Smart Well Foundation, the Cost Efficient and Environmental Choice for Field Developments

This summary is based on the paper "Smart Well Foundation, the Cost Efficient and Environmental Choice for Field Developments," presented by Camilo Cardenas, Hans Erik Kolstrup Hansen, Sigvald Hanssen, Harald Blikra (Repsol Norge AS), Wolfgang Mathis, and Ole Kristian Holen (NeoDrill AS) at the SPE/IADC International Drilling Conference and Exhibition, 2021. The full paper can be accessed through the Society of Petroleum Engineers.

Essential Highlights

• CAN Technology Overview:

  • The Conductor Anchor Node (CAN) serves as a smart well foundation for rig-less conductor installation, integrating the conductor, manifold, and tie-in points, enabling early production and reducing project timelines.

  • The technology has evolved from simple conductor installation to the CAN-integrator, which supports wellhead systems and Subsea Production System (SPS) equipment.

• Operational and Cost Benefits:

  • Installing the well foundation before the rig arrives saves 2-4 rig days, with verified conductor load capacity in advance.

  • The approach reduces top-hole construction costs by 21-44%, equivalent to significant CO2 emission reductions (400-600 metric tons per well).

  • The well foundation’s smaller footprint and lighter weight compared to conventional structures simplify marine operations, reducing downtime and installation costs.

• Environmental and Safety Advantages:

  • The CAN-integrator minimizes environmental impact, with lower emissions across multiple categories, including climate change and human toxicity.

  • By enabling operations with smaller vessels and fewer campaigns, it contributes to reduced environmental footprint and improved safety.

• Flexibility and Integration:

  • The technology supports various levels of integration, from standalone well foundations to more complex systems with flow bases and trawl protection.

  • It facilitates flexible field development strategies, allowing for phased expansions and easy adaptation to changing project requirements.

• Accelerated Time to Production:

  • The CAN-integrator allows for early installation of flowlines and other infrastructure, decoupling drilling from flowline installation schedules and enabling quicker production start-up.

Abstract

The CAN® (Conductor Anchor Node) technology streamlines subsea satellite well production by integrating the well foundation, manifold, pipeline, and umbilical tie-in points, allowing for faster production start-up. By installing the well foundation with smaller marine vessels before the rig arrives, it reduces time delays and eliminates the need for large-scale drilling and cementing operations. This approach enhances efficiency, cuts costs, minimizes operational risks, and significantly reduces the CO2 footprint by 21-44%, or 400-600 metric tons.

Field-Proven Building Blocks

The presented strategy leverages existing, field-proven technologies by combining them in a more efficient way, using the well foundation for multiple purposes throughout different stages of the well lifecycle. The approach takes a holistic view of drilling, completion, and installation, integrating activities across the value chain and contract packages, such as drilling and SPS equipment, to optimize performance and cost-efficiency.

Well Foundation Technology

The well foundation technology, based on a suction anchor system, allows for rig-less conductor installation and has been successfully used in over 40 projects since 2006. Originally known as CAN-basic, it has evolved into the CAN-ductor, which integrates the first conductor joint and low-pressure wellhead housing (LPWHH) onshore. This method offers precise control over cement quality and is ideal for wells with shallow top reservoirs, enabling horizontal drilling in challenging conditions. The technology has demonstrated significant rig time savings and has been adapted for various seabed types, including sand and mixed layers. Life Cycle Analysis (LCA) has shown additional environmental benefits in its use.

SPS Equipment

The SPS (Subsea Production System) equipment, like the well foundation technology, is based on existing proven product lines, requiring only minor mechanical adjustments. The integration of SPS components, such as flow bases and protection structures, onto the well foundation occurs at the manufacturing yard before mobilization, reducing operational complexity. In 2021, pre-installed Permanent Guide Bases (PGB) were successfully deployed in the West of Shetland field development, moving processes from the rig to the onshore yard, resulting in cost, environmental, and operational efficiencies. Further integration of SPS equipment onto the well foundation is planned for future phases.

CAN-integrator

Definition

The well foundation technology bridges the gap between drilling and subsea facilities by providing a common platform for both wellhead systems and SPS equipment. This integration allows for synergies that optimize resource use, vessel campaigns, and costs. The subsea foundation, used for the conductor, also supports SPS components such as tie-in points, flow bases, and protection structures, creating lighter, cost-effective solutions. This approach delivers the same functionality as multi-slot templates while maintaining simple interfaces for integration. The first satellite development using this strategy on the NCS was the Equinor Bauge Field, installed in 2020 and tied to the Njord production facility.

Evolution of Integration

The integration of SPS equipment with the well foundation follows a stepwise approach, increasing in complexity and benefits. Initially, subsea trees are mounted directly onto the wellhead with flowline tie-ins, common in regions without trawl protection. Next, Permanent Guide Bases (PGBs) are mounted onto the conductor at the onshore yard, as seen in Field Development A, saving rig time by defining well heading during installation. Further integration involves adding Flow Bases (FBs) with tie-in porches, requiring more extensive interface checks and testing, especially when combined with trawl protection. The final step is fully integrating PGBs or FBs into the well foundation, creating compact, lighter, and cost-efficient structures with tighter interface tolerances.

Execution and delivery

The execution and delivery of the well foundation technology involves several key steps: engineering and detailed design, fabrication of the well foundation unit, integration of SPS equipment like PGB or FB, conducting System Integration Tests (SIT), and finally mobilization and installation via an offshore construction vessel. The well foundation’s delivery timeline typically runs in parallel with other SPS equipment, taking 6-8 months for systems with trawl protection and 4-6 months for those without. Project acceleration can be achieved if load capacity is verified through geotechnical studies, streamlining design and manufacturing.

Advantages

The well foundation technology provides several key advantages by serving multiple purposes throughout the well's lifecycle. It acts as a carrier for the LPWHH/conductor extension during vessel installation, provides a strong foundation for the wellhead system during drilling (handling high loads from BOP weight and riser tension), supports infrastructure such as tie-in points and protection covers, aids in fatigue and drive/drift-off mitigation, simplifies conductor cutting during P&A, and allows for optimized well placement, replacing multi-slot subsea templates.

Suction Anchor Based Well Construction

The suction anchor-based well foundation offers several technical and economic advantages. It allows the conductor to be installed by a vessel ahead of rig arrival, saving 2-4 rig days. The conductor's load capacity and verticality are verified before drilling, with an excellent track record of less than 0.2 degrees deviation. The system provides fatigue and drive/drift-off protection for the wellhead and supports slim well design, enabling early kick-off for highly deviated wells. It also simplifies P&A cutting operations, reduces the environmental footprint, and allows scheduling flexibility by decoupling drilling from marine construction activities.

Simplified Marine Operations and Project Schedule

The suction anchor-based well foundation reduces marine operation costs and vessel size requirements compared to traditional four-slot templates, requiring smaller crane vessels (150-250 mT) and simplifying installation. Its lighter, simpler structure lowers downtime, weather-related delays, and emissions, while enabling more efficient integration with other operations and independent manufacturing of tie-in lines.

Optimized Capital Expenditure (CapEx)

The well foundation building blocks offer a flexible field development strategy, reducing initial CapEx and development risks by allowing incremental well additions over time. Compared to traditional four-slot subsea templates, single well foundations have significantly lower costs, especially in early development phases. The approach minimizes upfront investment, enables daisy-chaining of satellites, and supports early production, making it a cost-effective solution for both greenfield developments and satellite expansions. Further cost savings can be achieved through vessel operations and optimized marine campaigns.

Accelerated Time to First Oil

The well foundation technology offers significant time-saving benefits compared to conventional subsea templates by allowing early installation of the foundation, wellhead, and PGB/FB. This enables flowline installation and drilling to commence sooner, decoupling drilling from flowline activities and accelerating the overall project schedule. Long lead items, like the subsea tree system, can be installed later, optimizing vessel and rig availability. In brownfield projects, similar advantages apply. The potential value of accelerated production is demonstrated by a scenario where 4 weeks of early production at 5000 bbl/day and $85/bbl can result in an additional $11.9 million in revenue.

Protection of SPS and Wellhead Equipment

The well foundation technology improves the protection of wellhead and SPS equipment by directly connecting protection structures to the foundation, rather than relying on traditional well load relief systems that add cost and complexity. This approach enhances wellhead fatigue life and strength while reducing costs. Additionally, it provides an efficient platform for tie-in points and protection structures, ensuring better protection against thermal fluctuations and fishing equipment impacts during production.

Optimized Well Placement

Optimized well placement using suction anchor-based well foundations offers greater flexibility in positioning wells, reducing the required step-out distance and mitigating geohazard risks. This approach shortens the well lengths, simplifying trajectories and decreasing drilling time, casing, cement, mud, and rig use. A study on a five-well development showed an average reduction of 600 m per well, saving approximately 3 km in total drilled length, which also contributes to lower emissions and reduced rig time.

Reduced emissions

The adoption of well foundation technology significantly reduces emissions in subsea developments, especially in categories such as CO₂ emissions, human toxicity, and acidification. Comparative studies on wells drilled in the UK and Norway show that using a suction anchor-based foundation instead of a conventional conductor cuts CO₂ emissions by 21-44%. Moreover, the integration of a closed-loop circulation system during surface casing drilling, combined with zero discharge processes, further diminishes environmental impact. This setup simplifies operational processes, reduces rig time, and contributes to overall emission reduction.

Summary

The CAN-integrator serves as a bridge between drilling, well operations, and subsea facilities, enabling optimized processes for hydrocarbon field or CO2 injection projects. This innovative well foundation approach reduces costs, CO2 emissions, and accelerates returns on investment by utilizing proven equipment in a new way. The technology shifts operations from rigs to smaller vessels, minimizing vessel campaigns, and contributing to a 21-44% reduction in CO2 emissions (400-500 mT) for the top-hole section of each well. Further emission reductions are expected with optimized vessel operations as future projects progress.

Reference

Cardenas, C., Hansen, H.E.K., Hanssen, S., Blikra, H., Mathis, W., & Holen, O.K. (2021). Smart Well Foundation, the Cost Efficient and Environmental Choice for Field Developments. SPE-209567-MS. Presented at the SPE/IADC International Drilling Conference and Exhibition. Retrieved from Society of Petroleum Engineers.