A Study on Clay-Based Fluid for Shallow Well Drilling

Drilling fluid is essential to the drilling operation to clean the hole, stabilize the wellbore, and reduce friction. Clay-based fluid is commonly used in drilling petroleum wells, bored piles, and water wells. Its characteristic includes rheology and filtration, which strongly affect the drilling process and afterward operation. This study aims to investigate the effect of clay addition on the rheological and filtration loss property of drilling fluid. The bentonite powder was added to tap water with various concentrations of 1 to 5% by weight and stirred using a high-speed stirrer in the laboratory. The rheology behavior of fluids was characterized by using an 8-speed rotational viscometer. The clay-based fluids were then analyzed for filtration loss properties following the American Petroleum Institute (API) test method. The addition of clay material resulted in improved apparent viscosity (AV), plastic viscosity (PV), yield point (YP), and gel strength (GS). In addition, the increased bentonite reduced the volume of fluid loss by maintaining a thicker filtration cake.