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Figure 10 Two-step mechanism of separating gas from oil.

In separating the gas from oil, a mechanical mechanism could be
suggested [3], as shown in Figure 10, which implies the following two
steps:

(a) To separate oil from gas: Here, we are concerned primarily with
recovering as much oil as we can from the gas stream. Density
difference or gravity differential is responsible for this
separation. At the separator’s operating condition of high
pressure, this difference in density between oil and gas becomes
small (gas law). Oil is about eight times as dense as the gas. This
could be a sufficient driving force for the liquid particles to
separate and settle down. This is especially true for large-sized
particles, having diameter of 100 mm or more. For smaller ones,
mist extractors are needed.
(b) To remove gas from oil: The objective here is to recover and
collect any non solution gas that may be entrained or ‘‘locked’’
in the oil. Recommended methods to achieve this are settling,
agitation, and applying heat and chemicals.

3.5.2 Commercial Types of Gas–Oil Separator
Based on the configuration, the most common types of separator are
horizontal, vertical, and spherical, as illustrated in Figures 11, 12, and 13,
respectively. A concise comparison among these three types is presented in
Table 3. Large horizontal gas–oil separators are used almost exclusively in
processing well fluids in the Middle East, where the gas–oil ratio of the
producing fields is high. Multistage GOSPs normally consists of three or
more separators.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.