Petrohawk Energy Corp. charted 50% pro forma year-over-year reserves growth last year, ending 2010 with 3.4 Tcfe of estimated proved reserves, the company said. Shale plays led the charge, particularly with a 100% increase in production from the Haynesville and Bossier shales and a whopping 235% increase in the Eagle Ford in South Texas.

About 500 Bcfe of Petrohawk reserves were divested last year. Not adjusting for sales, Petrohawk grew reserves 23% year over year.

Full-year 2010 production averaged 675 MMcfe/d (562 MMcfe/d pro forma for property sales, which accounted for about 113 MMcfe/d). The company exited 2010 producing about 744 MMcfe/d compared to a pro forma exit rate of 455 MMcfe/d in 2009.

Net production from the Haynesville and Bossier shales averaged 426 MMcfe/d during 2010, a 100% increase year over year, the company said. Haynesville Shale and Bossier Shale net production was approximately 557 MMcfe/d at year-end 2010, aided by a lesser decline rate due to Petrohawk’s reservoir optimization program. The Eagle Ford Shale also grew at a high rate, with 67 MMcfe/d produced on average, compared to 20 MMcfe/d average net production in 2009, an increase of 235%. At year-end net production from the Eagle Ford Shale was 125 MMcfe/d.

Of the company’s 3.4 Tcfe of proved reserves (92% natural gas), about 1.4 Tcfe was added through the drillbit last year. About 973 Bcfe was added in the Haynesville Shale with 351 wells drilled (101 operated and 250 non operated), 467 Bcfe in the Eagle Ford Shale with 73 wells drilled (68 operated and five non operated), and 14 Bcfe in the Bossier Shale with 16 wells drilled (one operated and 15 non operated).

Production of 562 MMcfe/d, pro forma for approximately 113 MMcfe/d that was divested during the year, represented 70% year -over-year growth. Production before taking asset sales into account averaged 675 MMcfe/d, or 34% growth. Last year about 70% of production was hedged with floors averaging $5.83/MMBtu and $78.31/bbl.

Petrohawk said 2011 production will consist of about 12% crude oil, condensate and natural gas liquids (NGL), compared to 5% of production in 2010. It said about 27% of 2011 oil and gas revenue will be derived from crude oil, condensate and NGLs. The company said it expects to exit 2011 with more than 15% of production from crude oil, condensate and NGLs.

The company set the midpoint of first quarter production guidance at 770 MMcfe/d, which represents 15% pro forma growth over 4Q2010. The midpoint of full-year 2011 production guidance is 885 MMcfe/d, a 31% year-over-year increase and a 57% year-over-year increase pro forma for 2010 divestitures.

For 2010 capital expenditures totaled $2.8 billion. Capital expenditures for 2011 are budgeted at $2.3 billion.