How Does Deep Sea Drilling Work?

Natural gas like crude oil can be obtained from below the ocean floor. The demand for fossil fuels and natural gas is at all-time high. Because the oceans end up covering a lot of the earth’s area, it is only natural that these fossil fuels are obtained below the ocean, and as such, petroleum companies need to find ways to extract these reserves in order to get to them and be able to use them. Getting to the reserves at the bottom of the ocean floor is a challenge in itself. Considering the fact that it is not at all easy to drill even on land, this is especially challenging. The question here is how can one drill on the ocean floor, which is bereft of light and then get the extracted fossil fuel from the sea floor to the refinery which is located on land, without messing up the ocean with pollution along the way? One more question that needs to be answered is how can all of this be done on rough seas, with heavy purpose built equipment without risking lives and raking up costs?

To get past these challenges, the petroleum companies have put a ton of money (billions of dollars to be specific) into research and development. In the year 1947, the first ever offshore drilling rig was constructed off the coast of Mexico by a bunch of petroleum companies. Today, the offshore drilling rig has become very common, even operating in rough seas like the North Sea. These rigs are feats of engineering, that go down almost a 1000 metres down into the ocean.

Where is natural gas found though?

Natural gas is typically found under the earth at depths of around 500 to 25000 feet along with petroleum deposits. These deposits cannot just be detected willy nilly, but are detected after careful study by geologists who map the ocean surface using techniques like seismic surveying and magnetic surveying. When the surveys give out a positive sign, permits are obtained and exploratory drilling commences in order to prove the gas field. When there is good hints as to the viability of the well and once the studies have estimated the amount of oil and gas available in the field, the drilling can commence. Using a specially designed drill bit, the well is drilled on the surface of the ocean. Using the drilling mud that is generated as a lubricant for the drill bit, the drill is sunk in deeper into the ocean. The process happens in many stages, and after each stage, metal casing is sunk into the hole that seals out the walls of the drilled hole, so that leaks don’t happen. Because the natural gas and petroleum are highly pressurised, the drilling process takes care to seal up the well properly, so that they can be slowly released to the surface. The extracted natural gas can fall into two categories, with one being wet and the other being dry. The wet natural gas needs to be processed further before it can be used as it will be contaminated with other liquids, but the dry natural gas can be used directly.