ISO 19901-4:2016

Overview

ISO 19901-4:2016 - Petroleum and natural gas industries: Specific requirements for offshore structures - Part 4: Geotechnical and foundation design considerations - provides guidance for geoscience and foundation engineering applicable across a broad range of offshore structures. The standard covers site and soil characterization, identification of geohazards, design and installation of shallow and pile foundations, soil–structure interaction for auxiliary subsea systems, and anchors for stationkeeping of floating units. It complements other parts of the ISO 19901 series (see Related Standards).

Key topics and technical requirements

• Geotechnical data acquisition & hazard identification
  • Shallow geophysical surveys, geological modelling and assessment of hazards such as earthquakes, faulting, seafloor instability, scour, shallow gas and seabed subsidence.
  • Guidance on testing, instrumentation and selection of characteristic soil property values.
• Shallow foundation design
  • Principles for action transfer, idealization of foundation area and acceptance criteria.
  • Stability checks: bearing capacity, sliding and torsion; serviceability limits including settlement and rotation.
  • Special design considerations for hydraulic stability, installation, retrieval and removal.
• Pile foundation design
  • Axial and lateral capacity methods, skin friction and end bearing behavior in cohesive and cohesionless soils, grouted and belled pile considerations.
  • Pile group behavior, axial/tension performance, cyclic loading effects and representative soil–pile interaction curves (t–z, Q–z, p–y).
• Pile installation assessment
  • Drivability studies, achieving required penetration, refusal and remedial measures, hammer selection and driving stresses, drilled/grouted pile practices.
• Soil–structure interaction & anchors
  • Design guidance for subsea production systems, risers and flowlines.
  • Anchor design principles for stationkeeping and mooring systems of floating structures (informative guidance provided).

Practical applications and users

ISO 19901-4 is intended for:

• Offshore geotechnical and foundation engineers designing platforms, jackets, gravity bases, piles and anchors.
• Structural engineers and designers integrating foundation performance into offshore structural design.
• Survey and site investigation teams planning marine soil investigations and geophysical surveys.
• Installation contractors, drilling teams and asset owners assessing drivability, installation risks and long-term performance.
• Regulators and project managers requiring consistent geotechnical design practices for petroleum and natural gas offshore projects.

Related standards

• ISO 19901 series (other parts addressing specific aspects of offshore design)
• ISO 19901‑8 - referenced specifically for detailed requirements on marine soil investigations.

This standard is essential for ensuring safe, durable and code-compliant geotechnical and foundation solutions in offshore oil & gas developments. Keywords: ISO 19901-4, offshore geotechnical, foundation design, pile foundations, shallow foundations, soil-structure interaction, mooring anchors, petroleum and natural gas.