From Surface Production Operations: Design of Oil Handling Systems and Facilities, Volume One, Third Edition


This chapter discusses the concepts, theory, and sizing equations for the separation of two immiscible liquid phases (in this case, those liquids are normally crude oil and produced water). The separator design concepts presented in Chapter 4 relate to the two-phase separation of liquid and gas and are applicable to the separation of gas that takes place in three-phase separators, gas scrubbers, and any other device in which gas is separated from a liquid phase.

When oil and water are mixed with some intensity and then allowed to settle, a layer of relatively clean free water will appear at the bottom. The growth of this water layer with time will follow a curve as shown in Figure 5-1. After a period of time, ranging anywhere from 3 minutes to 30 minutes, the change in the water height will be negligible. The water fraction, obtained from gravity settling, is called "free water." It is normally beneficial to separate the free water before attempting to treat the remaining oil and emulsion layers.

Figure 5-1: Growth of water layer with time.

"Three-phase separator" and "free-water knockout" are terms used to describe pressure vessels that are designed to separate and remove the free water from a mixture of crude oil and water. Because flow normally enters these vessels directly from either (1) a producing well or (2) a separator operating at a higher pressure, the vessel must be designed to separate the gas that flashes from the liquid as well as separate the...

Products & Services
Oil and Water Separators
Oil and water separators (oil-water separators, oil water separators) are remediation devices that separate oil from water and/or wastewater. This product area includes both aboveground and underground systems for the containment and treatment of oil-contaminated water.
Desalination Equipment
Desalination equipment is used to remove salts and other minerals from water or soils, typically for drinking water, oilfield, and process separation applications.
Solid Phase Extraction Cartridges and Disks
Solid phase extraction (SPE) cartridges and disks are used to clean up a sample before using a chromatographic or other analytical method to quantify the amount of analyte(s) in the sample.
Evaporators are systems consisting of a heat exchanger or bath, valves, manifolds and temperature controls for conversion of a product (e.g., liquefied gas) from a liquid to a gaseous state.
Air Scrubbers, Wet Scrubbers, and Gas Scrubbers
Air scrubbers, wet scrubbers, and gas scrubbers are air pollution control devices that use a high-energy liquid spray to remove aerosol and gaseous pollutants from an air stream. The gases are removed either by absorption or chemical reaction.

Topics of Interest

Introduction Chapters 4 and 5 discuss the concepts for determining the diameter and length of two-phase and three-phase vertical and horizontal separators. This chapter addresses the selection of...

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