Table 9-2 lists the various methods employed in produced water treating systems and the types of equipment that employ each method. Figure 9-4 shows a typical produced water treating system configuration. Produced water will always have some form of primary treating prior to disposal. This system could take the form of a skim tank, skim vessel, CPI, cross-flow separator, or gas flotation unit. Other than the gas flotation unit, all of these devices employ gravity separation techniques. Depending upon the severity of the treating problem, secondary treatment may be required. Secondary treatment could utilize a CPI, a cross-flow separator, or a gas flotation unit. Liquid-liquid hydrocyclones or centrifuges are often used either in a single stage or with an upstream or downstream skim vessel or flotation unit.

Figure 9-4: Typical produced water treating system.

Offshore, produced water can be piped directly overboard after treating, or it can be routed through a disposal pile or a skim pile. Water from the deck drains must be treated for...