ABSTRACT
Natural gas reservoirs always have water associated with them; gas in the reservoir is saturated by water. When the gas is produced water is produced too from the reservoir directly. Other water produced with the gas is water of condensation formed because of the changes in pressure and temperature during production. In the transmission of natural gas further condensation of water is troublesome (Lukacs, 1962, 1963). It can enlarge pressure drop in the line and frequently goes to corrosion problems. Therefore, water should be removed from the natural gas before it is offered to transmit in the pipeline. For these argue, the water content of sour gas could be important for engineering attention. In a study of the water content of natural gases Lukacs (1962, 1963) measured the water content of pure methane at 160°F and pressures up to 1,500 psia also Gillespie et al. (1980, 1984) predicted the water content of methane in the range of 122-167°F and for pressures from 200 to 2,000 psia. Sharma (1969) proposed a method for calculating the water content of sour gases, originally designed for hand calculations but it was slightly complicated. Bukacek (1990) suggested a relatively simple correlation for the water content of sweet gas, based on using an ideal contribution and a deviation factor. McKetta et al. published a chart for estimating the water content of sweet natural gas. This chart has been modified slightly over the years and has been reproduced in many publications (GPSA Engineering Data Book, 1998). Recently, Ning et al. (2000) proposed a correlation based on the McKetta et al. chart. This correlation reveals how difficult it can be to correlate something that is as seem-
ingly simple as the water content of natural gas. Maddox (1988) developed a method for estimating the water content of sour natural gas. His method assumes that the water content of sour gas is the sum of three terms sweet gas contribution (Methane, CO2 and H2S).
