Drill high-angle well in challenging formation
PDVSA planned to drill a well in Lagotreco field to drain the oil
reserves of the subunits of the Misoa formation. The reservoir, sandstone in
nature, consisted of cross-interbedded layers of hard and soft formations. The
section would be drilled in a high-temperature environment of 280 to 300 degF,
adding to the challenging drilling conditions. The well plan required drilling
an 8 1/2-in section while building angle from 41.5° to 45° in just 300
ft and keeping the azimuth at 230°. Past wells drilled in the same area,
but with different well configurations, needed motors to be run in order to
reach the desired inclination. The motors did not reach the desired
inclination. Needing a more efficient drilling system to tolerate the harsh
conditions and counteract the formation tendency to turn the system to the
right, PDVSA, together with Schlumberger, found a solution for the new well
design.
Use enhanced RSS with new pad actuation system to optimize
drilling
Schlumberger provided the PowerDrive Orbit RSS to drill the new slanted
well. The new push-the bit RSS increases the pad opening force allowing a
greater load of contact. The RSS pad actuation system provides the steering
efficiency necessary to resist the natural turning tendency within the section
and improves the tool response under demanding conditions, even when exposed to
high temperatures, interbedded layers, and severe stick and slip. The sealing
design of the RSS enables system flexibility, an appropriate feature for the
interbedded layers of hard and soft formations.
Achieve inclination, save time, and increase ROP
The PowerDrive Orbit RSS drilled 1,187 ft MD and was able to achieve the
desired inclination of 45° in 177 ft, reaching its goal 123 ft ahead of the
plan. The section was drilled in a single run, rather than two, and in just 4
days. This efficient operation, with an average ROP of 16 ft/h, saved PDVSA 8.8
days of rig time.
Together, the new well design, optimum bit design, enhanced drilling
fluid properties, and PowerDrive Orbit RSS proved to be a durable solution for
future wells within the reservoir.
