Faster ROPs in hot holes
  from: Offshore Engineer
  by: George Sutherland
  Thursday, October 02, 2008

When a major operator tapped Halliburton’s Sperry to drill a high-temperature field appraisal campaign in the UK North Sea, Sperry combined some of its Solar tools, increasing the ROP by 24% compared to offsets. Halliburton’s George Sutherland explains how it was done.

For the high-temperature field appraisal campaign in the central sector of the UK North Sea, Sperry Drilling Services opted to combine for the first time its Solar Geo-Pilot XHP 7600 series rotary steerable system (RSS) with the Solar quad-combo set of loggingwhile- drilling (LWD) tools. The combination offers faster rate of penetration, improved hole quality and more accurate wellbore placement to hothole environments for the first time. In this case, the combination yielded a 24% increase in the rate of penetration compared to offsets and also achieved all well objectives.

In the high-temperature North Sea field appraisal campaign, Sperry paired the Geo-Pilot XHP system with the quadcombo LWD set, comprised of ALD azimuthal lithodensity sensor, CTN compensated thermal neutron sensor, EWR-PHASE 4 resistivity sensor and BAT bimodal acoustic sensor.

Built and delivered specifically for the challenges of drilling this operator’s high-temperature wells, the Solar Geo- Pilot XHP system and LWD sensor combination performed flawlessly through real-time temperatures of 305°F (152°C) and recorded temperatures approaching 320°F (160°C).

Using the Geo-Span downlink software enabled surveying with pumps on, a considerable benefit when staging circulation for mud cooling could take more than five minutes at connections. In addition, to ensure the safety and efficiency of the HPHT operation, ADT drilling optimization service specialists offered 24-hour well monitoring of connection flow ECD and hydraulics management, plus vibration monitoring, which is essential for maintaining downhole tool reliability in high temperature environments.

With this combination of Sperry technologies, the customer obtained a 24% increase in ROP compared to motordrilled offset wells. In addition to a faster penetration rate, precise wellbore placement and improved hole quality, use of the Solar system technology allowed for real-time reservoir evaluation-whiledrilling. The real-time evaluation while drilling streamlined subsequent wireline logging runs, resulting in significant cost reduction and rig time savings.

The industry’s first high-temperature and high-pressure rotary steerable tool, Sperry’s Solar Geo-Pilot XHP point-the-bit RSS can withstand temperatures as high as 347°F (175°C) and pressures to 30,000psi; with survival temperatures up to 392°F (200°C). Testing of the Solar tools ensures operational reliability, as Solar assemblies are subjected to a specific temperature profile, which includes operational tests at 347°F (175°C) and nonoperational soaking at 392°F (200°C). The Solar suite of MWD/LWD sensors are rated to 347°F (175°C) and 25,000psi and were proven in nearly 600 hightemperature runs and more than 35,000ft of high-pressure hole last year.

The Solar tools provide accurate directional data in HTHP conditions for precise well placement, wireline-quality reservoir data while drilling and optimum log quality for effective, economic reservoir characterization.

The successful introduction of the Solar Geo-Pilot XHP system represents a forward-looking response to customers’ growing needs for drilling solutions in HTHP environments. OE

About the author
George Sutherland is Halliburton Sperry Drilling Services gobal business development and marketing manager. He has 22 years’ industry experience within directional drilling services, including positions in field operations, operations management, personnel, marketing and business development. Sutherland holds a bachelors degree in geology from The University of Texas at Austin.

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