Experimental Analysis of Bubble-Breaker Devices

Multiphase flow in pipes plays an important role in the oil and gas industry because the pressure losses along tubings, flowlines, and risers have a direct impact on overall production. In offshore wells, this is more critical because of the greater depths and longer tie-backs, which increase both the frictional and gravitational pressure losses. In this context, multiphase-flow optimization, isolated or in association with artificial lift or boosting methods, may significantly help to increase production. This work investigates the potential of a method to optimize multiphase flow in vertical pipes through an imposed change in the gas-bubble geometry, more specifically in the bubble diameter. This change in the bubble's geometry is performed by a mechanical device and may reduce the slip between phases, and as a consequence, decrease the gravitational term in the pressure gradient, resulting in less overall pressure loss. In principle, it can be applied to oil-flowing wells with medium to high gas/oil content or to gas lifted wells. This paper explains the relationship between bubble diameter and pressure drop, and presents experimental results that support the potential of such technology. The experimental data were collected first in a small-scale installation using air and water, and then in an experimental well with natural gas and oil. Several geometries of the mechanical bubble-breaker device were tested and compared.