Published: 06/16/2011
Published: 06/16/2011
The 8 1/2-in sections of wells in Iraq's South Rumaila oil field are drilled through the Shuaiba formation, which is hard, compact limestone, and then into the Zubair formation, which is made up of shale, sandstone, and siltstone. Historically, these sections had been drilled with rotary BHAs, at a low ROP. The Rumaila Operating Organization (ROO) successfully increased drilling performance by using PowerPak XP extended power steerable motors in the 8 1/2-in sections. Schlumberger Integrated Project Management (IPM)—acting as project manager for ROO—wanted to further improve performance by drilling the section in just one run at a higher ROP.
Those objectives were achieved by drilling the section with a PowerPak ERT high-performance steerable motor, which has an even-rubber-thickness power section technology to deliver more than twice the torque output of conventional motors. The PowerPak ERT motor reduced stick/slip, provided higher differential pressures, increased average ROP over 36%, and improved drilling performance in the hard siltstone and sandstone of the Zubair formation.
IPM's use of the PowerPak ERT high-performance motor brought about a step change in performance compared to conventional drilling. The PowerPak ERT motor drilled the entire 8 1/2-in section in a single run with zero NPT—in 3 days less time than planned. At the usual Rumaila rig rate of USD 67,000 per day, that was a savings of more than USD 200,000. In addition, the fast drilling reduced the time the shale in the Zubair formation was exposed, so time-dependent shale swelling was not an issue during wireline logging and casing running. As a result of the shoe-to-shoe reliability it demonstrated, the PowerPak ERT motor was made the default choice for drilling the 8 1/2-in sections of future wells in South Rumaila field.
Challenge: Drill 8 1/2-in hole section in the South Rumaila field in one run at increased ROP.
Solution: Use PowerPak ERT high-performance steerable motor incorporating even rubber thickness technology.
Results:
