Drill challenging curve in large hole section
PEMEX was developing a horizontal well in a field near Villahermosa,
Mexico, and needed to drill a curve in the 12 1/4-in section. The drilling plan
called for a curve with a 78° inclination and 28°—22° azimuth
to allow the well to be landed in the Paleocene reservoir. Adding to the
challenge of developing this well, the field is characterized by high shock and
vibration and a narrow mud weight window. Wells drilled in this field require
heavy mud weight (greater than 14 ppg) to remain within the reservoir's mud
weight window. Maintaining this window is critical to avoiding gains or losses
that result in NPT.
To achieve its objectives, PEMEX needed an RSS capable of building
5°/30 m [5°/100 ft] to assure it could achieve the planned 3.6°/30
m [3.6°/100 ft] build. It would also need to be able to operate reliably in
heavy mud weight conditions, which typically present reliability and durability
issues for conventional RSSs.
Use PowerDrive Orbit RSS to drill curve and withstand heavy mud
Schlumberger experts recommended the PowerDrive Orbit RSS, which has a
pad actuation with metal-to-metal seals that withstand solids in the mud. Using
the IDEAS platform to model bit-rock interaction specific to the field,
Schlumberger determined that the SHARC bit would effectively manage shock and
vibration in combination with the highly reliable push-the-bit RSS.
Achieved shoe-to-shoe drilling of curve section
The PowerDrive Orbit RSS smoothly drilled the 12 1/4-in section from
shoe to shoe with an average dogleg severity of 3.6°/100 ft [3.6°/30
m], allowing the well to be landed on target. The RSS and SHARC bit reached
section TD 5.6 days ahead of schedule by withstanding heavy mud weight
conditions and effectively managing shock and vibration. This time savings
reduced operating costs by USD 300,000.
PEMEX plans to use these technologies to more efficiently develop future
horizontal wells, which are the trajectory type with the highest recovery rate
in the field. For this field, a typical horizontal well produces about 4,000
bbl/d with gas lift—1,500 bbl/d more than other types of directional
wells typically produce there.