Polymer dispersed system for in-situ fluid diversion

High initial heterogeneity coefficient of reservoir coupled by a long period of exploitation, leads to a decrease in the effectiveness of most  EOR methods based on the displacing agents injection and  significantly increase economic costs. So, for example, in fields where the main oil recovery mechanism is waterflooding appearance of high-permeability channels is inevitable. Therefore this phenomenon negatively affects oil recovery factor, the displacement front uniformity and the injectivity profile. One of the most successful technologies to overcome these complications is the in-situ fluid diversion techniques based on creation of gel banks deep in the formation. The article presents a polymer-dispersed system (PDS) for deep flow diversion using on modified bentonite particles. Initially, bentonite particles were intercalated with precursor molecules, then copolymers of N-isopropylacrylamide (NIPAM) and acrylic acid (AA) were grafted onto the hydrophilic surface of bentonite particles by a graft polymerization reaction. The paper presents the study results of the physicochemical properties, rheology and colloid stability. The residual resistance factor has also been studied on sandpacks and core samples from the Azeri-Chirag-Guneshli field. The results of experiments shows increased hydraulic resistance while injection of PDS due to a sharp decrease in permeability. Core studies confirmed obtained results, showing a 61% decrease in permeability accompanied by an 11% increase in oil recovery. It was concluded that proposed composition is effective as deedp divertion agent and can increase oil recovery.