85% faster data collection for nearshore island project

The challenge

The nearshore developer’s endgame is to build an asset, generally at lowest cost with minimal environmental impact and generate some form of return on investment in the shortest possible time frame. Geo-risks arising from weak strata, cavities and variable geotechnical conditions arise from uncertainty in the surface and subsurface, so the ground can be a significant hindrance to developers meeting their engineering business ambitions. Unmanaged geo-risks are known to negatively impact project cost and schedule during construction and sometimes as a worst case, during asset operations. In addition, shallow nearshore environments are typically challenging to investigate and acquire the necessary data to manage geo-risks leading to a data gap: a lack of information relating to the surface and subsurface can lead to overly conservative design and CAPEX spend, the opposite of value engineering.

So, developments in the nearshore areas require a thorough understanding of seabed and sub-seabed characteristics to ensure economic and timely development and to minimise ecological disruption. However, investigating this challenging environment is not straightforward as traditionally, heavy assets such as jack-up rigs requiring extensive site effort are used to derive highly localised information that leads to an incomplete assessment of subsurface conditions.

The solution

Drawing upon our extensive nearshore expertise, our team proposed using seismic refraction, a technique that is widely used on land. This advanced geophysical technique involves studying the behaviour of seismic waves to uncover subsurface geological structures. Unlike conventional drilling, seismic refraction is non-intrusive and can be implemented with lighter assets. By generating seismic waves with an airgun and analysing the refracted signals, we could determine the depth and characteristics of subsurface layers, providing a far more detailed understanding of the area's geology and subsurface conditions that could be derived solely from conventional investigation and with minimal environmental footprint.

Key Benefits:

• Rapid data collection: a staggering 85% reduction in data collection time compared to traditional methods, saving valuable resources and time.

• Enhanced penetration depth: achieved deeper penetration of up to 20 metres, surpassing the capabilities of traditional methods.

• Accessibility: enabled exploration of previously inaccessible areas, yielding richer insights.

• Reduced environmental impact: the compact equipment and smaller vessels used minimised the environmental footprint and CO2 emissions.

• Optimised geotechnical scope: precise identification of drilling locations based on seismic refraction findings allowed for significant reduction and optimisation in geotechnical work, aligning with the island design objectives and minimising costs.

• HSSE risk mitigation: eliminated diver-related risks in data acquisition, enhancing safety and reducing HSSE exposure.

Impact

The deployment of seismic refraction for the artificial island project in the Middle East illustrates our commitment to providing innovative solutions that address our clients' complex challenges. By enabling rapid, accurate, and environmentally sensitive data acquisition, we not only accelerated the project timeline but also enhanced safety and reduced costs.