Offshoring areas

Hydrocarbons are of a lower density than formation water. Thus, if no mechanism is in place to stop their upward migration they will eventually seep to the surface. On seabed surveys in some offshore areas we can detect crater like features ( pock marks ) which also bear witness to the escape of oil and gas to the surface. It is assumed that throughout the geologic past vast quantities of hydrocarbons have been lost in this manner from sedimentary basins. 

Product quality is not limited to oil and gas quality certain effluent streams will also have to meet a legal specification. For example, in disposal of oil in water, the legislation in many offshore areas demands less than 40 ppm (parts per million) of oil in water for disposal into the sea. In the UK, oil production platforms are allowed to flare gas up to a legal limit. 

This is largely due to the discovery and development of major natural gas fields in the U.S. Southwest, mid-contment, on- and offshore areas of the Gulf of Mexico and Canada—and the development of safe and efficient interstate natural gas trans-missiou pipelines to transport natural gas to markets across the country. Some 77 percent at the natural gas consumers use is produced domestically. 

It is common in many offshore areas to encounter a shallow gas hazard. Quite often, these hazards can be spotted on seismic, and a surface location is chosen to avoid the hazard. However, there is always a risk of encountering a shallow gas flow with insufficient casing in the well to allow a shut-in. In this instance a diverter system is called on as a safety measure. The ideal function of the diverter system is to allow the well to flow and subside by natural means. In many cases the diverter system simply provides enough time to evacuate the rig. 

A key factor in the C02 capture and storage system is the need for a functioning transportation system for the C02 captured at energy conversion units. The transport options suitable for the quantities produced by large power stations or industrial plants would mainly be pipeline transport for onshore distances and ship transport for the offshore area.6... 

First oil and gas lease sale in federal offshore area held through 1984, more than 100 such sales had been held, resulting in the leasing of some 38 million acres (4 percent of the federal offshore area), and federal revenues from that leasing had exceeded 77 billion. 

Anderson, G. C., and R. R Zeutschel. 1970. Release of dissolved organic matter by marine phytoplankton in coastal and offshore areas of the northeast Pacific Ocean. Limnology and Oceanography 15 402-407. 

As a result of such extensive use of agricultural and industrial chemicals and uncontrolled production of wastes the entire Indian environment and biota such as its atmosphere (Ramesh et al., 1989), freshwater sources (Pillai, 1986 Rehana et al., 1996 Babu Rajendran and Subramanian, 1997), estuaries (Bhattacharya et al., 2003), coastal and offshore areas (Sarkar and Sen gupta, 1988a,b Iwata et al., 1993a Sarkar et al., 1997), inland soils (Kawano et al., 1992), fish (Babu Rajendran et al., 1992, 1994 Das et al., 2002), birds (Tanabe et al., 1998a), bats (Senthilkumar et al., 1999b), river dolphins (Kannan et al., 1993, 1994 Senthilkumar et al., 1999a Subramanian et al., 1999), food stuff (Kannan et al., 1992) marine mammals (Tanabe, 2002 Tanabe et al., 1993) and human milk (Tanabe et al., 1990) have been reported to be loaded with multitude of mixtures of POPs. 

A comparison of the data from the different expeditions clearly showed that, for surface waters, Cd, Cu, Ni and, to a lesser extent, Cr and Fe concentrations were higher in nearshore than in offshore areas. A possible explanation was that the main contribution to the increase in the metal concentrations close to the shore might be due to the particulate matter included in the Antarctic pack ice and then transferred to the sea during the melt. To verify this hypothesis in the 1990 1991 and 1991-1992 expeditions some preliminary sampling in the presence and absence of pack were conducted, but the number of samples and the relative data were inconclusive (20). So, in 1993-1994, only one station was chosen at the Wood Bay (Figure 8.2) and both dissolved and particulate metals were determined to obtain detailed data along a single water column (22). 

Sea of Bothnia The southern half of the offshore area of the Sea of Bothnia remains ice-free in mild winters (about 34% of winters in the considered range) except for a very narrow strip of ice off the Swedish coastal fast ice and a wide belt of ice off the Finnish archipelagos. In all other winters, drift ice increasing in density toward the north is to be expected throughout the offshore waters. In severe winter seasons (about 16% of winters), the compact drift ice in the entire sea area freezes together, in normal winters only in the northern third. 

In the offshore areas, initial ice normally forms in December, at the northern periphery in the first decade, and at the southern periphery in the third decade. The coastal area of the Bay of Bothnia is normally ice-free again by the second decade of May. After a severe winter, the ice lasts until the first decade of June almost in the entire area. On average, 130-180 days of ice is to be expected in the coastal waters, and in extremely cold winters as many as 175-215 days. 

Lake Pontchartraln is a shallow, open water embayment of a major estuarine system in southeastern Louisiana. It has surface area of approximately 630 square miles (1.60 x 10 m ). Depths in offshore areas (greater than one mile from shore) range typically from 12-18 feet (4 to 6 m) with the bottom exhibiting a gradual relief. Localized depressions proximate to three tidal passes, which connect the lake to the Gulf of Mexico, slope to depths up to 40 feet (12m). The passes themselves have depths approaching 100 feet (30m). 

Heavy Metals The concentrations of Barium, Lead and Cadmium, with distance from the shoreline, are shown in Figure 9, Lead concentrations generally decreased with distance from the shoreline but there was considerable variability in this trend. Lead is transported as particulate matter in the marine environment (10, 11). Consequently, lower but highly variable concentrations offshore are to be expected. Other heavy metals studied did not exhibit any detectable trend with distance from the shoreline. Even the highly Insoluble heavy metal. Ba, did not show significantly lower concentrations in offshore areas. 

Distribution of salinity over the sea and its seasonal variations were dependent, largely, on the river water inflow and evaporation. Lower salinity was found in the Amudarya and Syrdarya mouth offshore areas. The greater part of fresh waters came in with the Amudarya flow into the southern part of the sea and was spread via the anticyclonic circulation along the western coast. High salinity was observed in shallow areas near the eastern coast with their impeded water exchange with the sea. The salinity field in the open sea was rather monotonous. 

After the winter bloom, water column stratification occurs in March-April, which results in the formation of the DCM that is characteristic of the system for the remainder of the year. The stratification starts in the offshore area in the Southeast Levantine Basin and spreads from there to the north and west. In summer the DCM is typically greater than 100 m deep with the waters above it depleted in inorganic N and P but containing significant amounts of dissolved organic nitrogen and phosphorus. 

The company was rescued, thanks to high investments outside of the Middle East. Since the early 1980s, British Petroleum has developed many more oil and gas fields in the North Sea. Among these have been, in the UK sector, Magnus, the Village gas fields at Miller and Bruce and, in Norwegian waters, Ula and Gyda. In Alaska, the construction of the Trans-Alaska Pipeline System enabled the Prudhoe Bay field to come on stream in 1977. In 1981, the Kuparuk field also started production, and towards the end of 1987, the world s first continuous commercial production was recorded from an offshore area in the Arctic when the Endicott field was commissioned. 

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