EQT Corporation, an integrated energy company, has reported year-end 2010 total natural gas proved reserves of 5,220bcfe, which represents a 28% net increase over the 4,068bcfe the company reported last year.

Proved reserves increased in the Marcellus shale play as a result of wells drilled in 2010, continued improvement in the estimated ultimate recovery (EUR) per Marcellus well, and an increase in the projected number of Marcellus wells to be drilled over the next five years.

Partially offsetting the Marcellus reserve additions was a reduction of Huron and CBM/other proved undeveloped reserves based on an assumption of reduced investments in those plays over the next five years.

The net increase of reserves before production totaled 1,291bcfe, and this increase represents a 928% reserve replacement ratio and resulted from investments of $902m, for a finding and development cost of $0.70 per mcfe.

EQT estimates year-end 2010 total natural gas reserves, including proved, probable and possible reserve categories (3P), at 21.2tcfe, a 70% net increase over 2009.

This increase was driven mainly by the success of EQT’s Marcellus and, to a lesser extent, Huron horizontal drilling programs, the company said.