Deep Water Condition

The equation describing the propagation of these waves can be written in the form of equation (5.1) after dropping the viscous term (which is most often negligible in a case involving deep waters)  

We take as the origin of altitudes 2 the free surface at rest (2 = 0). The liquid occupies the region z 0. During motion, there will be a small height deviation C- The vertical velocity at the surface is Vz z=o = dC/dt. In equation (5.45), we resolve the pressure into three separate terms  

It follows that p is proportional to exp qz). To avoid any divergence at large depths, we must choose 

Immediately underneath the surface, the local pressure must equal the Laplace pressure  

Since we have Vz z=q = we end up with the following dispersion relation  

---

The physical approach is not undisputable, as it does not take into account the conditions of the occurrences or of the production of the crude oil (e.g., onshore or offshore, water depths, climatic conditions, etc.). Therefore, some authors give a narrower definition of conventional oil. Campbell (2006), for instance, considers crude oil that is found under deep-water conditions (water depths greater 500 m) or in arctic regions, as well as NGL as unconventional oil. As a consequence, the remaining potential of conventional oil is estimated to be lower. 

Stein R. (1986) Organic carbon and sedimentation rate, further evidence for anoxic deep-water conditions in the Cenoma-nian/Turonian Atlantic Ocean. Mar. Geol. 72, 199-209. 

Condensed sections occur within a TST and the lowermost section of a HST if the sediment supply is low (Curiale et al., 1992 Wignall and Maynard, 1993). The deposits of a condensed section are generally fine-grained rocks that usually have a high concentration of organic matter and are formed in sediment starved, deep-water conditions (Wignall and Maynard, 1993). 

Matthaus, W., 1995. Natural variability and human impacts reflected in long-term changes in the Baltic deep water conditions—a brief review. Deutsche Hydrographische Zeitschrift, 47, 47-65. 

Matthaus, W., Schinke, H., 1999. The influence of river runoff on deep water conditions of the Baltic Sea. Hydrobiologica, 393, 1-10. 

They suggested that most of the carbonate dissolution in the deep ocean (Fig. 9.5) occurs within the sediments (85 %). The extension of their results from Pacific and Indian Ocean to the Atlantic Ocean leading to 120 10 molyr of global dissolved carbon fluxes from sediments may, however, be critical because of the completely different deep-water conditions in the Indo-Pacific and the Atlantic. Deep ocean waters in the Indian and Pacific Oceans are known to be much older and depleted in CO implying that a much higher proportion of calcite dissolution contributes to the total alkalinity input there. However, despite this problem of different bottom-... 

A sinusoidal wave solution of Laplace s equation satisfying both the free surface condition and the deep water condition is... 

The presented crabbing manoeuvre can be examined for the different combinations of main engines (Dead Slow, Slow) and bow thrusters (50% or 100% of maximum available power) settings at shallow water (water depth to ship draft ratio h/T =1.2) and deep water conditions (h/T = 3) and at different distances from the berth. In Figure 1 the assumed distance to the berth is equal to 0.75 ship beam. 

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... 

Acid-base equilibria Partly Near-surface studies tend to investigate fresh or moderately saline water, which creates quite different conditions for acid-base equilibria. Studies of ocean geochemistry come closest to approximating deep-well conditions. 

Hexachloroethane released to water or soil may volatilize into air or adsorb onto soil and sediments. Volatilization appears to be the major removal mechanism for hexachloroethane in surface waters (Howard 1989). The volatilization rate from aquatic systems depends on specific conditions, including adsorption to sediments, temperature, agitation, and air flow rate. Volatilization is expected to be rapid from turbulent shallow water, with a half-life of about 70 hours in a 2 m deep water body (Spanggord et al. 1985). A volatilization half-life of 15 hours for hexachloroethane in a model river 1 m deep, flowing 1 m/sec with a wind speed of 3 m/sec was calculated (Howard 1989). Measured half-lives of 40.7 and 45 minutes for hexachloroethane volatilization from dilute solutions at 25 C in a beaker 6.5 cm deep, stirred at 200 rpm, were reported (Dilling 1977 Dilling et al. 1975). Removal of 90% of the hexachloroethane required more than 120 minutes (Dilling et al. 1975). The relationship of these laboratory data to volatilization rates from natural waters is not clear (Callahan et al. 1979). 

Because phosphate is released during remineralization with no decrease in O2, the A02/AP0 produced via denitrification should be lower than that predicted by the aerobic respiration of Redfield-Richards planktonic detritus. To reach the suboxic conditions required for denitrification requires the aerobic respiration of a considerable amount of POM and, hence, release of phosphate. Thus, A02/AP0 ratios less than 138 are most likely to be found in waters with high phosphate concentrations. The prevalence of denitrification in deep waters is suggested by their low (14.7) average N-to-P ratio (Figure 8.3). Areas where the OMZ are pronoimced, such as coastal upwelling areas, have particularly low N-to-P ratios as shown in Figure 10.7. 

Formation of the shallow-water concretions is associated with anoxic conditions that range in duration from seasonal to nearly continuous. For example, in the Baltic Sea, nodules and crusts are mostly found around the margins of the deep anoxic basins. They form from Mn and Fe that accumulates from the reduction of Mn and Fe oxides in the anoxic deep waters. When the basin is periodically flushed with oxic water from the North Sea, about once a decade, the concretions undergo growth as the fresh supply of metals is oxidized. 

The model provided in Figure 20.1 is for an ocean basin whose abyssal plains all lie below the CCD. This most closely resembles the conditions in the North Pacific, whereas the rest of the ocean basins have a significant portion of their abyssal plains lying above the CCD, and, hence, contain some calcareous oozes. From a global perspective, calcareous oozes are more abundant than siliceous oozes. This is caused by two phenomena (1) all seawater is undersaturated with respect to opal, whereas all surface waters and 20% of the deep waters are saturated with respect to calcite, and (2) siliceous plankton are dominant only in upwelling areas. 

---