PDVSA Increases ROP 100 Percent and Saves 8.8 Days in Sandstone Reservoir

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.