Breaking of Oil -Water Emulsion for the Improvement of Oil Recovery Operations in the Niger Delta Oilfields

Emulsified water is generally present in crude oil as a result of mixing occurring during production operations. The formation of emulsion leads to problems in production and also transportation. Therefore the need to break oil/water emulsions system through demulsification process using chemical surfactants for improved oil recovery operations. Selected cationic surfactants were effective in separating oil-water emulsions expected during a surfactant/polymer (SP) process for improved oil recovery. The aqueous phase of the emulsion contained an anionic surfactant blend, alcohol and partially hydrolyzed polyacrylamide. Brine composition was a suitable mixture of formation brine with brine from polymer drive. The crude oil had an API gravity of 47.2. Bottle tests were conducted at ambient temperature, which is near the reservoir temperature. Both oil and water phases of acceptable quality were obtained after settling upon addition of 200ppm of octytrimethylammonium bromide (C8TAM) at ambient temperature. Microscopy image showed significant coalescence after only 1 minute in C8TAM system as the cationic surfactant reduced electrostatic repulsion among drops and shifted system behavior towards the balanced state between hydrophilic and lipohilic effect well-known to reduce emulsion stability. The amount of cationic surfactant may be reduced by reduced by adding it simultaneously with anionic demulsifier resin.