Liberian oil quality Offshore-OnshoreAnardarko has discovered high quality oil off the shores of Sierra Leone. Anadarko Petroleum Corporation encountered approximately 114 net feet of light sweet crude oil with a gravity of between 34 and 42 degrees API, with no water contact. An additional 21 net feet of 24-degree gravity crude was encountered in a shallower secondary objective.
Anadarko holds an interest in more than 4.6 million acres on five deepwater blocks offshore Sierra Leone and Liberia, and has identified more than 17 prospects and leads on 3-D seismic on this acreage.
Liberian President Ellen Johnson Sirleaf has stated, "Energy is one of my top priorities, (it) will make a meaningful contribution to economic growth and job creation." "We welcome companies with an excellent record of community and social responsibility."
The American Petroleum Institute gravity, abbreviated API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks. Generally speaking, oil with an API gravity between 40 and 45 commands the highest prices.
Crude oil is classified as light, medium or heavy, according to its measured API gravity.
Light crude oil is defined as having an API gravity higher than 31.1 API.
Medium oil is defined as having an API gravity between 22.3 ?API and 31.1 API.
Heavy oil is defined as having an API gravity below 22.3 API.
Sweet crude oil contains less than 0.5% sulfur. High quality, low sulfur crude oil is commonly used for processing into gasoline and is in high demand, and commands a premium price, particularly in the industrialized nations. "Light sweet crude oil" is the most sought-after version of crude oil. The term "sweet" originated because the low level of sulfur provides the oil with a mildly sweet taste and pleasant smell. Nineteenth century prospectors would taste and smell small quantities of the oil to determine its quality
Light crude oil is liquid petroleum that has a low density and flows freely at room temperature. It has a low viscosity, low specific gravity and high API gravity due to the presence of a high proportion of light hydrocarbon fractions. It generally has a low wax content. Light crude oil receives a higher price than heavy crude oil on commodity markets because it produces a higher percentage of gasoline and diesel fuel when converted into products by an oil refinery.
Light oil is also less expensive to produce because it flows easily to the surface when a well is drilled into the formation.
OIL SEEPS: A TOOL FOR HYDROCARBON EXPLORATION Giuseppe Etiope Istituto Nazionale di Geofisica e Vulcanologia, Roma. Petroleum seeps have historically been important drivers of global petroleum exploration and even today they still can serve as direct indicators of oil subsurface accumulations. Surface macro-seeps, visible oil leaks from the soil or rock outcrops, are generally an indication of a fault in an active Petroleum Seepage System (Abrams, 1995) belonging to a Total Petroleum System.
Historically, offshore drilling has shown that known coastal oil- and gas-producing trends continue out into the ocean and contain similar types of hydrocarbons. The reverse is true. If a known offshore hydrocarbon field exists, and seismic surveys show similar fields extending onshore along with additional indications, such as oil seeps, then the offshore field probably extends onshore. That means that the on shore Liberian deposits could also contain the highly sought after low sulfur light crude that has been found offshore.