An overview of chemical enhanced oil recovery and its status in India

India is currently producing crude oil from matured fields because of insufficient discoveries of new fields. Therefore, in order to control the energy crisis in India, enhanced oil recovery (EOR) techniques are required to reduce the import of crude from the OPEC (Organization of the Petroleum Exporting Countries). This review mentions chemical EOR techniques (polymers, surfactants, alkali, nanoparticles, and combined alkali-surfactant-polymer flooding) and operations in India. Chemical EOR methods are one of the most efficient methods for oil displacement. The efficiency is enhanced by interfacial tension (IFT) reduction using surfactants and alkali, and mobility control of injected water is done by adding a polymer to increase the volumetric sweep efficiency. This paper also reviews the current trend of chemical EOR, prospects of chemical EOR in Indian oilfields, the development of chemical EOR in India with their challenges raising with economics, and screening criteria for chemical EOR implementation on the field scale. Furthermore, the review gives a brief idea about chemical EOR implementation in Indian oilfields in future prospects to increase the additional oil recovery from existing depleted fields to reduce the import of crude oil. The outcome of this review depicts all chemical EOR operations and recovery rates both at the laboratory scale and field scale around the country. The additional recovery rates are compared from various chemical EOR methods like conventional chemical flooding methods and conventional chemicals combined with nanoparticles on a laboratory scale. The development of chemical EOR in the past few decades and the EOR policy given by the government of India has been mentioned in this review. The analysis provides an idea about enhanced recovery screening and implementation of chemical EOR methods in existing fields will significantly reduce the energy crisis in India. (c) 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).