V
Viscosity
It is the degree of resistance a liquid has to flow. Higher viscosity means greater resistance to flow. Viscosity is affected by temperature, decreasing as temperature increases. It is determined using special viscometers and is expressed in Seconds Saybolt Universal (SSU), Seconds Saybolt Furol (SSF), and centistokes.
Viscosity is important in the injection of fuels into engines and burners. It is also critical in pumping crude oil and products by pipeline. A higher viscosity than that considered in the design will reduce the desired flow and will require greater power in the motor of the pumps.
Viscosity also affects the factors of the measuring instruments, falsifying the readings.
Volatility
It is the measure of how easily a product vaporizes. Volatile products have high vapor pressure and a low boiling point. It is measured using the ASTM D86 test and is expressed in degrees of temperature at which certain volumes distill.
W
West Texas Intermediate
It is the crude oil produced in Texas, United States, and serves as an international price benchmark. ENAP uses it as a reference to calculate import parity prices. It is known by the abbreviation WTI and was originally selected in 1983 as the primary reference by the New York Mercantile Exchange (Nymex), where crude oil futures contracts are traded. Unlike Brent Dated, which is a crude oil with broad geographical coverage, WTI is produced for domestic consumption in the United States. However, it serves as a reference for most South American export crudes.