Water-in-oil microemulsions for oilfield applications

摘要

A well treatment microemulsion includes an oil external phase, an internal aqueous phase and a hydrophilic surfactant. The surfactant has a hydrophile lipophile balance of between 8-18. The oil external phase may include d-Limonene, xylenes, light mineral oil, or kerosene. The surfactant is configured to emulsify the water of the internal aqueous phase into the oil of the external (continuous) phase. The surfactant may include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tristearate, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monolaurate or mixtures therebetween. The use of hydrophilic surfactants to emulsify an internal aqueous phase within an oil external microemulsion produces unexpected and beneficial results.