Applied Geomorphology and Geohazard Assessment for Deepwater Development

Abstract

Development of offshore hydrocarbon resources has in recent decades advanced into frontier deepwater regions around the world posing significant technical challenges for the design and installation of oil and gas wells and facilities. Development sites are typically remote and inaccessible and little is known about the seabed geomorphology and ground conditions to be encountered. Potential geohazards are at a larger scale than found onshore and include deep canyons and terrain highs, landslides and turbidity flows, faults, salt diapirism, gas/fluid expulsion, sedimentary bedforms and adverse soil conditions. Triggering events may include seismicity, volcanism, deep ocean currents and construction activity. Early acquisition and calibration of field-wide Autonomous Underwater Vehicle (AUV) high-resolution data is essential to ensure that development plans are not exposed to avoidable geohazard risks. A key element of the approach is the application of integrated geophysical, geomorphological and geotechnical methods that make best use of high-resolution data. This paper presents an illustrated approach for applied geomorphology and geohazard assessment for deepwater development that has been adopted by leading offshore oil and gas companies. Experience from major projects around the world demonstrates considerable value in the avoidance and de-risking of geohazards through comprehensive geomorphological assessment.