Recommended Practices for Baseline Sampling of Water Wells in Areas of Shale Gas Development
Tuesday, April 25, 2017: 12:50 p.m.
Stephen Richardson, Ph.D., PE,
,
GSI Environmental, Inc., Austin, TX
Lisa Molofsky, P.G.
,
GSI Environmental, Inc., Houston, TX
Anthony Gorody, Ph.D., P.G.
,
Universal Geoscience Consulting, Inc., Houston, TX
Fred Baldassare, P.G.
,
Echelon Applied Geoscience Consulting, Murrysville, PA
Ann Smith, P.E., BCEE
,
GSI Environmental, Inc., Austin, TX
John A. Connor, PE, PG, DE
,
GSI Environmental, Inc., Houston, TX
Baseline sampling of residential water wells is standard practice for operators in many areas of shale oil and gas development. Data collected from these sampling programs is critical for evaluating whether reported changes in local water quality (e.g., methane, salts, metals) are related to nearby drilling activities, or potentially naturally occurring. However, little guidance is available to operators, regulators, and contractors to support the development of sampling programs and interpretation of data.
Our research project, funded by the Department of Energy, evaluated key sources of variability in baseline sampling results from water wells in Northeastern Pennsylvania. Multiple sampling events were conducted over a two-year period. Measured parameters and analytes included daily water usage, water levels, dissolved gases, stable isotopic analyses of methane, water, and dissolved inorganic carbon, major and trace ions, and field parameters. Results culminated in the development of recommended practices and guidance for dissolved gas sampling methods, well purging practices, and expectations for temporal variations in methane concentrations and methane-geochemical parameter relationships. Key findings and recommendations of this study include:
- Sample collection method can significantly affect the resulting methane concentration; a closed-system method yields the most accurate methane concentrations under effervescing conditions.
- Purging twice the volume of water in the pressure tank and lines is typically adequate for the collection of baseline samples for analysis of dissolved methane concentrations. Such water volumes are reasonably representative of the water quality regularly consumed by residents.
- For wells with dissolved methane concentrations greater than 1 mg/L, changes in concentration greater than two-fold over the two-year period were not commonly observed.
- At a subset of wells, changes in methane concentrations were significantly correlated with changes in sodium and other salinity indicators, where parameters varied according to the dynamic mixture of fresh and saline water sources in the wells.
Stephen Richardson, Ph.D., PE,, GSI Environmental, Inc., Austin, TX
Dr. Richardson is an Environmental Engineer at GSI with fifteen years of consulting/research experience in soil and groundwater remediation and environmental site investigation. Dr. Richardson is a Licensed Professional Engineer in Louisiana, North Carolina, Texas, 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. He served as the technical lead for a recently completed DOE-funded research project examining the environmental effects of shale gas operations, specifically air emissions, dissolved gases in groundwater, and flowback/produced water characterization. Currently, he serves as a technical advisor on two DOE NETL research projects focused on measurement methods and technologies to quantify methane emissions from i) natural gas compressors in the gathering segment and ii) natural gas storage wells and fields.
Lisa Molofsky, P.G., GSI Environmental, Inc., Houston, TX
Lisa Molofsky is a professional geologist 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 several recent articles in the Groundwater journal concerning baseline sampling and methane stray gas migration in water wells.
Anthony Gorody, Ph.D., P.G., Universal Geoscience Consulting, Inc., Houston, TX
Anthony Gorody is a geoscientist with more than 30 years of diverse international and domestic oil and gas industry experience. His technical specialty relates to state-of-the-art forensic geochemical fingerprinting and hydrogeologic characterization techniques useful for evaluating natural gas resources, groundwater and surface water resources, produced water, and pollution in the near-surface hydrogeologic environment. An industry leader in baseline environmental measurement and monitoring programs, Gorody provides both consulting and training services.
Fred Baldassare, P.G., Echelon Applied Geoscience Consulting, Murrysville, PA
Fred Baldassare is Principal Geoscientist and owner of Echelon Applied Geosciences Consulting. He has more than 20 years of experience investigating incidents of stray gas migration. He previously served as the statewide consultant for the Pennsylvania Department of Environmental Protection for investigating and characterizing sources of stray carbon dioxide and methane. Baldassare helped pioneer the application and advancement of isotope geochemistry to identify the origin of stray and natural gases in the Appalachian Basin. He has authored and co-authored numerous professional papers for peer-reviewed publications on the application of isotope geochemistry.
Ann Smith, P.E., BCEE, GSI Environmental, Inc., Austin, TX
TBA
John A. Connor, PE, PG, DE, GSI Environmental, Inc., Houston, TX
Mr. John Connor is President of GSI Environmental Inc. of Houston Texas and has over 30 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.
