Rotary steerable systems (RSS) have been in the market for more than a decade and their advantages in delivering smooth well bores and cost savings due to performance improvements have been well established.

Today's RSS are however limited in the maximum dogleg severity that they can deliver compared to the conventional positive displacement motors (PDM). For example in the 8.5in section the maximum dogleg quoted by major service companies are in the range of six to eight degree per hundred feet. Any well planned above this dog leg range in this hole section is drilled by PDM.

A new rotary steerable drilling tool capable of delivering reliable and consistent doglegs in the range of 0 -15 deg/100ft in any type of formation has been developed. Higher curvature rates imply that kick-off-points can be pushed deeper, which helps improve ROP due to longer vertical section drilled. Additionally at high curvature rates, horizontal displacement needed to land the well is dramatically reduced (380ft at 15deg DLS compared to 1145ft at 5deg DLS). This helps in early entry into reservoir and higher production rates.

In addition to these capabilities, the system can also kick-off from vertical,perform open-hole sidetracks, execute closed loop trajectory controls. All these capabilities enable the drilling of even more complex well profiles in one run without the need to trip out of hole, resulting in significant performance improvements, time and cost savings.

In this paper we will discuss the principle of operation of the high dogleg RSS and we will also present results from various filed tests validating the applications of the tool.