Filtration control properties of four native starches in water-based drilling fluids

As a key performance parameter of drilling fluids, filtration loss has received extensive attention. Although native starches have been proven to effectively control filtration, there are few comparative studies on native starches extracted from different plant sources. The objective of this study was to investigate the physicochemical properties of four native starches (wheat, corn, potato and cassava starches) and assess their effectiveness in filtration control within water-based drilling fluids, thereby elucidating the filtration control mechanisms of starch granules. Experimental results showed that after aging at temperatures ranging from 50 to 150 °C, potato starch exhibited good filtration control, achieving a minimum filtration loss of 4.0 mL. Amylopectin can directly affect the gelatinization temperature and internal structure of native starches, and gelatinized starch granules with a higher amylopectin content contain more active groups that interact with bentonite particles. These factors are the main reasons for the enhanced filtration control and temperature resistance of potato starch in water-based drilling fluids. The insights gained from this research on filtration control using native starches will promote the application and development of starches and their derivatives in water-based drilling fluids.