New Technologies and Methods for Ultrahigh and High Resolution 3D Seismic Characterization of the Shallow Subsurface

This project aims to develop new three-dimensional (3D) high-resolution imaging solutions for characterization of the shallow subsurface in fjords and coastal environments. The current market for shallow subsurface imaging is dominated by high-resolution two-dimensional (2D) technologies. As a result, geological and geotechnical models used in the marine infrastructure industry are based on grids of 2D data. This approach introduces uncertainties to the subsurface models due to the inherent limitations of describing 3D features with 2D data. In order to overcome these limitations, this study will develop tailored imaging solutions for high-resolution 3D characterization. Implementation of such technology allows for mapping of smaller features like boulders and soft layers, provide better correlation with core data and use of data driven 3D inversion of subsurface properties. Marine infrastructure projects will benefit from the improved subsurface models in form of added flexibility, cost effectiveness and safety. The study takes a multi-disciplinary approach that includes development of seismic acquisition equipment in addition to optimization of processing and interpretation methods for high-resolution 3D imaging. The new technologies and methods build on proven techniques from the oil and gas industry. A central part of the development includes the design of a new acquisition system using the P-Cable 3D seismic system of UiT The Arctic University of Norway. The results of the study will give users in both industry and academia better tools for integrated interpretation of the shallow subsurface.

Subsurface imaging is crucial for a range of applications such as oil and gas exploration, evaluation of geohazards, and characterization of the shallow subsurface for infrastructure projects. Seismic reflection surveying is a geophysical method that images the subsurface along two-dimensional (2D) profiles or in three-dimensional (3D) volumes and is commonly used to obtain such information. Conventional 3D seismic, which has a vertical resolution of 10’s of meters, is the industry standard for exploration and development projects in the oil and gas industry. It is preferred over conventional 2D seismic due to its higher resolving power. In contrast, high resolution (HR) and ultrahigh resolution (UHR) seismic surveys, used for meter to sub-meted scale imaging in site characterization, are dominated by 2D technologies such as sub-bottom profiling and HR 2D seismic. This limits our spatial understanding of the subsurface, which in turn results in considerable uncertainties in the interpretations. At present, no available UHR or HR 3D technologies combine a commercially viable acquisition efficiency with the descried UHR spatial resolution. The aim of this project is to develop new cost-effective UHR and HR 3D seismic imaging solutions tailored for characterization of the seabed and shallow subsurface. The research takes a multi-disciplinary approach and includes development of seismic acquisition hardware in addition to addressing current processing and interpretation methods in an effort to optimize them for UHR and HR 3D data. The results of the study will give users across industries better tools for imaging and interpretation of the shallow subsurface.