Trusted Oil Rigging Attorneys

Offshore oil rigs and platforms are large, complex structures designed to drill for, remove, process, and then temporarily store oil or natural gas until the material can be transported for refining and eventual sale. While some rigs are capable of floating or even moving under their own power, others are permanently attached to the sea floor. These structures are usually fitted with living facilities that allow the crew to operate onboard 24 hours a day. Some of the different types of offshore oil rigs include:

• Fixed Platforms – Fixed Platforms are large, permanent structures with legs made of steel and/or concrete. These legs are driven directly into the seafloor. Fixed platforms typically consist of a main deck to support the drilling rig itself along with production facilities and living quarters for the crew.
• Tension Leg Platforms– Tension Leg Platforms, also known as TLPs, are floating structures tethered to the seafloor in order to minimize vertical movement. TLPs are used to drill at depths of up to 6,000 feet.
• Compliant Towers– Compliant Towers are slender, flexible steel structures designed to support a drilling deck and facilities for production. These towers are designed to function at depths of up to 3,000 feet.
• Semi-Submersibles – Semi-submersibles are platforms fitted with buoyant hulls which allow them to float on water and be easily transported from location to location. Semi-submersibles can be kept stationary during drilling and production either with ropes and chains or through the use of dynamic positioning technology. These rigs are designed to operate at depths of up to 10,000 feet.
• Spars– Spars are generally secured to the seabed just like Tension Leg Platforms (TLPs), but use ordinary mooring lines as opposed to vertical tension tethers. Some spars can operate at depths up to 8,000 feet. There are three types of spars, including:
  • Conventional Spar– a one-piece unit designed with a cylindrical hull.
  • Truss Spar– a multi-piece design that features an upper buoyant hull called the “hard tank” connected to the bottom, ballasted soft tank by a number of trusses.
  • Cell Spar– a platform constructed from several vertical cylinders.
• Drillships– Drillships are ocean-going vessels designed with drilling rigs onboard. These ships are often used to explore for oil and gas in deep water or as platforms for scientific research. While exploring, these maritime vessels are kept in place through the use of dynamic positioning technology. Drillships can operate at depths of up to 12,000 feet.
• Floating Production, Storage and Offloading Systems–  Floating Production, Storage and Offloading Systems, also known as FPSOs, are large single-hulled structures often shaped like a ship. FPSOs house processing facilities for oil and gas that is produced by production platforms. They are typically moored to specific locations for long periods of time.
• Jack-Up Rigs– Jack-up rigs, also known as Mobile Offshore Drilling Units (MODUs), are moveable platforms fitted with legs that can be lowered to the seabed in order to lift the rig above the water. Jack-up rigs can function at depths of up to 550 feet.