Mismanaging mud characteristics can create drilling issues and financial losses. Field drilling operations can avoid lost circulation (mud loss), stuck drill strings, uncontrolled blowouts, and caving shale by carefully selecting drilling mud that matches the formation characteristics of a well. The aim of this study is to develop a mud formulation that effectively mitigates shale-related issues while preserving the integrity of the physical properties of the formation. The use of appropriate polymer mud and shale stabilizers at 250 degrees Celcius, with KCl at 9 percent and Soltex at 2, 4, and 6 ppb, will help this study achieve its aim. In this study, clay swelling is measured with a linear swell meter. Test results will be shown as charts or graphs. We can see from the linear swell meter graph that using KCl polymer mud with Soltex at a concentration of 4 ppb is an effective way to reduce shale formation swelling by about 21.20 percent. This study proposes employing KCl polymer and Soltex to decrease shale swelling at high temperatures, which could have a positive effect on petroleum engineering. Precision in drilling mud composition and selection can improve drilling operations, which could reduce drilling expenses and financial losses.