Shale Gas & Oil Terminology Explained: Reserves and Estimates

The document provides a glossary of terms for shale gas and oil resources. It distinguishes between undiscovered resources (believed to exist but not precisely located) and discovered resources. It further differentiates between technical recoverability (extractable using current technology) and economic recoverability (financially feasible based on market conditions). Finally, it categorizes reserves by certainty levels: proven (usually >90% certainty), probable, possible, and other (inferred or indicated) reserves.

• Resources are categorized as either undiscovered, where a "precise location has not yet been determined", or discovered, where the "exact location has already been determined".
• Technical recoverability refers to deposits extractable with current technology, whereas economic recoverability depends on "financial incentives and market conditions". For example, a price increase from $3.50/mmBTU to $4.50/mmBTU can make a deposit economically recoverable that was previously considered uneconomic.
• Estimates of undiscovered technically recoverable natural gas are not considered an accurate measure of likely fracking activity because they do not account for "geographic and geological concerns" such as "the location of local aquifers or the depth of the well".
• Reserves are classified by certainty: proven reserves have a certainty of quantity and location that is "usually greater than 90 percent" and are reported to the Securities and Exchange Commission as capital assets. Probable reserves are "more likely than not to be recovered", while possible and other (inferred or indicated) reserves have lower levels of certainty.

APA

Glass, K. (2011). Shale Gas & Oil Terminology Explained: Reserves and Estimates. Environmental and Energy Study Institute. https://www.eesi.org/files/fracking_estimates_111611.pdf

Chicago

Glass, Kate. Shale Gas & Oil Terminology Explained: Reserves and Estimates. Environmental and Energy Study Institute, 2011. https://www.eesi.org/files/fracking_estimates_111611.pdf.

Wikipedia

{{cite report |last1=Glass |first1=Kate |title=Shale Gas & Oil Terminology Explained: Reserves and Estimates |publisher=Environmental and Energy Study Institute |date=November 2011 |url=https://www.eesi.org/files/fracking_estimates_111611.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{glass2011shale, author = {Glass, Kate}, title = {{Shale Gas \& Oil Terminology Explained: Reserves and Estimates}}, institution = {Environmental and Energy Study Institute}, year = {2011}, month = nov, url = {https://www.eesi.org/files/fracking_estimates_111611.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }