Petrobras Improves Well Placement Using RSS Technology and Gyrosteering Capability | Schlumberger
Tech Report
Brazil, South America, Offshore

Marlim Sul Field
Offshore Brazil

Openhole sidetrack

Deep water

Hole size
8 1/2 in

Unconsolidated Sandstone

Planned dogleg severity
3½°/30 m [3½°/100 ft]

Actual dogleg severity
5 1/3°/30 m [5 1/3°/100 ft]


The usual strategy adopted by Petrobras in the complex turbidite reservoir in the Marlim Sul field is to drill a pilot well to investigate the base and top of the reservoir followed by a sidetrack to gyrosteer inside the sandstone bodies. Because of the magnetic interference generated by the 9 5/8-in casing, a regular magnetometer-based RSS required spacing of approximately 15 m from the shoe to correctly orient the bit in the desired direction and start a sidetrack. This necessary spacing had the potential to lead to a complete exit of the sandstone body, jeopardizing the well placement.

Products Used

Petrobras Improves Well Placement Using PowerDrive Xcel RSS and Gyrosteering

PowerDrive Xcel RSS and GeoSphere service enable precise steering 1 m below casing shoe despite magnetic interference, deepwater Brazil

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The gyrosteering capability of the PowerDrive Xcel RSS enabled Petrobras to sidetrack just 1 m below the casing shoe, achieve the full deviation from the pilot well after 16 m, and build inclination from 82° to 85° with a dogleg severity of 5?°/30 m (even greater than the planned 3½°/ 30 m) despite magnetic interference caused by the 9?-in casing. GeoSphere reservoir mapping- while-drilling service enabled accurate drilling of an additional 866 m to achieve a total net pay of 643 m and exceed expectations for reservoir exposure.
Products Used

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