Abstract

Foams are encountered in aqueous and nonaqueous systems throughout the upstream oil and gas industry from drilling and cementing to primary separation and production. Anti-foamers and defoamers are key ingredients to ensure efficient operations where uncontrolled foam causes problems. Application and performance of anti-foaming or defoaming agents are often assessed by blender tests or using sparge tubes. These tests, although simple and easily executable, are largely nonrepresentative of real-world conditions.

A versatile method, the FEAT (Foam and Air Entrainemnet Test), has been developed to better simulate the field behavior of oilfield antifoamers/defoamers in a laboratory setting. The FEAT is used to evaluate and optimize a variety of oilfield aqueous/nonaqueous systems which produce or encounter foaming conditions. Foam is generated by gas entrainment in the test media at a given temperature and pressure in the presence or absence of a foaming additive. The foamed media is then continuously recirculated while density and mass flow rates are measured and recorded to objectively quantify antifoamer/defoamer performance. The recirculating media may be altered, if desired, by successive dosage of salts, hydrocarbons or water over the time to better simulate field conditions and present a spectrum of medium behavior and additive performance. The dynamic nature of this measurement loop enables the evaluation of chemical additive systems under a variety of conditions such as brine buildup, water hardness, or hydrocarbon leaching. FEAT offers a versatile technique for developing new liquid and solid green products. Experimental results and field trials confirm the FEAT method better approximates field performance than commonly used tests. This allows for greater refinement of oilfield antifoamers and defoamers which offers both environmental and economical benefits.

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