Project

Discipline

seismic; imaging; laboratory; modeling; waveform; inversion; anisotropy

Lead
Lay summary
This project seeks to develop new high definition seismic imaging techniques for visualising  subsurface structures by utilizing the full waveform information contained in the recorded seismograms. Such waveform inversion procedures should substantially improve knowledge about the Earth in the upper few kilometres. It will be innovative because it will take into account complexities such as anisotropy and poroelasticity of the rocks which are frequently ignored. The new numerical simulation and reconstruction procedures will offer considerable computational efficiency and accuracy over current techniques. The improved capacity to more realistically model and map geological structures remotely will have economic benfits for resource exploration and extraction, through better imaging of hydrocrabon reservoirs, coal seams and mineral deposits.  A distingusihing feature of this project is to construct an ultrsonic laboratory scale model facility, which can be used to simulate  a variety of interesting structures. The data obtained from the model experimenst will be analysed and inverted to assess the resolution limits and reliability of the images. The scale model system will also be used to study various aspects of wave propagation, especially the waveguiding effects of low velocity layers such as gas reservoirs and coal seams. The goal is to exploit such characteristics and build low cost, novel acoustic imaging systems for fault delineation, which is critical in petroleum field development and coal mining.

Direct link to Lay Summary

Last update: 21.02.2013

Title	Year

Number	Title	Start	Funding scheme

This project has as its primary goal the development of the next generation of seismic imaging capability for mapping the subsurface remotely. The application is mainly towards resource exploration and development where material anisotropy and poroelasticity are prevalent, but often overlooked in current seismic imaging strategies. The plan is to utilize the full waveform information contained in the seismograms so as to obtain high resolution images of complete elastic properties. For reasons of computational tractability the full waveform inversion algorithms to be devised will be 2.5D, which means the geological structure is assumed to be two dimensional but the wave propagation is three dimensional. The project will build on our considerable past experience and accomplishments in seismic exploration, which include contributions to modelling, inversion, imaging, instrumentation and field procedures. A distinguishing feature of this proposal is to construct a two-dimensional ultrasonic laboratory model facility, which can be used to simulate a variety of interesting and relevant geological structures. The data obtained from the model experiments will be analysed and inverted to assess the resolution limits and reliability of the new algorithms. The scale model system will also be used (along with numerical modelling) to investigate a variety of problems in seismic wave propagation, especially the waveguiding effects of low velocity layers such as gas reservoirs and coal seams. The goal is to exploit such characteristics and build low cost, novel imaging systems for fault delineation, which is critical in petroleum field development and coal mining. The new full waveform elastic anisotropic inversion code will also be applied to field data to be supplied by collaborators from industry, as well as to data we have collected ourselves in the recent past in connection with near surface investigations for engineering and environmental projects. Supporting theoretical and numerical model studies will be undertaken to help interpret the field data and to compare with the laboratory experiments.Given the challenge and scope of the project, it will be necessary to hire two PhD students and one postdoctoral fellow. One student will have primary responsibility, along with a technician and the postdoctoral researcher, for assembling the laboratory modelling system and electronics and performing the physical model experiments. The other student, along with the postdoc, will concentrate on developing the full waveform anisotropic inversion scheme and testing it against the laboratory models and other simplified algorithms. The two students, together with the postdoctoral fellow, will perform the field data inversions. The project has the potential to revolutionize the way the subsurface can be visualized with sound and the resulting images interpreted in a more meaningful manner.