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CONCENTRATIONS (Tables)
12 Months Ended
Dec. 31, 2013
Risks And Uncertainties [Abstract]  
Customers from Whom We Derived 10% or More of Total Oil and Gas Revenue

The following table identifies customers from whom we derived 10% or more of our total oil and gas revenue during the years ended:

 

     December 31,  
     2013     2012     2011  

Conoco, Inc.

     (a     13     28

Phillips 66 Company

     35     18     (a

Shell Trading (US) Company

     33     41     46

 

(a) Less than 10 percent.