**5. Role of biopolymers in HPWBMs**

Various additives are used in the mud with different dosages to enhance the viscosity of drilling mud. During drilling the pay zone section, the main concern is to reduce the invasion of filtrate and solids into the exposed formation. This invasion can cause irreversible problems that cause multiple folds decline in production. Thus, nondamaging mud containing biopolymer and other acid-soluble materials are added to the mud for drilling of such zones. Various biopolymers, including gums (xanthan, guar, and diutan), lignins, starches (both native and modified), cellulose, etc., are widely used in oil well drilling. These gums have been further modified to increase their thermal stability and salt resistance functionality. **Figure 1** shows xanthan, diutan, and guar gum structure.

#### *Utilization of Biopolymers in Water Based Drilling Muds DOI: http://dx.doi.org/10.5772/intechopen.105516*

Due to the environmental concerns about the usage of huge quantities of chemicals and their disposal issues, the oil industry is looking for bio-based/biodegradable materials with very little or no impact on the environment. Therefore, various waste products and other biomaterials have been investigated to substitute the hazardous chemicals used in recent years. These materials include but are not limited to agarwood waste, rice husk, psyllium husk, and groundnut husk: dates, grass, wood, pistachio shell, mandarin peels, palm tree leaves, green olive pits, Cupressus cones powder, etc. The mentioned materials showed that the mud containing these agents could significantly improve the mud properties. Moreover, the overdependence on such expensive commercial materials is reduced by utilizing such additives. These materials are easily available everywhere, and their proper utilization can reduce the extra cost and ensure environmental cleanliness.
