Paper: Response Of Wasson Levelland Crudes To Nitrogen Carbon Dioxide

Laboratory studies have been made to determine the oil recovery by displacing the Levelland and Wasson crudes by carbon dioxide at various pressures. For the case of the Wasson crude it has been found that a slug of carbon dioxide equal to ten percent of the hydrocarbon pore volume pushed by nitrogen resulted in an oil recovery of 96% of the original oil in place. The use of a slug of carbon dioxide of five percent hydrocarbon pore volume pushed by nitrogen resulted in an oil recovery of 90%. The cost of carbon dioxide brough in from Colorado or New Mexico is expected to be $1.00 to $1.25/MCF. The cost of nitrogen is expected to be less than 50 cents/MCF delivered at high pressure. At Wasson or Levelland reservoir conditions one MCF of nitrogen will occupy three times as much pore space as one MCF of Carbon Dioxide. The cost of nitrogen at reservoir conditions is estimated to be only 15% of the cost of Carbon Dioxide at reservoir conditions. It appears the nitrogen-driven carbon dioxide slug oil-recovery method may have application to various West Texas crudes.