LAFAYETTE, La., Jan. 15, 2013 /PRNewswire/ -- Stone Energy Corporation (NYSE: SGY) today announced its estimated year-end 2012 proved reserves were 129 Mmboe (million barrel equivalents) or 773 Bcfe (billion cubic feet of natural gas equivalent), as compared with 100 Mmboe or 602 Bcfe at year-end 2011, representing a 28% increase in its estimated proved reserves. From all sources, Stone replaced approximately 288% of production in 2012. The estimated proved reserves were 35% oil, 14% natural gas liquids (NGLs) and 51% gas on an equivalent basis. The changes from 2011 year-end estimated proved reserves to 2012 year-end estimated proved reserves included production of approximately 15 Mmboe or 91 Bcfe, drilling additions/extensions of 30 Mmboe or 181 Bcfe, net upward revisions of 7 Mmboe or 44 Bcfe and net acquisitions of 6 Mmboe or 37 Bcfe. The present value of the estimated future net cash flows from estimated proved reserves before income taxes, using a 10% discount rate (PV10), was approximately $2.0 billion using 12 month average prices after differentials of $101.20 per barrel of oil, $38.23 per barrel of NGLs and $2.68 per Mmbtu of gas. The estimated year-end 2012 proved reserves included proved developed (PD) reserves of 73 Mmboe or 437 Bcfe (split 40% oil, 12% NGLs, 48% gas) and proved undeveloped (PUD) reserves of 56 Mmboe or 337 Bcfe (split 28% oil, 17% NGLs, 55% gas). In addition, there were 59 Mmboe or 356 Bcfe of estimated probable reserves and 167 Mmboe or 1.0 Tcfe of estimated possible reserves at year-end 2012. All of Stone's 2012 year-end estimated proved, probable and possible reserves were independently engineered by Netherland Sewell & Associates. Chairman, President and Chief Executive Officer David Welch stated, "We are very pleased with our third consecutive year of reserve growth in 2012. Our strategy of investing in price advantaged natural gas and material oil projects is paying off in this low natural gas price environment. Our programs in Appalachia, deep water and deep gas all generated increased reserve volumes for the year. Our reserves mix is now 44% Appalachia, 34% Deep Water, and 22% Conventional Shelf/Deep Gas, confirming our diversification strategy. Our reserve life has grown from 5.2 years in 2009 to approximately 8.5 years currently. Stone is a very different company from several years ago in its asset balance and its exciting opportunity set." Production guidance for the fourth quarter of 2012 of 42,500 - 45,000 Boe per day (255-270 Mmcfe per day) is confirmed towards the upper end of the range. Production guidance for 2013 remains at 41,000 - 44,000 Boe per day (245-265 Mmcfe per day) as projected production from the La Cantera #3 well in the third quarter is expected to offset lost production during the first quarter from Stone's Mary field in Appalachia. The Mary field has been shut-in since late December due to a third party pipeline repair issue. The pipeline impacts approximately 50 Mmcfe per day and is expected to be repaired before the end of the month.