This paper documents the success story of the first quadlateral completion for an Alaskan operator by use of stacked, rotatable, Technical Advancement for Multilaterals Level-3 junction systems. This well is also the first in the world in which the junction system is stacked more than twice in a single well. This quadlateral completion design is the product of targeting multiple formation layers from a single wellbore by use of openhole horizontals with slotted liners. The rotatable, multilateral junction system accommodates the increased number of laterals necessary for continued economic exploitation of the West Sak heavy oil reservoir.
Mechanical problems with one of the original West Sak dual-lateral wellbores led to the planning of a replacement well in 2015. The well is a quadlateral that replaces the D-sand lateral in the original dual-lateral pattern as well as incrementally developing the underlying A sands in this same pattern and the adjacent pattern to the north. Limited surface well-slot availability and opportunities to pursue similar well designs in future projects led to the decision to pursue a quadlateral design.
All laterals are oriented south to north, drilling down structure approximately 80 ft true vertical depth subsea from heel to toe. As planned, all laterals crossed a 30-ft down-to-the-north fault without issue. A deep resistivity geosteering tool was used for all laterals to improve time in zone and avoid concretion-prone layers.
The parent well was landed in the A2 sand and has a lateral length in zone of 6,364 ft. The A3-sand lateral was only 3,529 ft long, to avoid potential encroachment from an oil/water contact to the east. The A4 lateral was the longest at 7,147 ft in zone. The D-sand lateral was limited to the original pattern and had 4,557 ft in zone. All A-sand laterals were drilled directly under the original dual-lateral’s well path. The D-sand target line was drilled 150 ft east of the original injector spacing....
Quadlateral Success Story in a Heavy-Oil Reservoir
18 August 2016