Abstract

Complex and Extended Reach Drilling (ERD) well profiles are continuously pushing the limits of the drill string. Drill pipe with high-torque connections and increased tensile strength-to-weight ratios are required to overcome frictional drag forces, achieve improved hydraulic performance, control well trajectory and provide higher rates of penetration with optimal hole cleaning. While hole cleaning is generally considered to be well understood when drilling deviated and horizontal wells, many drillers still have difficulty properly managing the entire process.

Experience reveals that less-than optimal hole cleaning can lead to nonproductive time, poor bore-hole quality, and loss of the drill string or even the well. Large boreholes drilled at high ROPs will usually require additional rig time for essential cleanup. An in-depth analysis supported by key performance indicators (KPI) shows that using Mechanical Hole Cleaning Devices (MCD) in certain directional wells can achieve drilling efficiency gains with cost savings.

This paper addresses a new drill pipe design integrating hydro-mechanical features in the tool joint to address annular pressure issues prevalent in ERD wells. This innovative approach to drill pipe design aims at drilling with safer ECD (Equivalent Circulating Density) margins, reducing time spent on hole cleaning, improving hole quality and reducing Nonproductive Time (NPT). Short of a case history, performance improvements similar to efficiency gains achieved with the Hydroclean™ tool in highly deviated well can be expected.

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