A study in lignin capability to improve strength and water absorbency of starch polymers: a potential heat-resistant fluid-loss-controller in water based drilling fluids

*Embargoed until January 2024In the oil and gas industries, drilling deep wells has rapidly become more significant to meet the global demand. The design of drilling fluids and choosing the proper additives are very important for the drilling operation's success. Rheological behaviour and filtration-loss properties are the main factors to control for effective drilling operations. So, the study of an effective fluid loss controller and a rheology modifier is necessary to designing drilling fluids formulations and determining their proper performance during operations. Starch, as a natural polymer, is broadly utilized in the drilling industry, thanks to its specific structure and solubility in water. The main duties of starch in drilling fluids formulations are reducing fluid loss and improving the viscosity of fluid during drilling operations. One of the main problems of using starch in water-based fluids (WBFs) is being inefficient in high pressure and high temperature (HPHT) condition and shear force. Numerous studies have been conducted to elevate the thermal stability of starch to strengthen it for harsh conditions. In some studies, starch was replaced by new polymers like Carboxymethyl Cellulose (CMC) and other synthetic polymers, to overcome these problems. These polymers are not effective enough and are relatively expensive, so one needs to consider using alternative materials or natural ingredients to make drilling more economical and more efficient, especially in deeper wells with higher temperatures. [...