During drilling in complex formations, the sliding bearings of roller cone bits are continuously subjected to low-speed, heavy-load, and boundary lubrication conditions, under which adhesive failure readily occurs, severely limiting drilling efficiency. To enhance their wear resistance, a bionic texture inspired by shark denticles was designed and compared with conventional rectangular and circular textures. An equivalent pin–disk contact model was established based on Hertzian contact theory, and tribological experiments were conducted under typical formation conditions using a friction and wear testing machine. The friction coefficient, friction torque, and wear volume of different textures were measured under both lubricated and dry contact conditions, and the underlying mechanisms were elucidated through three-dimensional surface morphology analysis. The results show that the shark denticle-inspired texture reduced the friction coefficient and wear volume by 33.3% and 35%, respectively, under lubrication, while suppressing debris intrusion at the frictional interface under dry contact, thereby providing a degree of surface protection. This study offers theoretical guidance and experimental evidence for advancing the engineering application of bionic tribology in the petroleum industry.

Stable drainage of coalbed methane wells is essential for reducing reservoir pressure and promoting methane desorption. However, coal fines carried by produced water tend to accumulate and deposit within the standing valves of drainage pumps. To address this common problem, this study investigates the transport characteristics of coal fines within the standing valve during the liquid-dominated water-pumping stage of the plunger upstroke, with the standing valve fully open. Theoretical calculations, numerical simulations, and settling experiments were conducted for three coal fines size fractions of 60–100, 100–200, and 200–400 mesh to validate the model’s predictive capability for coal fines motion. The results show that the RNG k–ε model has the lowest mean absolute relative error, at 14.50%. A solid–liquid two-phase flow model was employed to comparatively analyze five valve seat cone angles ranging from 105° to 165° and representative inlet velocities of 0.1–0.4 m/s. The results indicate that the mixture within the standing valve accelerates markedly while passing through the narrow clearance between the valve ball and the valve seat and then decelerates in the region above the valve ball. The region above the valve ball and the valve seat transition region are the primary locations of instantaneous coal fines enrichment. Increasing the inlet velocity generally enhances coal fines transport capacity and reduces the local maximum solid-phase volume fraction. Larger coal fines particles exhibit more pronounced inertial deviation and a higher degree of local enrichment, whereas smaller particles show stronger flow-following behavior and a more dispersed spatial distribution. The results further indicate that, within the investigated structural range, the 150° valve seat cone angle provides the best overall balance between coal fines transport capacity and hydraulic resistance. Ultimately, the findings provide a theoretical foundation and methodological reference for understanding the anti-clogging mechanisms of CBM pump standing valves, optimizing structural parameters, and guiding the blockage-resistant design of downhole flow components.