A report commissioned by the Energy Information Administration (EIA) estimates that technically recoverable shale natural gas resources in the United States are as much as 750 Tcf.

Approximately 86% of the technically recoverable shale resources are in the Northeast, Gulf Coast and Southwest regions, which account for 63%, 13% and 10%, respectively, of the total, according to the EIA report, which was released Friday. The report, which was prepared by Arlington, VA-based Intek Inc., noted that the 750 Tcf estimate was a subset of the EIA’s Annual Energy Outlook for 2011, which pegged Lower 48 shale gas resources at 862 Tcf.

Of the three regions, the large shale gas plays are the Marcellus, with 410.3 Tcf, or 55% of total technically recoverable resources; Haynesville, with 74.7 Tcf, or 10% of the total; and Barnett, with 43.4 Tcf, or 6% of the total, it said.

Excluding the Appalachian plays, most notably the Marcellus Shale, the report estimates that only 1-3% of the shale gas resource has been recovered.

Intek estimates that technically recoverable shale oil resources are 23.9 billion bbl in the onshore Lower 48 states. The largest shale oil formation is the Monterey/Santos play in Southern California, which is estimated to hold 15.4 billion bbl, or 64% of the total shale oil resources.

Intek’s estimates for shale gas and shale oil resources are for the undeveloped portions of 20 shale plays that have been discovered in this country.

Production of dry shale gas in the United States rose to 4.8 Tcf in 2010, or 23% of total domestic gas production, from 1 Tcf in 2006. Wet shale gas reserves, which include natural gas liquids, rose to about 60.64 Tcf by year-end 2009, accounting for about 21% of overall domestic gas reserves, the report said.

The 105-page report with tables and charts is available at www.eia.gov/analysis/studies/usshalegas.