Vår Energi saves millions with industry’s first subsea retrofit multilateral wells

To rapidly increase production from the Goliat Field using existing subsea infrastructure, Vår Energi deployed RapidX™ TAML 5 high-strength, hydraulic-sealed multilateral junctions and transformed two single-bore subsea wells into multilateral producers with independently controlled branches.

Add oil production in challenging conditions

To boost production from the mature Goliat Field in the Barents Sea, Vår Energi wanted to reach different targets of the Snadd and Goliat West discoveries. However, the subsea infrastructure combined with the economics of low oil prices limited the options available to the company.

Reach new reservoirs without additional subsea infrastructure

Vår Energi engineers first reviewed the conventional option of drilling new wells. The field’s subsea templates had no open well slots, and the company wanted to avoid waiting 1–2 years for a new arctic-capable template, tree, or field flowlines. Mobilizing a modular offshore drilling unit added further timing and economic constraints to this option. All the wells in the field continued to produce, so plugging a well and then sidetracking was not an option.

Vår Energi and SLB decided that the best choice was to retrofit two existing wells as multilaterals. Each well would maintain production from its original bore while adding new production from one lateral. This option required multilateral technology with mechanical stability and hydraulic integrity. Furthermore, the completion would need to include a way to independently control each lateral so that reservoir contribution could be managed to balance production and ultimate recovery under the reservoir drainage program.

Retrofit two wells with field-proven multilateral technology

SLB recommended the RapidX junction with an intelligent completion enabling independent control of each lateral. The technology had been deployed in other locations but never before as subsea retrofits.

To mitigate the risks for this subsea development, SLB experts worked in constant collaboration with engineering teams from Vår Energi and its partners to optimize the final completion design and develop comprehensive procedures and contingency plans. COVID-19 restrictions began after the project was under way, adding the challenge of no international personnel mobilizations. In response, remote monitoring and other means of digital validation were used to verify the quality of some components and systems. System integration tests verified interoperability and functionality with third-party gauges and subsea trees.

Save time and capex while achieving accretive production

The new laterals were added to the existing wells, and the RapidX junction was installed and tested. Subsequently, the intelligent completion was installed and independent branch production initiated.

This operation enabled Vår Energi to avoid an estimated 5,000–10,000* metric tons of CO₂e emissions by eliminating the need to drill two new subsea wells and procure and install the associated infrastructure.

Technical details

For more information, read SPE-207960.

* The estimated emissions savings is based on assumptions regarding what the alternative field expansion solution would potentially be. The estimate’s main contributors are embodied sources and construction activities, for which we used The Inventory of Carbon and Energy (also known as the ICE database), the 2020 UK DEFRA conversion factors, and Mineral Products Association (MPA) Fact Sheet 18: Embodied CO2e of UK cement, additions, and cementitious material.