Oil & Gas
What is Oil?
Oil, also called as petroleum, or crude oil, was formed from the remains of tiny sea plants and animals that died millions of years ago. When the plants and animals died, they sank to the bottom of the oceans. Over time, they were buried by thousands of feet of sand and sediment, which turned into sedimentary rock. As the layers increased, they pressed harder and darder on the decayed remains at the bottom. The heat and pressure eventually changed the remains into Oil. It is classified as a nonrenewable energy source because it takes millions of years to form. We cannot make new petroleum reserves in a short period of time.
What is Natural Gas?
Natural gas is a fossil fuel like petroleum and coal. Natural gas is considered a fossil fuel because most scientists believe that it was formed from the remains of ancient sea plants and animals. When the plants and tiny sea animals died, they sank to the bottom of the oceans where they were buried by sediment and sand, which turned into sedimentary rock. The layers of plant and animal matter and sedimentary rock continued to build until the pressure and heat from the earth turned the remains into petroleum and natural gas.
Oil and Natural Gas are buried beneath the earth’s curst, on land and under the oceans. To find it, geologists use their knowledge of land and rock formations, the geologic history of an area, and sophisticated technology. Combining all this information, geologists ar more likely to be successful when they drill.
Drilling (Onshore & OffShore)
To drill a well, large drilling rig is brought to the site. Once it is situated above the desired location, drilling can begin.
Drilling bits have sharp teeth that rotate to tear apart rock while the well is drilled. During the process, mud had to be pumped from the well to the surface, which is very expensive part of drilling. After that, casing, cementing is carried out to complete the drilling well.
Retrieving / Production
Once the well have been completed, they can go into production. Production wells do not have the complex, above ground structures that are in place during drilling. Instead, the wells are capped with smaller units. Ideally, oil is extracted using natural drive, which means there is enough pressure in the well to move the oil and no pumping is needed.
Wells with natural drive have Christmas trees above groud. A Christmas tree, in the petroleum industry, is a series of valves and gauges used to measure and control the flow and pressure of the well.
Other wells do not have enough natural drive to move oil out of the earth. They must use pumps to lift the oil to the surface. Typically, this is done with a sucker-rod pump, sometimes called a horse head pump because of its shape.
Shipping of Crude Oil
Much of the oil we use is shipped via pipeline. Oil pipelines move crude oil from platforms offshore to refineries onshore. Pumping stations along the pipelines are located every 60 to 100 miles to keep the oil flowing.
For longer distances, oil is put in tanker trucks or moved by sea on oil tankers. Curde oil produced in Venezuela, for example, is carried to the U.S. in oil tankers. This is off-loaded at a refinery to be turned into useful products. Oil tankers have hulls, or shells, to help prevent oil spills.
After transportation by oil tanker of pipeline to a refinery, much of the crude oil is placed in storage facilities or tank farms. These large cylinders hold the crude oil unitl the refinery is ready to process it.