Amplitude modulation in surfactant and polymer-based water-in-oil emulsions: A novel approach to enhance separation rate and mitigate chaining effects

Abstract

Oil wells can eventually run out of oil if used for an extended period. Various polymers and surfactants are used to enhance oil recovery to extend the useful life of a well and improve the recovery process. These chemicals are added to make the extraction process easier. However, the emulsion that results from this process can be difficult to break down because of the added chemicals. Therefore, special measures are necessary to recover the crude oil effectively by breaking the emulsion. Electrocoalescers are specialized large-scale units designed for the purpose of separating water from emulsions. Improving the performance of an electrocoalescer involves achieving faster dehydration of the emulsion while ensuring safe operation. This means increasing the rate of water separation without compromising safety. The proposed technique aims to improve separation by modulation of the AC electric field. This modulation consists of a step with a high-amplitude electric field, followed by a step with a low-amplitude electric field, then repeated. This work involves a study of four types of emulsions that were used: (1) water-in-oil emulsion without surfactant/polymer, (2) polymer-stabilized water-in-oil emulsion, (3) surfactant stabilized water-in-oil emulsion, and (4) surfactant and polymer mixed-stabilized water-in-oil emulsion. The electrocoalescence process has faster kinetics compared to conventional methods. Modulation facilitates drop chaining during high voltage and effective coalescence during low voltage. It has been observed that an increase in the conductivity of the dispersed phase can lead to an increase in non-coalescence. The surfactant (SDS) and polymer (HPAM) mixture become more challenging to separate.