Quantification of Uncertainty in Shale Gas Resources

Recent advances in fracturing and horizontal drilling technology have made unconventional petroleum resources increasingly important to the oil and gas industry in Alberta. The term shale gas has largely become a catchall phrase to describe any unconventional plays that require fracturing, including shale gas, shale oil, tight gas, tight oil, and hybrid laminated reservoirs. With the emergence of these new sources of oil and gas, quantification of the resources has become a topic of major interest. The lack of much historical data, sparse sampling of shale formations, and a relative lack of understanding of unconventional reservoirs leads to large uncertainty in shale gas resource estimates. The Energy Resource Appraisal group of the Energy Resources Conservation Board has developed a methodology for quantifying the uncertainty in shale gas resource estimates in a geostatistical, data-driven framework that accounts for as many sources of uncertainty as possible.

The methodology presented in this report is to calculate shale and other continuous unconventional resources for which few wells are available for data collection and little or no production history is established. The methodology has proven to be robust regarding data availability to determine resource endowment for a formation and also to identify areas where land sales and drilling may first occur.