Summary This paper presents a new composite drillpipe design that allows for an increase in the drilling reach of high-angle, directional wells. Horizontal reach is greatly limited by resisting friction forces that are created by the interaction between the drillstring and the lower side of the borehole. As the drillstring is advanced further into a highly directional borehole, the resisting friction forces give rise to ever-increasing applied-torque and axial (push)-force requirements. The gravitational forces (i.e., drillstring weight) dominate the buoyancy forces in nearly all modern drillstring designs that are currently used in highly directional drilling operations. These dominating gravitational forces create reaction forces between the drillpipe and the borehole wall. The reaction forces, when multiplied by the coefficient of friction between the drillstring and the borehole, yield tangential surface forces on the drillstring (normal to, and parallel with, the pipe axis). These forces resist the applied torque that rotates the drillstring and the applied axial (push) force that advances the drillstring. The new composite drillpipe design discussed in this paper reduces the specific weight of the drillpipe so that it will have nearly neutral buoyancy in 15.4-lbm/gal drilling muds. With this reduction in drillpipe specific weight, a drillstring with this new design will have greatly reduced gravitational forces and, in turn, greatly reduced resisting friction forces. This design feature allows the applied torque and axial force to be more effective, thus allowing greater extended-reach capabilities. It is estimated that the current extended horizontal-reach approximate limit of 10 km could be increased to 15 km or more with the application of this new composite drillpipe design. Such an increase in reach would have an important impact on the development of oil and gas fields that are economically dependent on advanced directional drilling technologies. This new composite drillpipe technology has been extensively bench and field tested and has been successfully used in short-radius drilling operations. The design features of the proposed light-weight composite drillpipe are discussed and compared to current horizontal drilling operational requirements (using a steel drillpipe). The new light-weight designs can be used with either steel or titanium tool joints (with a filament-wound composite-tube body structure between the tool joints). The drillpipe may be fabricated in either 30- or 42-ft lengths. Engineering feasibility studies have shown that this new light-weight composite drillpipe will be economical to fabricate and should provide significant economic advantages in the development of oil and gas fields requiring extensive directional drilling operations.