Advanced Approaches to Depth Optimization in Large-Diameter Water Well Drilling in Mangystau Peninsula
Abstract
Providing a reliable water supply to rural areas of the Mangystau Peninsula requires the construction of large-diameter wells, often in challenging geological conditions. However, the achievable drilling depth is limited by various factors related to hydraulics and the mechanical configuration of the drilling system. This study investigates how key geological and technological parameters influence the maximum depth of large-diameter wells when reverse-circulation drilling is used. A theoretical model was developed to simulate the hydraulic processes within the wellbore and drill string, incorporating variables such as drilling fluid flow rate, rising flow velocity, bit pressure loss, pipe dimensions, and vacuum generated by the pump. The model was used to assess the sensitivity of drilling depth to changes in fluid flow, pipe wall thickness, outside pipe diameter, drilling rate, and vacuum magnitude. The results show that an increase in fluid flow rate or drilling rate significantly reduces the achievable depth due to quadratic growth in hydraulic losses. Conversely, increasing the outer diameter of the drill pipes or the pump vacuum enhances the maximum depth. These findings can help optimize the design of drilling systems for large-diameter water wells and guide future research on cost-effective and deeper well construction in arid regions.