Schlumberger Drills First Slimhole Rotary Steerable Well

Schlumberger Oilfield Services announced a world first for the successful run of its slimhole rotary steerable system in the Shell Brent Delta field. On its first field test in the North Sea, the new Schlumberger PowerDrive Xtra 475 rotary steerable system successfully drilled 2377 feet in 43.5 hours with an average rate of penetration (ROP) of 67 ft/hr, making it the first known rotary steerable system successfully to drill this size of hole section.

"With the introduction of this new technology, we can now consider drilling wells previously deemed too complex," said Klaas van der Plas, senior well engineer, (New Technology) for Shell U.K. Exploration and Production (Shell Expro). "In this particular project, PowerDrive saved 8.42 days compared to drilling a typical 6 1/8-in. section."

The system comprised the PowerDrive Xtra 475 steering unit with the Vision telemetry system for transmitting data and a specially designed Schlumberger RS223 PDC bit. According to van der Plas, the well profile was quite complex, which required three-dimensional steerability to intersect multiple targets. "We experienced excellent steering response and hole quality, and were able to complete the job in a single run instead of several," said van der Plas.

The new PowerDrive Xtra 475 system allows for the most demanding of reservoir profiles to be drilled in a single run. With this new system, a well can be designed with a 6-inch hole as the primary reservoir section.

"Based on the outstanding field test results, our customers can look at new approaches to complex well designs," said Imran Kizilbash, president, Drilling & Measurements for Schlumberger Oilfield Services. "This unique capability, used in conjunction with real-time drilling and geological data, offers a distinct advantage to oil and gas operators to reduce well construction costs."