Biopolymers are gaining increased attention in the industry due to their unique characteristics, including being cost-effective, environmentally friendly, and biodegradable. It is also worth noting that natural polymers can be obtained in significant quantities from various renewable sources, whereas synthetic polymers are derived from non-renewable petroleum resources. Enhanced oil recovery (EOR) using biopolymers such as galactomannan, xanthan, welan gum, acacia gum, carboxy methyl cellulose, and corn starch is a developing trend and is projected to replace synthetic polymers (hydrophobically associated polyacrylamides) in the nearby future. The choice of polymers to be utilized in EOR technologies should be based on their cost and availability in addition to their functional properties. Biopolymers in enhanced oil recovery serve to enhance the mobility ratio by increasing the viscosity of displacing fluid and reducing permeability. Even though biopolymers have a tough structure and long polysaccharide chains that make them suitable for enduring severe reservoir conditions, they are highly susceptible to bacterial destruction. In this comprehensive review, we have illustrated the different techniques used to enhance the performance of biopolymers (xanthan gum, guar gum, and starch) in enhanced oil recovery and create new composites that can overcome the challenges faced by these biopolymers under reservoir conditions. We have found that the most famous and favorable techniques used in this approach are, grafting copolymerization, nanocomposites functionalization, amphiphilic style, and hydrogel formation. The review also discussed some other biopolymers (carboxy methyl cellulose, welan gum, and acacia gum) that can be utilized to improve oil recovery and evaluated how widely they have been applied in this field. In this review, we have addressed several important issues (knowledge gaps) that have not been covered in recent studies. We have also provided recommendations and prospects for the successful future implementation of these composites in the EOR field. In conclusion, we hope that this review will help in better understanding the use of these modified biopolymers for enhanced oil recovery (EOR).
