Method to Evaluate Foaming in Petroleum

Abstract

In oilfields, gravitational separation tanks are generally used to separate the oil, gas and water phases, remove emulsifying agents present at the interfaces and permit the coalescence of water droplets associated with the crude oil being pumped. The main problem that influences the performance of these separators is the formation of foam. In this work, a method was developed to evaluate foaming in crude oil in laboratory scale, reproducing the operation conditions in gas-oil separators in real fields. This method was employed with seven crude oil samples, and the performance of silicone antifoams with different molar masses could be tested. The results indicated that the method of evaluating the breakdown of foam in oil by using the Aging Cell apparatus in a roller oven proved to be suitable. It was observed that the oil viscosity is a determining factor in predicting whether or not foam will form.

Development and evaluation of oil in water nanoemulsions based on polyether silicone as demulsifier and antifoam agents for petroleum

“…The (o/w) nanoemulsions as defoamers for petroleum efficiency evaluation was executed based on the methodology developed in lab and utilized in previous work …”

“…Methods that aim the reduction of amount of formed foam consist basically on the filtration of solid particles (responsible for the stabilization of foam in petroleum) and on the utilization of chemical agents known as defoamers . These are also added in solution, the solvents, and additives concentrations being similar to the ones used in the demulsification process.…”

Non-Aqueous and Crude Oil Foams

“…In fact, Poindexter et al [62] indicate that crude oils with bulk viscosities lower than 150 cP at 37.8°C produce little or no foam. On the other hand, Fraga et al [64] have evaluated high viscosity oils and find that these oils did not generate foams even when they contain high levels of stabilizing species.…”

“…Moreover the methods do not reproduce the conditions found in the petroleum industry and the type of foam generated is not representative of actual crude-oil foams. For these reasons, alternative methods have been developed to match field conditions, [59,64]. Petroleum foam formation during extraction or gas-separation operations is due to rapid depressurisation that causes massive bubble nucleation of dissolved gas, much like that observed when a bottle of champagne is shaken and then abruptly opened.…”

“…The volume of foamy oil and dispersed gas are estimated by monitoring the crude oil foam height as a function of time. In the test used by Fraga et al [64], gas saturation can be assisted by mechanical agitation and the overall temperature can be controlled to mimic that found in the field. A total of 150 mL of oil is transferred to a compression cell which is sealed and pressurized to the desired pressure.…”