Testing Protocols For Optimized Drilling Fluid Design

With increasing wellbore complexity, drilling into more technically demanding areas, and increasing pressure to improve drilling economics, the drivers to improve and optimize drilling fluid performance have never been greater. The development of greater performing drilling fluids, in particular water based fluids, has been traditionally carried out via a few "standard" test protocols which give a very broad overview as to the potential performance of the fluid. With the development of significantly more advanced and specific drilling fluids over the last few years, a number of newer testing and evaluation protocols have also been developed. Utilizing the results from these newer testing protocols to evaluate the true potential for the performance of a drilling fluid can be misleading and can easily lead to a misapplication of the developed drilling fluid, resulting in at best a poor drilling fluid performance, and at worst a highly expensive mistake. This paper will review the various testing and evaluation protocols currently utilized for drilling fluid development, pointing out both the advantages and shortcomings of each of these protocols, both from a drilling performance standpoint and from an applicability standpoint. The paper will also indicate which combination of testing protocols will be more relevant for a given drilling scenario. The Authors will also discuss the development and field usage of a high performance water based drilling fluid showing how the application of the appropriate testing and evaluation protocols has both defined the correct application for these fluids, and has shown areas that require further developmen