The use of Zinc Dialkyl Dithiophosphate as a Lubricant Enhancer for Drilling Fluids particularly Silicate-based Drilling Fluids

As well profiles become more challenging, drilling fluids and lubricants face the need to provide further reductions in torque and drag. Tightening environmental regulations have placed further pressure on operators who now look more frequently to water based fluids to solve these challenges despite their higher coefficients of friction. One of the most commonly used methods for reducing toque and drag is the addition of a lubricant to the drilling fluid. Lab results show that the addition of a minor amount of zinc dialkly dithiophosphate (ZDDP) is an effective means of improving the performance of most classes of lubricants including those used with water base fluids. Under downhole conditions the ZDDP decomposes to form a polyphosphate film on the surface of the drill string and casing. This film is proving to serve multiple roles, reducing wear and corrosion on the underlying metal surface while working synergistically with other lubricants used.