You may be aware of the fact that all the oil is accessible either on land or in shallow water. You also can find oil deposits, which are buried deep under the ocean bed. Oil rigs do the job of reaching out to those oil deposits.
But they have to take extra safety precautions for that. The whole process has to be operated properly. Otherwise, it can be deadly both for the surrounding environment and oil workers.
How Do Offshore Oil Rigs Function
For determining the drilling sites for producing oil, oil companies use sonic equipment. After that, in order to dig the initial well, they use a MODU or mobile offshore drilling unit. Some of these units are converted into production rigs.
That means, after finding the oil deposits, they switch from drilling for oil to capturing the oil also. Most of the time, after finding the oil deposits, most of the companies replace the MODU with a more permanent and equipped oil-producing rig for capturing the oil.
The whole process of oil drilling and capturing requires a lot of high-end equipment for different purposes. For screening the sand from the collected oil capturing, companies require sand control screens from a premium mesh screen manufacturer.
Types Of MODU
Here are the different types of MODUs that are being used in oil drilling. And they are,
- Submersible MODU.
- Jackup.
- Drill ships.
- Semisubmersibles.
Continuation Of The Function
The job of MODU is to drill down deep into the ocean bed in order to find oil deposits. The particular part that extends below the deck and goes through the water is called the riser. The purpose of this riser is to let the drilling fluids flow between the ocean bed and the rig.
Now what engineers do, they lower a drill string through the riser. In case you are wondering what this drilling string is. It is basically a series of pipes, which is designed for drilling down to the oil deposits.
At the sea bed, there is the BOP or blowout preventer. It comes with a pair of clamps that are hydraulically powered. It has the capability to close off the pipe, which is leading up to the rig, if any blowout occurs.
As the rig starts drilling down, the engineers have to add more pipe to the drill string. Every section of pipe has a length of around 30 feet or 9.1 meters.
How Do Engineers add Stability?
For adding stability to the well, the engineers implement metal casing. It is similar to those land-based oil rigs. These casings prevent the well from collapsing in on itself. Every casing is properly lined with cement walls.
As the well gets deeper, the casings get narrower. As the depth of the well increases, oil companies start to use drill bits, which are progressively smaller. At every annulus, for sealing the two sections together, engineers utilize a liner hanger O-ring.
What is this annulus? This is the particular spot where the narrow casing joins with the wider one.
In order to make it ready for a production rig, the engineers have to seal the well once the MODU hits the oil. For sealing off the wellbore, the engineers usually use a pair of plugs. Near the oil deposits, the bottom plug fits.
During the time the engineers are placing the top plugin in order to cap the oil well, seawater, or drilling mud offers the pressure for holding the plugin in the proper place. Now, the well is absolutely ready for a production rig to be taken over.
Conclusion
The working of an offshore production rig is quite similar to a land-based oil rig. So, these are the whole function of offshore oil drilling. The whole process involves a lot of danger and environmental hazards. The engineers have to follow the safety protocols in a proper way.
