by Jerry Mooney
Oil and gas are two of the world’s most sought-after resources. Research shows they help provide more than 50 percent of energy needs worldwide. They help burn electrical current, power transportation by air, land, and sea, and manufacture plastic, road oil, synthetic materials, asphalt, and chemicals.
Gas comes in liquid and solid forms and lies at the bottom of some of the world’s oceans. Offshore exploration is the driving force to tap into these resources. Offshore drilling companies invest billions of dollars in labor and equipment each year to mine for these valuable fuels.
Here Is How It Works
Offshore drilling utilizes several conventional and unconventional resources to help extract the oils. At the same time, they also try to protect the marine environment from pollution and other hazards.
Offshore drilling is the process of boring holes in the ocean floor to extract gas and oil. When companies locate a potential site, they start by installing high-tech drilling equipment and machines to drill wells on the ocean bed. Three primary drilling phases enable companies to extract natural gas and oil from the ocean floor.
Spudding
At this stage, a mobile drilling unit drills a hole and installs a casing, usually around 36 inches, about 100 meters in the sea bed. This sets up the base for the next phase of the drilling process. From this foundation, they continue to drill smaller holes and install lower casings to stabilize the hole from caving in as they dig.
Installing the Blow out Preventer
When the casings are securely in place, they then erect a guide base or wellhead directly above the casing on the sea bed. They then let down the Blow out Preventer, and Marine Riserto further facilitate the drilling process. These form a connecting point from the drilling deck to the mobile drilling post and into the well for further exploration.
Drilling
When each drilling phase is done, the turntables, pipes, collars and drill bits on the unit work under pressure and in tandem, to start digging. The equipment breaks through ocean rocks and drill wells to allow the gas and oil to flow into the casings. From there, they continue to travel up to the receptacles on the drilling platforms.
How Drilling Platforms Work
Drilling platforms are set up to ensure everything is in place for the drilling crew to extract the oil from beneath the sea. Some types of platforms can include:
Floating production platforms
These can drill down to almost 6,000 feet in the ocean. They may utilize drillships or floating submersible platforms that attach the drilling equipment onto the seabed. It then pumps the oil or gas through flexible risers into the receptacles on the water surface.
The crew also relies on Dynamic Positioning Systems or anchors to keep the ship or platform in place.
Fixed drilling Platforms
Fixed drilling platforms stand on concrete bases and remain in position by the force of their weight above them. They are highly-stable platforms that stay underwater at up to 1,500 feet or sometimes less.
Jack-up platforms
They are a type of drilling barge that forces up to 4 huge pipes or legs into the bottom of the ocean. It then raises the platform on the surface of the water. The legs help keep the platform from shifting in the wind and waves, as drilling progresses.
Drillships
These are typical vessels with drilling equipment in the center. They drill in intense and sturdy ocean currents. The platforms work by sending drill strings to the ocean bed through a type of moon hole. Drillships also depend on satellite sensors and imaging to monitor the drilling site activity.
From this information, the crew then employs electronic motors underneath the hull to propel the ship to keep it in line with the oil well.
Submersible Rig Platforms
They are more suitable for shallow waters. They utilize a combination of jack-up and drilling barges. However, they also employ a series of stilts elevated at high levels to hold the platform in position. The drilling crew then allows the barge to sink to stabilize it.
The barge drops to the bottom of the sea, while the platform stays in place on the raised stilts. When the crew is ready to move to another drilling site, they let the water out, and the barge floats up to the surface, forcing the stilts into the air.
Spar Drilling Platforms
Spar drilling platforms can dig holes close to 10,000 feet. The platform rests above a long, colossal tunnel. The other end of the hull goes close to 700 feet down. The tube suspends above the seabed, and the force of its weight keeps it in position.
The drilling string is let down to the ocean floor through a series of line trails and sturdy cables from the cylinder.
Semi-submersible Rig Platforms
They are similar to submergible rigs but are more suitable for drilling in deep waters. The barge works by letting in enough water, which forces it to the level it needs to start working. The heaviness of the lower hull helps to keep the platform stable by employing large anchors for additional support.
Compliant tower platforms
The design consists of streamlined, steel and concrete towers that can withstand the rigors of hurricanes, high winds, and rough waves. They resemble regular skyscrapers that operate in waters from 1,500 to 3, 00 feet deep.
Seastar drilling platforms
This type of platform is an upgrade to the semi-submersible variety. They rest on a high, submersible hull within the tower. Tension legs support the structure on the ocean bed when the lower hull takes in water and pushes it onto the ocean floor.
The platforms also consist of long, cylinders that stay securely in place to help reduce bobbing up and down with the movement of the wind and waves. The tension legs also sway slightly to each side to help cushion the motion. The platforms operate from between 500 to 3,500 feet and are more suitable for exploring in deep waters with small oil reserves.
Conclusion
Offshore exploration is a highly-technical, expensive, and risky venture. It utilizes a range of conventional and unconventional resources that help extract the oil and gas reserves form the bottom of the ocean.
