Just how many Barnett Shale drilling leases have been filed in Tarrant County so far this year? Evidently, according to data that has been compiled, lots and lots of leases have been filed.

The newly updated research shows that the number of leases filed from Jan. 1, 2007 to March 1 of this year totals 342,503.

Prior research shows a total of 35,306 Barnett leases were filed in the years 1997 through 2006, with 23,110 of these in 2006.

The leasing frenzy peaked in the spring and summer of 2008, a period of skyrocketing natural gas prices. The peak month was May 2008, when 18,198 leases were filed at the county clerk's office. Gas futures prices topped $13.50 per million British thermal units that summer.

Contrastingly, this year there were only 3,948 leases filed in January and 2,147 in February. Many of those leases may be for properties for which a prior lease expired as a result of not having a well drilled on it because of low gas prices. Gas futures prices are currently below $4.