Design and Cost Optimization of Severe-Sour High-Pressure High-Temperature Deepwater Pipeline

Deepwater pipeline projects operating under severe sour, high-pressure and high-temperature (HPHT) conditions present some of the most challenging environments in offshore engineering. These pipelines must withstand extreme mechanical loads, corrosive fluids and complex seabed interactions while maintaining structural integrity and operational reliability throughout their design life. The combination of NACE Region 3 corrosive conditions (up to 5000 ppm H2S), HPHT parameters, and deepwater installation constraints demands a holistic approach to design and cost optimization that goes beyond conventional practices. Failure to address these challenges early in the project lifecycle can lead to significant scope changes, cost overruns, and operational risks. This paper examines the integrated strategies employed to optimize both cost and design for a severe sour HPHT deepwater pipeline system, starting from front-end engineering through fabrication and installation. Key focus areas include material selection for corrosion resistance, buckle contingency planning, as well as innovative and cost-effective solutions. By embedding critical requirements into the Engineering, Procurement, Construction and Installation (EPCI) contract, the project team aimed to minimize scope creep and ensure predictable delivery. These strategies collectively demonstrate how early recognition and proactive management of technical complexities can deliver a safe, reliable, and cost-effective pipeline solution in one of the harshest offshore environments.