Real-Time Monitoring System for Evaluating Long-Term Variability in Methane in Domestic Water Wells in Pennsylvania

Debby Mcelreath¹, Charles B. Whisman², Charles Olmsted¹, Denise Good², and Richard Wardrop²
¹Chesapeake Energy Corporation, Oklahoma City, OK, [email protected], [email protected]
²Groundwater & Environmental Services, Inc., Exton, PA, [email protected], [email protected], [email protected]

Naturally-occurring methane, originating from a variety of sources, is present in many domestic groundwater wells in Pennsylvania. A significant amount of data is currently being collected by the oil and gas industry as a result of sampling efforts and investigations much of which is from pre-drilling (“baseline”) sampling events conducted prior to any drilling activity. However, gaps remain in understanding and quantifying the natural variation in methane concentrations. This is of significant importance in assessing gas migration when there is nearby oil and gas activity. This presentation will discuss a research project developed and implemented to gain an understanding of the long-term variability of methane in domestic water wells.

Real-time remote monitoring and data trend analyses are being utilized to understand natural methane fluctuations and correlations between methane headspace concentration and other parameters which could account for changes in the headspace concentration. The project design involved a prescribed selection of the domestic wells and monitoring parameters to be included. Significant efforts were made to prepare the wells for the study including borehole geophysics, upgrades to well equipment, and installation of water treatment systems. Descriptions of the customized real-time remote monitoring equipment, array of well headspace and water quality sensors utilized, and equipment setup will be presented, as well as the associated challenges and logistics. Barometric pressure, water use, well recharge, water level fluctuations, and pump cycling are examples of the variables monitored.

The preliminary results from the on-going pilot study will be presented, including the pilot well construction, water quality, and geologic setting, initial trends and findings, and real-time live display of data. The usefulness of the data and the accuracy/precision of sensors will be discussed. The long-term study will provide further information to better understand the occurrence and causes of methane fluctuations and water well quality issues in Pennsylvania.

AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012