OEMG conducted an Aquares survey and prepared a ground model based on geophysics and targeted boreholes (early stage of the IDGM) for Mitsubishi-Talisman on the Daru Port expansion in Papua New Guinea.
Previous studies had been conducted over 2 years at significant cost, with 77 vibracores and 116 boreholes and extensive analogue surveys undertaken. Key project gaps were identified after the initial surveys were completed and no borrow areas were identified to supply fill material. There was also no understanding of dredge risk as boreholes were randomly assigned and not targeted to areas of potential geological risk.
OEMG conducted an Aquares survey including 600 line kms over just 10 days. Survey data was fully processed and provided to the vessel every 2 days to ensure that key areas were identified and adequately surveyed prior to demobilisation.
OEMG’s survey identified significant dredge risks and mitigation strategies were able to be developed, resulting in substantial reduction in dredge costs. There were also significant borrow areas identified to supply fill. 3D grids were developed to allow for volume calculations and 4D visualisations were provided in a GIS environment to improve decision making (early iteration of the IDGM).
The coloured areas and legend shows OEMG Aquares survey data which was collected in just 10 days. This shows that the channel proposed based on borehole and vibrocore data would have passed through rock rather than a paleochannel OEMG was able to identify to the east.
Project review: The cost of using un-targeted boreholes!
Millions of dollars in geotechnical and geophysical surveys that were inappropriate or un-targeted and as a result, failed to identify key risks or answer fundamental questions.
Significant loss of time and a requirement for redesign of key aspects of the project
A requirement to undertake expensive additional geotechnical surveys
In real terms:
2 years lost
No significant borrow areas identified for fill material resulting in project uncertainty
Many millions of dollars of latent geological condition claims and unforeseen project delays