EBITDAX (non-GAAP) for fourth quarter 2012 was $20.6 million, or $0.53 per diluted share, compared to $22.8 million, or $0.74 per diluted share, for fourth quarter 2011. See “Supplemental Non-GAAP Financial and Other Measures” below for our reconciliation of EBITDAX to net (loss) income.
Average realized commodity prices for fourth quarter 2012, before the effect of commodity derivatives, were $78.27 per Bbl of oil, $30.27 per Bbl of NGLs and $3.22 per Mcf of natural gas, compared to $85.56 per Bbl of oil, $51.71 per Bbl of NGLs and $3.19 per Mcf of natural gas for fourth quarter 2011. Our average realized price, including the effect of commodity derivatives, was $44.50 per Boe for fourth quarter 2012, down 12% compared to $50.63 per Boe for fourth quarter 2011.
Lease operating expenses increased in fourth quarter 2012 compared to fourth quarter 2011 primarily due to higher workover, compression, water hauling, well repair and maintenance expenses. We expect lease operating expense per Boe to decrease in 2013 due to cost savings from our new infrastructure projects and higher production. Production and ad valorem taxes increased due to our increase in oil, NGL and gas sales. General and administrative expenses increased primarily due to higher share-based compensation as well as salaries and benefits, a result of increased staffing. Depletion, depreciation and amortization expense increased primarily due to higher production and oil and gas property carrying costs, relative to estimated proved developed reserves. Higher oil and gas property carrying costs primarily reflect our development of our oil-focused Wolfcamp shale play.
2012 Estimated Proved ReservesYear-end 2012 proved reserves totaled 95.5 MMBoe, up 24% from year-end 2011 proved reserves of 77.0 MMBoe. The Company’s proved oil reserves increased 106% to 37.3 MMBbls, compared to year-end 2011 proved oil reserves of 18.1 MMBbls. Year-end 2012 proved reserves were 39% oil, 30% NGLs and 31% natural gas and 34% proved developed, compared to 23% oil, 38% NGLs and 39% natural gas and 44% proved developed at year end 2011. At December 31, 2012, 99.9% of our proved reserves were located in our core operating area in the Permian Basin.