Home / News / Petroleum Development Oman makes RSS work in low-cost environment

Although hydrocarbon basins in Oman are located in the desert, where rig rates and spread costs are typically low, Petroleum Development Oman (PDO) has been able to make use of rotary steerable systems (RSS) in niche applications, said Moataz Riyami, well engineering delivery team leader for the thermal cluster at PDO, during a presentation at the IADC World Drilling 2008 Conference.

Rotary steerables can drill both straight and curved sections while rotating, unlike drilling motors, which have to be slid when drilling a curve. The elimination of sliding can solve many problems:

Petroleum Development Oman makes RSS work in low-cost environment

  • • Maintaining tool face orientation.
    • Slow sliding, or inability to slide.
    • Poor hole cleaning when sliding.
    • Poor hole quality from rotating motor bend.
    • Borehole tortuosity and spiral.

In order to be sure that each rotary steering application made economic sense in the low-cost environment, PDO developed screening criteria. These included drilling performance, value of information, drilling enabling and production. PDO also made sure that each application has a measurable performance metric that fulfills the operator’s requirements and is acceptable to the contractor. Incentive pricing was used based on, for example, dollar per meter drilled and a ROP bonus, for a performance drilling application on a deviated sidetrack. Or dollar per meter successfully logged on a trajectory control application to enable wireline logging.

In one case history that Mr Riyami presented, RSS was used for performance drilling in a deviated sidetrack. The closest directional well to the planned sidetrack was drilled with motors in a S-shaped hole. This S-section took 42 days to drill. In the new sidetrack, a point-the-bit rotary steerable system was used to drill the S-section, which took eight days to drill from 1,500 m to 3,000 m TVD. The ROP was comparable to offset vertical wells and considerably faster than the previous directional well. Drilling torque for the vertical section beneath the S-shape was reduced significantly as well.

Additional case histories related to this presentation will be detailed in the July/August issue of Drilling Contractor.

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