Friction Reduction Technology Tailored to Extreme Flow Rates

Abstract

Non-thru bore drilling tools often feature limited flow range capabilities due to their design complexity. An ever-growing demand in high flow rates required a new technical solution that has the lowest possible pressure drop across the tool. Potential erosion issues as well as consistent functionality of the tool were key design requirements. A new friction reduction technology is presented that addresses the applications with flow rates ranging from low to high. Initial computational fluid dynamics (CFD) analysis suggested the flow split can be executed by restriction at the tail end of the power section. This, however, was challenged by the first test run that took place at 550gpm (5¼-in. tool outside diameter [OD]). While the run objectives were met in its entirety, upon tear down, the early signs of erosion were noticed on the valve assembly. With this evidence on hand, a critical design change was implemented, and as a result, the restriction was moved down the power section to spare the vortex at its tail end. Further improvement was retrofitted to protect the restriction itself with a simple addition of a sleeve. Further field runs were executed with the new tool setup. As the run count progressed, the newly redesigned technology achieved the objectives by delivering effective friction reduction at consistent frequency and pressure drop. It soon became evident that the step change in flow rate did not affect the tool wear and tear. Since its inception the tool has set two field records. The first commercial run marked the fastest curve in the county. As this technology rises to prominence in the US and international markets, more operators are experiencing the savings and lower Authorization For Expenditure (AFEs). The novelty of the design presented in this paper is in the drilling engineer's ability to design and construct wells with increased complexity (high dog leg severity [DLS], directional difficulty index [DDI], extended reach, and multi-lateral) where friction reduction technologies are critical to achieving run objectives. This technology fills a technical gap by meeting the new standards of high torque and flow rates in a compact and robust design. At the time of this writing, no other friction reduction technology meets these tool specifications.