While hole cleaning is generally considered to be well understood in drilling deviated and horizontal wells, drillers still have difficulty properly managing the entire process. Experience reveals that less-than optimal hole cleaning can lead to non-productive time, poor bore-hole quality, and loss of drill string or even the well.

Efficient cuttings transport and keeping the well clean enough for trouble–free operations are challenges predominantly associated with drilling complex wells. Cuttings tend to accumulate on the low side of the hole forming thick beds causing the flow velocity to become insufficient to keep the hole clean. Large boreholes drilled at high ROPs will usually require additional rig time for cleanup. Time spent on hole cleaning operations can be significant, but essential. A more in-depth analysis of performance drilling in certain directional well profiles reveals a more efficient approach using Mechanical Hole Cleaning Devices (MCD) when economically justifiable.

This paper addresses a new drill pipe design integrating hydro-mechanical features in each tool joint has been developed to overcome limitations of MCDs in smaller diameter holes, and to extend the application of Hydroclean drill pipe to ERD (Extended Reach Drilling) wells. This innovation enables drilling with safer ECD (Equivalent Circulating Density) margins and reducing time spent on hole cleaning operations. Short of a full analysis with Key Performance Indicators, performance improvements compared with standard drill pipe are expected as a result of efficiency gains achieved by the three main principles of hole cleaning; scooping and eroding cutting beds at each tool joint, keeping cuttings continuously flowing on the high side of the hole, and maintaining the conveyor belts effect along the drill string while rotating.

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