Oil drilling is classified into two main categories: offshore and onshore drilling. The location of the drilling is the most obvious difference, but the two categories are vary in different areas, including cost, profits, time duration for drilling and processes. Both types of drilling have certain advantages over the other, but both are actively used to extract oil to meet the levels of popularity of the world.
As the name recommends, this type of oil drilling takes place off the shore in ocean waters. About 30% of the global oil production comes from offshore drilling.
Drilling an offshore well is similar to the onshore process, initially well is drilled and concrete lines the hole. The oil is pumped up out of the hole using different systems depending on the specific type of platform used for the operation.
For shallow water drilling fixed platform anchored to the ocean floor. To carry the oil to the surface, rigid tubes connect the wellhead to the platform. Deep water drilling requires a floating platform that uses flexible risers for the movement. For extraction of oil, the setup includes risers used to push water and gas down. Other risers extract the oil from water. The risers are designed to keep the oil warm because of the temperature of the water, so it continues flowing freely.
Once pumped, the oil is stored or sent directly to the shore through pipelines, depending on the setup.
Onshore oil drilling:
Onshore drilling encompasses all of the drilling sites located on dry land. Onshore drilling accounts for 70% of the worldwide oil production.
Onshore oil production requires the drilling of deep holes down into the earth’s surface to reach the oil below, Onshore drilling similar like offshore drilling but without the difficulty of deep water between the platform and the oil. Since the ground offers a solid platform, the drilling structures and storage areas are built directly on the soil.
To prevent contamination new well first requires the crew to drill below the water table. Once extraction process begins the hole is then encased in cement to prevent the oil from seeping into the soil or groundwater supply. Based on the specific depth of the oil trap in that area, Drilling continues to the appropriate depth. Once drilling completed, the well uses liquids pumped into the ground at high pressure levels to remove the oil from the rocks.