Abstract:

Oil and gas industry is currently facing immense challenge for enhancing the production to meet the increasing demand of oil worldwide. The production from matured reservoirs is declining sharply and the discovery of the new oil and gas fields is not noteworthy. Thus, to meet the increasing demand, the oil and gas industry is looking for methods to recover more oil from the matured fields, as it is estimated that approximately two third of the original oil in place (OOIP) in the mature reservoirs is very difficult to extract by primary and secondary recovery methods. For this reason, tertiary oil recovery methods such as chemical, thermal, miscible and microbial are developed to lower the residual oil saturation by enhancing the oil recovery. Chemical enhanced oil recovery (CEOR) is amongst the popular techniques of EOR that employs the injection of surfactant, polymer, surfactant-polymer, alkali-surfactant-polymer, and micro-emulsion slug in the reservoir to produce the trapped oil. Nanotechnology has been developed in recent years and nanoparticles have become more important in the field of enhanced oil recovery. Nanofluids (dispersed nanoparticles in water) can alter the wettability of reservoir rock, oil/water interfacial tension, and structural disjoining pressure. Synergistics effects of nanoparticles with surfactant and polymer also improve the thermal stability of the chemical slugs and quite beneficial for application of enhanced oil recovery at harsh conditions. Nanocomposites have also good wear resistance, a high thermal stability, and have an excellent chemical stability and hence suitable for same application. Nanoemulsion possesses unique properties such as kinetic stability, low IFT, improved wetting behaviour and exceptional rheological performance that significantly influence the oil recovery factors. Additionally, Nanoemulsion injection reduces surfactant adsorption over the rock surfaces, which improves the chemical carrying ability of aqueous phase and blockage of high permeable zones. Now a days, low saline and smart water flooding are getting attention for enhanced oil recovery due to its easiness to use implications, less cost & environment-friendly nature. The presentation will cover the fundamental mechanisms of different types of chemical enhanced oil recoveries along with their recent advances and opportunities.