UNLOADING WELL LIQUIDS WITH THE AID OF FOAMING SURFACTANTS

Abstract

The use of foaming surfactants to mitigate the liquid loading phenomenon in oil & gas wells is a well-established practice in the industry. Literature review highlights the application of gas-liquid foamers in both onshore and offshore wells. Notably, Petrobras has employed foaming surfactants to some of its production fields. Tailored gas foamer sticks have been utilized regularly to enhance production in two Petrobras offshore gas fields located in the coastal waters of Rio Grande do Norte, Northern Brazil. To the best of authors’ knowledge, this represents the first instance of gas foamer technology (foamer sticks) being used in Petrobras's offshore fields, establishing a pioneering milestone. Furthermore, in Reconcavo basin, Bahia, Northern Brazil, ten aging wells from three Petrobras onshore light crude fields are currently utilizing the foamer stick technology to mitigate liquid loading effectively and sustain production. To fully undertand current trends in the field, the authors also investigated the recent advancements in a technique known as foam-assisted gas lift (FAGL), which involves dosing foamer surfactants into the gas lift stream of crude oil producers that have been killed by liquid loading. This technique can reduce the critical gas velocity (Turner et al., 1969) required to transport oil droplets within the multiphase gas flow, thereby enabling the resume of crude oil production using lower gas lift rates. Mastering the chemistry of foaming surfactants and its applications is essential for enhancing the performance of oil and gas reservoirs in the late stages of their production lifecycle. This manuscript focuses on foaming surfactant chemistry and presents compelling evidence supporting their application to well deliquification issues. Additionally, the manuscript concludes with an detailed discussion of in-house case studies showcasing the application of foamers in onshore and offshore producing scenarios.