Author:
Paul Jukes, PE, PhD, MBA, CEng | Director of Engineering | paul.jukes@pondco.com

Thousands of feet underwater, at depths where sunlight can’t reach, subsea systems sprawl across the ocean floor to extract oil from hard-to-reach reservoirs. These complex, interconnected systems are made possible by advanced design, engineering and analysis. 

What is a subsea production system?

Located on or below the sea floor, subsea production systems extract petroleum from reserves buried beneath the seabed. A typical subsea development is composed of wells, Christmas trees, manifolds, flowlines, risers and umbilicals. 

A Christmas tree is a large, complex assembly of valves and gauges that controls the flow of oil and serves as the primary interface between the well and the flowlines. When a new well is drilled, the extracted oil flows out at extremely high pressures. The tree valves open and close to regulate the flow of oil and allow it to be transported through a flow line. This leads to a processing facility before being distributed for consumer use.

The engineering required to build this intricate network of underwater infrastructure must be calculated, precise and capable of withstanding extreme operating conditions. Hard-to-reach oil can be buried deep under the ocean where temperatures are below freezing, and pressures often exceed 10,000 psi. 

Being able to safely install a production system requires a thorough understanding of the conditions of the seabed to avoid improper installation, overload, buckling, corrosion, or any other conditions that would cause the system to fail. The farther underwater these systems go, the greater the strain each of its parts is susceptible to. 

How subsea developments are pushing the engineering envelope

Subsea infrastructure requires extremely careful planning, design, engineering and analysis. Moving production underwater means engineers must get creative with finding solutions to problems that emerge more than 10,000 feet below the sea. 

Engineers use advanced engineering analysis tools to completely understand a system’s parts before being submerged. Finite element analysis (FEA) is one method used to simulate how a part may behave when exposed to extreme pressures or temperatures. 

FEA can be used to undertake local solid modeling of complex subsea components such as bulkheads, flanges, field joints and spiral pipes. Constructing FEA models efficiently and quickly is the key to efficient design iterations leading to an optimized economical design. Leveraging advanced mathematical modeling can aid in structural analysis, heat transfer, fluid flow and transmission.

Geotechnical engineering tools analyze soil, geohazards and possible seismic activity on the ocean floor. The hardware that interconnects with the risers and flowlines is set in place using sophisticated anchoring systems designed to withstand the harsh conditions of the seabed. These systems utilize cutting-edge materials and innovative designs to ensure stability and longevity in the challenging marine environment.

Given their locations, subsea developments rely on autonomous technologies to enhance efficiency and reduce the need for human intervention. Remote monitoring and control systems enable operators to manage subsea production assets from onshore or offshore facilities, improving safety and operational reliability.

Using advanced engineering to address the industry’s most difficult challenges

Deep water, high temperature, and high-pressure systems can be installed through the use of advanced engineering and analysis. The advanced analysis tools allow for the design to be optimized in a way that is not possible using traditional calculation methods. 

Pond’s subsea group has advanced analysis tools developed in-house to design and optimize subsea pipeline systems. Using these tools, subsea production systems can be designed at depths as far as 12,000 feet and temperatures up to 350 degrees F. They can also be used for cryogenic applications where temperatures are -265 degrees F.

These calculation tools are highly complex, involving things such as material nonlinearity, large displacements, and pipe-soil interaction. This type of analysis can be used to undertake span analysis, lateral buckling and reeling analysis. These tools play a pivotal role in optimizing designs, and ultimately save costs in engineering. 

Through advanced analysis tools, the challenges of deepwater and high-pressure and high-temperature systems can be addressed by integrating these tools with pipeline design methods, such as limit state-based design. If pipelines are designed using this approach, optimized wall thicknesses can be obtained, resulting in significant financial savings when undertaken correctly.

Balancing demand and decarbonization

As a leader in the energy sector, Pond is committed to supporting the transition to decarbonization. We optimize the extraction of hydrocarbons using advanced tools while integrating sustainable practices and pioneering new technologies, thus contributing to a carbon-neutral future. 

The demand for hydrocarbons has created the shift from primarily onshore extraction to deeper fields of exploration. While hydrocarbons continue to meet the world's energy needs, the goal of reducing greenhouse gas emissions necessitates a transition to cleaner energy sources. 

Transitioning to a carbon-neutral energy sector involves not only increasing the share of renewable energy but also implementing carbon capture, utilization, and storage (CCUS) technologies to mitigate emissions from remaining hydrocarbon use. 

The balance between meeting energy demand and decarbonization objectives requires strategic planning, technological innovation, and international collaboration to achieve a carbon-neutral energy landscape by 2050.

About Pond

Pond is a full-service architecture, engineering, planning, and construction management firm with both onshore and offshore pipeline design capabilities. Our offshore and subsea group has extensive experience and in-depth knowledge of subsea engineering and can provide services for the complete life cycle of an offshore project, from pre-front end engineering and design (pre-FEED), FEED, detailed design, procurement/fabrication support, installation support, commissioning support, operational support, and decommissioning. For subsea development, Pond covers subsea umbilicals, risers and flowlines (SURF), rigid pipelines, structures, subsea hardware and advanced engineering. Learn more about Pond's subsea capabilities here.