Synthetic CPT Preparation

Imagine having a cone penetration test (CPT) for any location in your offshore wind development. This would allow freedom to modify a wind turbine array layout without needing to launch a new operation to obtain geotechnical properties relevant for design and planning of the new locations.

That’s what is possible with a quantitative approach to ground modelling, utilising pre-stack seismic inversion to invert for bulk modulus, shear modulus and density. From this can be derived other geotechnical parameters like cone resistance, sleeve friction, bulk modulus and shear modulus.

Key points:

• Pre-stack seismic inversion can be used to predict elastic and geotechnical soil properties

• CPT prediction is very sensitive to seismic data quality so demands high-end processing

• RockWave teams evaluate & optimise amplitude variation with offset (AVO) and gather alignment that are critical for a synthetic CPT (sCPT)

RockWave’s people are experienced in amplitude vs offset (AVO) compliant processing, which is of paramount importance for pre-stack inversion, as the method exploits the variations in amplitude across the wavefield to estimate the elastic properties of the earth.

We teamed up with Arup, SolidGround, British Geological Survey and Inosys for the RVO Nederwiek project in 2024 to do exactly this, with RockWave being responsible for ensuring the reliability and value of the inversion by developing an AVO compliant 2D UHRS processing sequence.

The processing sequence must be carefully developed to sufficiently minimise acquisition related noise, ghost reflections, wavefield directivity, statics, multiples, all whilst simultaneously ensuring the preservation of geologically-induced amplitude in the recorded wavefield, with QC methods to monitor AVO trends at each key stage.

Contact us about how we can give your inversion the best chance of success.

Related services: UHRS Reprocessing; 3D UHRS, Depth Imaging, FWI