Summary
High-pressure/high-temperature exploration activities in Kuwait include the
drilling of deep wells (approximately 16,500 ft) to search for high-quality oil
from the Jurassic formations. Recent discoveries of commercial gas and light
oil in six of the North Kuwait oil fields have resulted in the startup of the
North Kuwait Gas Development Project. This project is a major venture with a
planned production growth up to 1,000 MMscf/D of gas and 350,000 B/D of light
oil, which requires a total of more than 90 new wells. For this new phase of
development, the challenge was to change the approach to the drilling of deep
wells to reduce overall project timing and cost. A rethinking of current
drilling methods was required along with the application of new technology
solutions to optimize drilling times.
The North Kuwait deep-well design is complex and requires
surface/intermediate casings to be set at maximum depths to reach target depth
(TD) in a workable hole size. The 22-in. hole is drilled from 6,000 to 9,500 ft
and was considered to have a potential for improvement. A conceptual project
was set up that would attempt to replace multiple 22-in.-insert-bit runs,
rotary driven, with a single polycrystalline-diamond-compact (PDC) bit design
run on a downhole motor. The objective was to establish a partnership approach
with the bit manufacturer and motor provider and to develop bit designs,
equipment specifications, and operational parameters over the project
period.
The bit design team identified the main aspects on which the new PDC-bit
design was to be based, and a prototype bit was manufactured. Results from the
first run of the bit were analyzed, and the design was modified for the second
run. A critical element was the development of the downhole motor, with a
more-powerful 12 3/4-in. motor with precontoured stator being used for the
second and subsequent runs. Bit designs and downhole-motor and rig-equipment
specifications were developed and improved on over the project, resulting in
the achievement of the project goal with the drilling of the entire 22-in.
section with one bit from shoe to shoe. The performance improvements in the
trial wells gave substantial increases in rate of penetration (ROP) and reduced
drilling times.
© 2011. Society of Petroleum Engineers
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History
- Original manuscript received:
20 August 2009
- Meeting paper published:
25 August 2008
- Revised manuscript received:
3 June 2010
- Manuscript approved:
7 June 2010
- Published online:
11 February 2011
- Version of record:
11 March 2011
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