The Relationship Between Redox State and Methane Concentrations: Implications for Pre- and Post-Drill Sampling
Thursday, November 13, 2014: 10:50 a.m.
Lisa Molofsky
,
GSI Environmental, Inc., Houston, TX
John A. Connor, PE, PG, DE
,
Groundwater Services Inc., Houston, TX
Stephen Richardson, Ph.D., PE, PEng
,
GSI Environmental, Inc., Austin, TX
This study investigates the relationship between prevailing redox conditions and dissolved methane concentrations in more than 800 pre-drill residential water well samples from Susquehanna County, Pennsylvania. For each sample, redox state was determined using threshold concentrations for redox indicator parameters (e.g., nitrate, iron, manganese, and sulfate). In addition, the water type (i.e., Ca-rich vs. Na-rich) and topographic location (i.e., valley vs. upland) was determined for each sample. Based on this information, we identified a combination of environmental factors (i.e., advanced redox state, Na-rich water type, and valley setting) that are strongly related to naturally elevated methane concentrations in water wells. Given a fundamental understanding of the relationship between the microbial oxidation of methane and groundwater geochemistry, we assess the changes in water geochemistry that may be expected from a sudden new influx of methane in these water wells.
Lisa Molofsky, GSI Environmental, Inc., Houston, TX
Lisa Molofsky is a registered Geologist-In-Training (GIT) with GSI. She received an M.S. degree in Geochemistry from the University of Arizona and a B.A. degree in Geology from Washington University in St. Louis. Since joining GSI in 2009, she has conducted research on the nature, occurrence, and cost of oilfield remediation projects, water resource management issues associated with hydraulic fracturing, and the identification and quantification of sources of variability in groundwater monitoring. Molofsky co-authored articles in the Oil & Gas Journal (2011) and Groundwater (2013) concerning methane stray gases in water wells.
John A. Connor, PE, PG, DE, Groundwater Services Inc., Houston, TX
Mr. John Connor is President of GSI Environmental Inc. of Houston Texas and has over 26 years experience in environmental engineering, with specialization in groundwater hydrology, risk assessment, and environmental remediation. Mr. Connor has evaluated radionuclide problems in groundwater both in the United States and internationally and has two U.S. patents on the remediation of radionuclide-contaminated groundwater by means of in-situ immobilization techniques. Mr. Connor has authored numerous publications on environmental risk assessment and remediation and has conducted professional training on these issues throughout the U.S., Canada, Saudi Arabia, and Latin America.
Stephen Richardson, Ph.D., PE, PEng, GSI Environmental, Inc., Austin, TX
Stephen Richardson is an Environmental Engineer with GSI with more than 11 years of experience in soil and groundwater remediation, environmental site investigation, engineering design, and research and development. He is a Licensed Professional Engineer in Texas, Louisiana, North Carolina, and Alberta, Canada. He holds a doctoral degree in environmental engineering from the University of North Carolina at Chapel Hill, an M.S. degree from Louisiana State University, and a B.A.Sc. degree from the University of Waterloo, Canada. Currently, Richardson serves as the technical lead for a DOE-funded research project examining the environmental effects of shale gas operations, specifically air emissions, stray gas events, and flowback/produced water.
