Enhanced Gas Recovery and CO2 Storage in Gas Shales: A Summary Review of its Status and Potential

AbstractThis paper reports on research sponsored by the U.S. Department of Energy (USDOE) to assess factors influencing enhanced gas recovery (EGR) and CO2 storage in selected gas shales in the Eastern USA [1]. The paper also summarizes work sponsored by the IEA Greenhouse Gas R&D Programme (IEAGHG), which builds upon the lessons learned regarding EGR and CO2 storage in the U.S., combined with a global assessment of shale gas potential [2], to develop a high-level estimate of the potential for EGR and CO2 storage in gas shales globally [3].In total, the four selected shale gas plays in the Eastern USA addressed in this assessment cover an area of 470,000 square kilometres (182,000 square miles). These shales may contain an estimated 170 trillion cubic meters (Tcm) (6,000 trillion cubic feet (Tcf)) of gas in place, and have a maximum theoretical storage capacity of over 600 billion metric tons (gigatonnes, Gt). Accounting for assumptions about the portion of the gas in-place in these shale plays that may be recoverable, and the portion of this recoverable resource that could be economic to produce using EGR techniques with CO2 injection, nearly 34Tcm (1,200 Tcf) of EGR potential is estimated to be associated with the injection of CO2 into these shale gas plays. Of this, 13Tcm (460 Tcf) could be economic to recover with reasonable gas prices and/or modest incentives. This could facilitate the storage of nearly 50 Gt of CO2.Building upon this work, as well as an assessment by the U.S. Energy Information Administration (USEIA) that provides a “first- order” view of the gas in-place and technically recoverable resource for 48 shale gas basins and 69 shale gas formations in 32 countries, an estimate was developed of the global the potential for EGR and CO2 storage in gas shales [3]. An estimated 188Tcm (6,600 Tcf) of shale gas resources are potentially technically recoverable globally (not including consideration of the potential EGR realized as a result of CO2 injection in shales). This could facilitate the potential storage of 740 Gt of CO2 in gas shales. Of this, as much as 71Tcm (2,505 Tcf) could be economic to produce with EGR, and could facilitate the economic storage of 280 Gt of CO2