U.S. Navy Ship Salvage Manual Volume 6 - Oil Spill Response

S0300-A6-MAN-060F-3 GENERAL CHARACTERISTICS OF PETROLEUM BY PRODUCING REGIONThe major petroleum reserves of the world are found in North and South America, the PersianGulf area of the Middle East, the Caspian Sea region, North Africa, the North Sea and to a lesserdegree, continental Europe and the Malayan region.F-3.1 North America. The main oil-producing areas of North America have been the Appalachianregion (Pennsylvania), the Mid-Continent, the Gulf Coast, California, the Rocky Mountainarea, Mexico, Michigan, certain areas of Canada and the North Slope of Alaska.F-3.1.1 Pennsylvania. The so-called “Pennsylvania” crude, produced from wells in certain areasof Pennsylvania, West Virginia and New York, is a classic paraffin-based petroleum. As the firstcrude oil produced in quantity, it has become a basis for comparison. Pennsylvania crude is generallylight in color, with specific gravity of about 0.81. The crude is virtually free of asphaltic constituentswith only traces of sulfur and nitrogen. Gasoline and kerosene fractions may account forup to 60 percent of the volume. The heavy fractions and residuals yield paraffin, petrolatum waxand lubricating oils with relatively flat temperature-viscosity curves and high boiling points.Pennsylvania crude accounts for only a small portion of U.S. production, but the oil continues tobe commercially important because of the high quality of lubricants derived from it.F-3.1.2 Mid-Continent. Mid-Continent crudes are usually darker and heavier than Pennsylvaniacrude, with higher asphalt and sulfur contents. Specific gravity ranges from 0.81 to 0.93. Sulfurcontent is generally about 0.5 percent, although sulfur contents of 1.0 to 1.5 percent are notuncommon in West Texas and Arkansas crudes. Most of the crude produced can be classed asmixed base, although relatively paraffinic or naphthenic oils can be identified. Oil from the Oklahoma-Kansasarea, considered the classical Mid-Continent crude, are typically high in gasolinecontent (25 to 40 percent), relatively low in sulfur (0.2 to 0.4 percent) and very asphaltic. TheKansas crudes are higher in sulfur and less paraffinic; the northern, central eastern Texas oils arelower in sulfur and more paraffinic. West Texas and Texas Panhandle crudes are typically high insulfur (up to 1.5 percent) and of intermediate base, although West Texas crude from deep (Ordovician)formations is very similar to Pennsylvania crude.F-3.1.3 Gulf Coast. Gulf Coast crudes are heavy oils of intermediate to naphthenic base, withlow gasoline content, little or no wax content and high yields of naphthenic lubricating oils. Theheavy fractions and residuals are often asphaltic. Deeper formations often yield lighter oils withhigher gasoline content and lower sulfur content.F-3.1.4 California. The typical California crude, produced in the San Joaquin Valley, is heavy(specific gravity around 0.934), low in gasoline and wax content and high in asphalt content. Thegasoline has a high octane rating because of a large naphthene content. The Los Angeles area producesa lighter, more paraffinic crude (specific gravity around 0.834), although it still containsasphalt. Gasoline content may be as high as 35 percent and kerosene as high as 15 percent. Insome cases, sulfur content may be as low as 0.06 percent. The coastal area north and west of LosAngeles produces oil with qualities between those of Los Angeles and San Joaquin crudes, exceptthat sulfur content is very high—sometimes 2 to 4 percent.F-8