Crude Oil Resources
Another word for crude oil is petroleum (from Latin, petra meaning rock, and oleum meaning oil). Petroleum is an organic substance derived from the remains of prehistoric animal and plants. Millions of years ago, rains washed these prehistoric plants and animals into the seas along with sand and silt, which settled on the sea bottom. The increasing pressure and temperature changed the organic materials into petroleum and the mud, silt and sand into rocks.
Petroleum is found in porous rock formations deep under ground in “reserves”, or fields of porous rock formation containing petroleum. Reserves differ greatly in size and accessibility. The Middle East contains world’s largest “proven reserves”, or explored fields where drilling is feasible. At the end of 2005, the Middle East had approximately 62 percent of the world’s proven reserves.
Oil companies extract petroleum via offshore or onshore drilling. Offshore drilling denotes processes whereby oil is extracted from the ocean floor out at sea. Geologists and engineers explore a selected area by studying rock samples from the earth. Measurements are taken, and, if the site seems promising, drilling begins. However, not all drilling sites will necessarily produce oil, and the process is extremely costly. Drilling expenses for a single well can range from $0.5 million for shallow onshore wells to over $25 million for tests in deep water offshore.
In general, the process of leasing, evaluating, drilling and developing an oil or natural gas field typically takes five to ten years. Some fields come online sooner. Others are delayed by permitting or regulatory delays or constraints in the availability of data acquisition and drilling equipment and crews. Large projects and those in deep water may require a decade or more to ramp up to full production.
Once petroleum is extracted, it is taken to an oil refinery, where the hydrocarbon mixture is separated into different materials for a variety of uses by a process known as distillation. For example, several fuels are derived from petroleum, such as ethane, diesel fuel, fuel oils, gasoline, jet fuel, kerosene and liquid petroleum gas. Certain types of resultant hydrocarbons may be mixed with other non-hydrocarbons in order to create several types of end products, like lubricants, wax, asphalt and alkenes (which can be manufactured into plastics).