HEAVY BASE OIL

Heavy oil is defined as liquid petroleum with a viscosity of more than 200 cp or less than 20°API gravity under reservoir conditions. Although the requirements of less than 12°API gravity and greater than 10,000 cp are occasionally used to identify oil sands (also known as tar sands), there is no formal distinction made between heavy oil and oil sands (tar sands). Under the current reservoir conditions, oil in oil sands is an immobile fluid, while heavy oils are somewhat mobile fluids under naturally occurring pressure gradients. Unconsolidated sandstones (UCSS) are sandstones (or sands) that lack genuine tensile strength due to mineral cementation occurring between the grains of the sandstone. Unconsolidated sandstones are home to several heavy oil reserves.