In North America, shale gas wells are typically drilled with build rates of 10°–14°/100ft to land, followed by 3000–5000 ft horizontal sections. As more shale plays open up, horizontal sections have been extended to seek more shale exposure. Today, the majority of shale gas wells are drilled using conventional steerable motors, but as horizontal sections get longer, Rotary Steerable Systems (RSS) become a more viable option to reach the target depth.

Standard RSS currently on the market cannot provide sufficient build rates to drill the curve on shale gas well designs. However, as wells step out further, it has become more common to drill the curve with steerable motors and to drill the lateral with RSS. On shale wells where the curve and the lateral are drilled in the same hole size, it would be more efficient to drill the entire well with RSS. Hence, there is a necessity for higher-dogleg RSS for these applications.

This paper describes the development and testing phase of a new 6 ¾-in. RSS that can produce higher build rates than the standard RSS on the market. During testing, the 6 ¾-in. RSS proved to be capable of producing 12°–15°/100 ft in 8 ½-in.- and 8 ¾-in.-hole-size sections. The system was tested under controlled conditions through variable rock strengths to ensure consistent and predictable build rates, as well as fine dogleg control for horizontal sections.

When sufficient test data had been gathered to prove the RSS was fit for purpose, it was then released for initial field testing on shale gas wells in North America.

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