Estimates of Original Oil-in-Place
A comprehensive study by Petroleos de Venezuela S.A. (PDVSA) established the magnitude of the original oil-in-place (OOIP) at 1,180 billion barrels of oil (BBO), a commonly cited estimate for the Orinoco Oil Belt (Fiorillo, 1987); PDVSA recently revised this value to more than 1,300 BBO (Gonzalez and others, 2006). In this study the median OOIP was estimated at 1,300 BBO and the maximum at 1,400 BBO. The minimum OOIP was estimated at 900 BBO, given the uncertainty of regional sandstone distribution and oil saturation (Fiorillo, 1987).
Estimates of Recovery Factor
Recovery factor, or that percentage of the OOIP that is determined to be technically recoverable, was estimated from what is currently known of the technology for recovery of heavy oil in the Orinoco Oil Belt AU and in other areas, particularly California, west Texas, and western Canada. The minimum recovery factor was estimated to be 15 percent, the recovery expected for cold production using horizontal wells. The median recovery factor was estimated to be 45 percent, on the assumption that horizontal drilling and thermal recovery methods might be widely used. The maximum recovery factor was estimated to be 70 percent, on the assumption that other recovery processes, in addition to horizontal drilling and steam-assisted gravity drainage, might eventually be applied on a large scale in the Orinoco Oil Belt AU.
The assessment of technically recoverable heavy oil and associated gas resources is shown in table 2. The mean of the distribution of heavy oil resources is about 513 BBO, with a range from 380 to about 652 BBO. The mean estimate of associated dissolved-gas resource is 135 trillion cubic feet of gas (TCFG), with a range from 53 to 262 TCFG. No attempt was made in this study to estimate either economically recoverable
2. North Dakota raised its forecast for oil output on growth in and around the Bakken Shale formation There is another 100,000 barrels a day in north Dakota from oil that is not in the Bakken.
Output may reach 300,000 to 400,000 barrels a day by mid- 2011 and stay at that level for 10 to 15 years, said Lynn Helms, director of the North Dakota Mineral Resources Department. The state’s previous estimate was 220,000 to 280,000.
The forecast was raised on discoveries by companies such as Continental Resources Inc., Helms said in an interview. Drilling advances are enabling producers to tap the Bakken, where rocks lack the porosity and permeability of conventional oil fields. The Bakken contributed to last year’s 7.5 percent gain in U.S. crude output, the biggest since 1955 and the first in 18 years. The Energy Department forecast a 1.8 percent increase in 2010.
The top end of North Dakota’s production projection would represent more than 7 percent of nationwide oil output