This proof of concept research evaluates the performance of a surfactant/b-cyclodextrin (b-CD) inclusion complex during chemical flooding for enhanced oil recovery. It was hypothesized that the encapsulated surfactant propagates well through the porous media. Sodium dodecyl sulfate (SDS) was used to study the surfactant/b-CD complexations. Phase behavior analysis was carried out to prepare the most favorable chemical slug formulation. A series of core flooding tests were conducted to determine the efficiency of the SDS/b-CD inclusion complex in displacing residual oil. Surfactant flooding was conducted as tertiary oil recovery mode (after mature water flooding) by injecting 0.3 pore volume (PV) of the optimum surfactant slug that was chased by 0.3 PV of a polymer slug; followed by continuous water flooding until oil production stopped. The experimental results indicate that the encapsulated surfactant propagates well through the sandpack system and consistently produces higher incremental oil recoveries that range from 40 to 82 % over the incremental oil recovery achieved by conventional surfactant flooding.
KeywordsSurfactant delivery system Á Surfactant carrier system Á Surfactant/b-cyclodextrin complexation Á Surfactant/b-cyclodextrin inclusion complexes Á Surfactant adsorption Á Surfactant adsorption inhibition Á Surfactant flooding Á Enhanced oil recovery Á Surfactant encapsulation in b-cyclodextrin List of symbols k Permeability in md (millidarcy) S or Residual oil saturation in fraction t Time uFlux in cm/h V sm Surfactant volume in the microemulsion phase V wm Water volume in the microemulsion phase V om Oil volume in the microemulsion phase r mw Interfacial tension (IFT) between the microemulsion/water phases r mo Interfacial tension (IFT) between the microemulsion/oil phases / Porosity