Journal of Canadian Petroleum Technology, Vol.42, No.3, 21-28, 2003
A case study of foamy oil recovery in the Patos-Marinza reservoir, Driza sand, Albania
With a current recovery of only 5%, Albania's largest oilfield, Patos-Marinza, (first commercially produced in 1939) still contains potentially more than 199 MMbbl of reserved of 10 to 12degrees API oil at a depth of 1,600 m. A consortium consisting of Albpetrol Albania, Preussag Energie (Germany), Premier Oil (Britain), and the IFC (the private sector arm of the World Bank) are making plans to improve oil recovery in the area. Test wells producing 1 to 2 m(3)/d yielded large rate improvements to over 30 m(3)/d using "progressive cavity pumps" up to 30 m(3)/d with producing sand cuts around 10 to 35%. PVT analysis of the oil, with a relatively high solution GOR of 31 m(3)/m(3), shows a strong tendency to foam (gas in microbubbles without forming a continuous gas phase) below the bubble point, near the initial reservoir pressure. Core tests with different depletion rates resulted in primary oil recoveries of greater than 30%. This paper discussed the detailed suite of laboratory measurements used to examine the Driza crude oil, in the context of present theories of foamy oil and cold heavy oil production with sand (CHOPS).