A Fix Was Found, a New Published Method is Emerging

Shale Oil and Gas
Oral Presentation

Prepared by

Contact Information: rvitale@envstd.com; 610.935.5577


ABSTRACT

The analysis of groundwater for dissolved light gases, including methane, is a required or recommended practice for establishing baseline and post well completion conditions in the vicinity of unconventional shale gas production. Historically, data collected by Operator members of the Marcellus Shale Coalition (MSC) have been of concern due to disparate dissolved methane results in domestic groundwater wells. Furthermore, member companies have identified large variations in the reported concentrations between samples split between accredited laboratories. In previous years we have presented on three separate round robin studies aimed at understanding and minimizing these dissolved gas concentration variances.

The Fix: The information collected from our previous studies resulted in our preparation of a light gas standard operating procedure (SOP). The starting basis of the SOP entailed prior work by multiple laboratories, including those that participated in prior study phases. Synthesis of their individual procedures and, their contributed observations during study execution was paramount to this effort. A draft SOP was first presented to 12 laboratories, ten of which had participated in at least one of the prior phases. The laboratories reviewed the procedure and provided logistic and technical comments in preparation for a collaborative method validation study. The final SOP used as the basis of an interlaboratory study, or “ILS.”
The Validation: In 2019 the MSC commissioned the ILS validation study with participation from twelve laboratories who were provided with replicate synthetically prepared dissolved methane standards at four concentrations, along with two Certified Reference Material (CRM) standards containing multiple analytes (methane, ethane, ethene, and propane). The two CRMs provided definitive accuracy information as they were prepared by an ISO17034-accredited reference material provider. Results of the ILS will be provided; the data are validation of the multi-year effort to develop the analytical approach captured in the SOP.