Deep water

Drill ships are used in deep water and remote areas, and these vessels are equipped with a drilling unit positioned in the middle of the ship. Positioning is achieved dynamically by computer controlled thrusters. The ample storage space allows operation for long periods of time without re-supply. 

Steel piled jackets are the most common type of platform and are employed in a wide range of sea conditions, from the comparative calm of the South China Sea to the hostile Northern North Sea. Steel jackets are used in water depths of up to 150 metres and may support production facilities a further 50 metres above mean sea level. In deep water all the process and support facilities are normally supported on a single jacket, but in shallow seas it may be cheaper and safer to support drilling, production... 

Tension leg platforms (TLP) are used mainly in deep water where rigid platforms would be both vulnerable to bending stresses and very expensive to construct. A TLP is rather like a semi-submersible rig tethered to the sea bed by jointed legs kept in tension. Tension is maintained by pulling the floating platform down into the sea below its normal displacement level. The legs are secured to a template or anchor points installed on the seabed. 

Deep water disposal Toppling on site Artificial reef... 

The gas reservoirs located ia very deep waters, ia coal beds, and ia tight sands are now more accessible. Fifteen percent of the U.S. gas supply ia 1992 was derived from tight sand formations and 1.4 x 10 of coal-bed methane was added to the proven reserves (22). In 1992, U.S. proven reserves were placed at 4.67 x 10 ia the lower 48 states, and it was estimated that the identified gas resource ia the United States and Canada exceeds 3.4 X 10. Based on the 1992 rate of natural gas consumption, the United States has between 8 and 10 years of proven reserves and a domestic... 

Bioluminescence functions in mating (fireflies, the Bahama fireworm), in the search for prey (angler fish, Photmus fireflies), camouflage (hatchet fish, squid), schooling (euphausiid shrimp), and to aid deep water fish (flashlight fish, Photoblepharon to see in the dark ocean depths. 

Similar deposits of radiolaria or diatoms composed of siUceous skeletal remains are widespread in more temperate areas in deep water below 5000 m. The deposits maybe very pure. The diatoms recovered from deposits on land are used as fillers or filter materials or as a source of high quaUty carbonate or sihca (see Diatomite). 

Sodium chloride has long been used as a shale stabilizer because of low cost, wide availabiUty, and its presence in many subsurface formations. The inhibitive nature of salt muds increases as the salt content increases from seawater to saturated sodium chloride. In addition to the sodium chloride consumed aimuaHy for drilling fluid, considerable quantities are incorporated while drilling salt zones. This material has been used more for minimizing washouts in salt zones than for stabilizing shales. High salt levels have found appHcation in deep water drilling (7). 

In energy extraction, titanium alloys are being used in deep-water hydrocarbon and geothermal weUs for risers. Corrosion resistance, high strength, low modulus (flexible), and low density can result in risers one-fourth the weight and three times the flexibiHty of steel. 

A number of current coupled ocean-atmosphere climate models predict that the overturning of the North Atlantic may decrease somewhat under a future warmer climate.While this is not a feature that coupled models deal with well, its direct impact on the ocean s sequestration of carbon would be to cause a significant decline in the carbon that is stored in the deep water. This is a positive feedback, as oceanic carbon uptake would decline. Flowever, the expansion of area populated by the productive cool water plankton, and the associated decline... 

A more economical alternative is found in a submersible pump where the pump, directly coupled with the prime mover, is slid into the tubewell through narrow pipes. Narrow pipes are easy to sink into rocky terrain or very deep water levels. They are less expensive and are easy to install due to the elimination of the need for a pump house. Once the unit is slid into the well it requires little maintenance. (See Figures 7.5-7.7.) Such pumps have a standard centrifugal multistage arrangement, and the motors are required to work under water or any other liquid. These motors have an exclusive application for submersible pumps. 

Moderate - Thousands of gallons (e.g., a few feet of water on the floor of a typical pump room i. I..arge - Tens of thousands of gallons [e.g., a few feet of water in large rooms, vei-y deep water (more than 10 feet) in a typical pump room]. 

Manor Way, A1014 provides road access to the mainland a rail line for freight nms fmiii the main line through the Shell UK Oil refinery to Thames Haven, and to the Mobil Oil disiribution terminal at Coi-yton. A deep water channel provides access to the ten jetties of the two refineries. The control room and pumping station for the U.K. oil pipeline is located at Coryton. Oil products are transported by pipeline from Texaco Ltd on Canvey Island and from the two oil refineries ou the mainland Helicopters from the site landing pad. survey the pprelines. 

Production of crude oil and natural gas involves technologies that have become increasingly complex as the remaining resources have become more difficult to locate and remove from their subsurface locations. Many new discoveries are made in sediments below the ocean floor in deep-water, and thus require removal of the oil and gas through long water columns. Other situations now require directional drilling of wells so that production involves transfers along wells that arc far from vertical. 

In deep water, it is common to find kick fluids trapped above the blowout preventer stack when the well is shut in. These fluids must be vented through the diverter system. 

The electrodes designed for permanent installation on deep-water structures must be protected from damage but must also correctly view the protected structure. Thus electrodes must be closely placed to the structure to avoid the incorporation of an IR element in the potential measured, but must not create a protection shadow which could cause a false indication of the protection level. 

Another consequence of the effect of pressure on gas solubility is the painful, sometimes fatal, affliction known as the bends. This occurs when a person goes rapidly from deep water (high pressure) to the surface (lower pressure), where gases are less soluble. The rapid decompression causes air, dissolved in blood and other body fluids, to bubble out of solution. These bubbles impair blood circulation and affect nerve impulses. To minimize these effects, deep-sea divers and aquanauts breathe a helium-oxygen mixture rather than compressed air (nitrogen-oxygen). Helium is only about one-third as soluble as nitrogen, and hence much less gas comes out of solution on decompression. 

Tests on plastics in deep water have been extremely successful. As an example filament-wound RP cylinders and PVC buoys retained their strength. PVC washers and the silicone-seating compound used in steel-to-aluminum joints helped prevent their corrosion. Black twisted nylon and polypropylene... 

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