Drilling Starch in drilling fluid usages provide improved high temperature fluid loss performance when incorporated into well drilling fluids. They may also be used in other applications for which cellulosic polymers have heretofore been employed because of their better high temperature tolerance compared to conventional Starch polymers.
Drilling starch in drilling fluid in drilling wells, a mud-like fluid is pumped into the hole to clean and cool the drill bit and to flush to the Surface the rock cuttings that are torn loose by the drill bit. The drilling starch drilling fluid must have certain physical characteristics. The most important of these is the viscosity and the water holding or retaining characteristics of the fluid. The use of starch in well drilling fluid is well known. It is also well known that conventional Starches tend to break down at elevated temperatures for extended periods of time. Specifically, conventional Starch tends to break down or burn up at temperatures of 225 F. or higher when Subject to that temperature for longer than four hours. High temperatures for extended periods of time are often encountered in deeper Wells during the drilling process. The breakdown of conventional Starch results in an increase in the consumption of the conventional Starch needed in the mud.