Introduction

Fig. 1: Oil rig. (Source: Wikimedia Commons)

Deep-water drilling is the exploration for oil and natural gas deposits beneath the earth's surface through the seabed. Oil platforms are placed in bodies of water and extract and store large amounts of oil or natural gas until brought to shore for refining. Currently in the United States there are 3400 wells in the Gulf of Mexico. The federal offshore oil production in the Gulf of Mexico accounts for 23% of the total US crude oil production. The natural gas production in the Gulf accounts for 7% of the total dry productions in the US. [1]

How It works

Deep well drilling works with many different types of apparatuses. First, using sonic equipment, oil companies will determine where they're most likely to be large oil deposits. Next they will use a MODU (mobile offshore drilling unit) to dig the well and then depending upon the MODU, will produce oil on site or take the deposits onshore to produce. [2] There are four main types of MODUs-first there is a submersible MODU which is a barge that is anchored in the sea floor connected to a large deck above the water that houses the drilling platform. Secondly there are jackup rigs. Jackups rest on floating barges and are brought to the drilling site byway of being towed by another boat. At the sight however, the jackup ejects legs to the seafloor to withstand the tidal motions. There are also drill ships that are giant ships with drilling rigs. Lastly, there are semisubmersible MODUs. They float on top of the ocean above huge submerged pontoons and use many anchors to stabilize their movement. [1] The MODU will then drill into the ocean floor and search for oil deposits. Once a MODU finds oil, it must be sealed in order to protect the surrounding environment and crew. The fluids are sent from the well up to the production deck through risers. [3]

Fig. 2: Map of the BP oil spill as of May 25, 2010. (Source: Wikimedia Commons, courtesy of NOAA.)

Risks

Although effective, deep well drilling comes with a set of risks and drawbacks. First, it is dangerous to drill at such depths because the complexity of the equipment increases significantly. [1] Another risk that comes with drilling at these locations is the harsh offshore environment.

One large risk is the damage that deep-water drilling does to the oceanic environment. Every time that oil is drilled, other minerals are brought up fro the ocean floor. [2] The piping and infrastructure needed to get offshore oil from the deep-water rigs on to land also affect the shore land and coastal environment. [1]

Conclusion

Offshore drilling has become a controversial topic in recent years due to the large oil spill in the Gulf of Mexico in 2010. However coming with a slight list of setbacks, deep well drilling is still done all around the world as it has proven as an effective way to drill for oil.

© Rachel Kalick. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] "Annual Energy Review 2011," U.S. Energy Information Administration, DOD/EIA-0384(2011), September 2012.

[2] "Annual Energy Outlook 2014," U.S. Energy Information Administration, DOE/EIA-0383(2014), April 2014.

[3] W. L. Leffler, R. Pattarozzi, and G. Sterling, Deepwater Petroleum Exploration and Production: A Nontechnical Guide, 2nd Ed. (PennWell Corp., 2011).