY Area", Masters Thesis, 1997.

Paquette, Lisa: "The Use of Soil Gas Analyses for the Evaluation of Potential Gas Leakage From a Petroleum Storage Facility. Case Study - Bath Petroleum Storage Inc. Bath, New York", Masters Thesis, 1998. 

Travis Nelson: "The Use of Soil Gas Surveys to Delineate Subsurface Structure for Oil and Gas Prospects of the Bass Island Trend: Cross-Strike Discontinuity Locations for Cherry Creek, Perrysburg, Gowanda and Collins Center Quadrangles, Western New York", Masters Thesis, 2002.

Lucas Budny: Seneca Lake Soil Gas Project, detection of fractured reservoirs, Masters Thesis, 2002.

Richard Bieber: Soil Gas Investigations for Delineation of Buried Fractures & Faults, Zoar Valley Gas Storage Field, Masters Thesis, 2002.

 


 

Dr. John C. Fountain

Publications, Abstracts, & Technical Reports by Research Area

Fracture Publications:

Jacobi, R.D. and J.C. Fountain, (1993). "The Southern Extension and Reactivation of the Claredon-Linden Fault System", Geographic Physique et Quat. 47: 285-302. 

Fountain, J.C., R.J. Jacobi, (1997). "Detection of buried faults and fracture systems using soil gas", Submitted to: Geology, 9pp.

Fracture Abstracts:

Jacobi, R.D. and J.C. Fountain, (1988). Structural and geochemical transect across the Rowe-Hawley Zone, central Mass.: Geol. Society of America, Abstract with Programs, NE section, 20(1):29.

Fountain, J.C., R.D. Jacobi, and G. Gill, (1989). Detection of bedrock faults in covered areas through the use of soil-gas surveys: A case study on the Clarendon-Linden Fault, N.E. Sect. Geol. Soc. Amer., Abstract.

Jacobi, R.D., J.C. Fountain, and G. Gill, (1989). Evidence for the continuation of the Clarendon-Linden Fault System into central Allegany County, New York. N.E. Sect. Geol. Soc. Amer., Abstract.

Cohen, A. J., and J.C. Fountain, (1996). "Innovative Approaches to Characterizing Geometry and Flow Patterns in Fractures." In: Abstracts with Programs of The Geological Society of America's 31st Annual Northeastern Section, Buffalo, New York 28(3):46.

Fountain, J.C., T.D. Jacobi and M.P. Joy, (1996). "Detection of the Clarendon-Linden Fault System, Allegany County, New York Using Soil Gas Analyses", In: Abstracts with Programs of The Geological Society of America's 31st Annual Northeastern Section, Buffalo, New York, 28(3): 55. 

Hegarty, D., M. Joy and J.C. Fountain, (1996). "The Use of Soil Gas Data for the Study of Subsidence in the Cuylerville, N.Y. Area Since March 1994", In: Abstracts with Programs of The Geological Society of America's 31st Annual Northeastern Section, Buffalo, New York, 28(3):63. 

Jacobi, R. D., J.C. Fountain, J. Burley, S. Korff, L. Kracker, and C. Zent, (1996). "Utilization of a GIS (ARC/INFO) for Compilation of Cultural and Geological Data in Land Use Considerations: Allegany County, New York State." In: Abstracts with Programs of The Geological Society of America's 31st Annual Northeastern Section, Buffalo, New York, 28(3):67.

Jacobi, R.D., J.C. Fountain, M. Zhao, G. Smith, T. Peters, (1996). "Character and Reactivation History of the Clarendon-Linden Fault System: Evidence from New York  State", In: Abstracts with Programs of The Geological Society of America's 31st Annual Northeastern Section, Buffalo, New York, 28(3): 67.

Fracture Technical Reports:

Jacobi, R and J. C. Fountain, March (1995). Seismic Potential of the Clarendon-Linden Fault System in Allegany County, Submitted to New York State Research and Development Authority, 1708 p.

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