text: Although current market prices have fallen significantly, under SEC guidelines, the commodity prices used in the 31 December 
  2014 reserve estimates were based on the 12-month unweighted arithmetic average of the first day of the month prices for 
  the prior 1 January 2014 through 1 December 2014, adjusted by lease for transportation fees and regional price differentials. 
  For crude oil volumes, the average West Texas Intermediate posted price of $91.48 per barrel used to calculate PV-10 at 31 
  December 2014 was down $1.94 per barrel from the average price of $93.42 per barrel used to calculate PV-10 at 31 December 
  2013. For natural gas volumes, the average Henry Hub spot price of $4.35 per million British thermal units (“MMBTU”) used to 
  calculate PV-10 at 31 December 2014 was up $0.68 per MMBTU from the average price of $3.67 per MMBTU used to calculate 
  PV-10 at 31 December 2013. All prices were held constant throughout the estimated economic life of the properties. 
  
  Summary reserve information based on NSAI SEC Constant Case is provided below. For management’s case reserve report 
  assumptions, see Note 17 for further information. 