石油文章翻译、求解、谢谢

Under high water cut conditions, oil is produced as an oil-in-water dispersion. During production the oil droplets will decrease insize: at the well bottom they are much larger than at the surface, whichhas implications for the separation of the produced fluids. This paperdescribes laboratory work on the break-up processes occurring in thetubing and in the choke valve.Experiments carried out with two model tubings yielded that themaximum droplet size decreases with the volume flow rate andincreases with the viscosity of the dispersed phase, oil. The measuredmaximum droplet size varied between about 100 and 500 뗰m. In themodel choke valves, much smaller values for the maximum dropletsize were found, down to about 20 뗰m. Also for the choke valve anincreasing volume flow led to a decreasing maximum droplet size. Inthis case, however, the effect of the dispersed phase viscosity wassmall. The experimental data are in reasonable agreement withtheories on the mechanism of droplet break-up.An important conclusion is, that during oil production under highwater cut conditions, break-up of oil droplets will predominantly takeplace in the choke valve.As an oil reservoir matures, the water cut of the producing wellsgenerally increases. For reservoirs in the North Sea, water cuts ofapproximately 90 % and higher are not uncommon. An increasedwater cut will lead to increased efforts to handle the production fluidsand, evidently, to increased water amounts. For a production rate of,say, 30,000 barrels per day (5.5∠10-2 m3/s) and a water cut of 90 %,4.3∠103 m3 of water has to be disposed daily. The quality of thedisposed water has to meet stringent environmental requirements: themonthly average of the oil contents of the disposed water must notexceed 40 ppm. This low concentration together with the largeamounts of water make high demands upon the separation facilities.In order to obtain a high separation efficiency, many parametershave to be optimized (Davies et al.,1996). In general, at high watercuts and high production rates, the oil water mixture will form an oil-in-water dispersion. The stability of this dispersion depends amongother factors on the oil-droplet-size distribution of the mixture. Fordroplet sizes of 60 뗰m, separation cannot be achieved in settling tanksanymore, while the efficiency of plate separators decreases rapidly fordroplets smaller than 30 뗰m.