Development and Installation of an Extended Reach Multilateral Junction

Abstract

Abstract A multitude of extended reach technologies have been utilized in the West Sak field on the North Slope of Alaska to reduce surface impact in a remote and environmentally sensitive area. Significant to the shallow heavy oil West Sak development is the use of multilateral horizontal wells with a junction providing mechanical support and both through-tubing lateral isolation and re-entry capabilities. However, as extended reach drilling capabilities evolved to routinely reach departure to true vertical depth ratios in excess of five to one, multilateral junction technology did not evolve at the same pace. A new multilateral junction was designed to match current extended reach drilling capabilities and replace existing multilateral equipment which was utilized beyond its intended limit incurring both installation and production risk. The newly designed junction allows lateral liners to overcome drag limitations by rotating the liner and junction to setting depth in one trip and includes several positive indicators to ensure a successful installation. This paper discusses the evolution of multilateral wells in the West Sak development, the limitations of multilateral junctions when utilized in extended reach wells, the development and testing of a new multilateral junction, and several successful field installations. Operation highlights during the completion phase of a multilateral well with a lateral departure to true vertical depth ratio in excess of six to one are included. Existing tools such as oil based mud lubricants and thorough torque and drag prediction were combined with the new junction for a successful completion which progressed the application for multilateral junctions in extended reach wells