Major Customers	12 Months Ended
Dec. 31, 2013
Major Customers
Major Customers	4. Major Customers The Partnership sells crude oil and natural gas on credit terms to refiners, pipelines, marketers, and other users of petroleum commodities. Revenues are received directly from these parties or, in certain circumstances, paid to the operator of the property who disburses to the Partnership its percentage share of the revenues. During the year ended December 31, 2013, one operator and one marketer accounted for 54.8% and 40.9% of the Partnership’s crude oil and natural gas revenues, respectively. During the year ended December 31, 2012, one operator and one marketer accounted for 79.9% and 14.4% of the Partnership’s crude oil and natural gas revenues, respectively. During the year ended December 31, 2011, one operator and one marketer accounted for 63.9% and 27.5% of the Partnership’s crude oil and natural gas revenues, respectively. Due to the competitive nature of the market for purchase of crude oil and natural gas, the Partnership does not believe that the loss of any particular purchaser would have a material adverse impact on the Partnership.

4. Major Customers

The Partnership sells crude oil and natural gas on credit terms to refiners, pipelines, marketers, and other users of petroleum commodities. Revenues are received directly from these parties or, in certain circumstances, paid to the operator of the property who disburses to the Partnership its percentage share of the revenues. During the year ended December 31, 2013, one operator and one marketer accounted for 54.8% and 40.9% of the Partnership’s crude oil and natural gas revenues, respectively. During the year ended December 31, 2012, one operator and one marketer accounted for 79.9% and 14.4% of the Partnership’s crude oil and natural gas revenues, respectively. During the year ended December 31, 2011, one operator and one marketer accounted for 63.9% and 27.5% of the Partnership’s crude oil and natural gas revenues, respectively. Due to the competitive nature of the market for purchase of crude oil and natural gas, the Partnership does not believe that the loss of any particular purchaser would have a material adverse impact on the Partnership.