School of Computer Science & Software Engineering

• about the School of  Computer Science and Software Engineering.
• about undertaking a research degree in the School.
• about The Univeristy of Western Australia, Perth, Western Australia.
• about scholarships at UWA
• about undertaking a PhD at UWA
  
• about the project from CSIRO
  

Background

Petroleum reservoirs are hosted in layers of sediments. In order to determine the best methods of extraction of the petroleum resources the heterogeneity of the sediments must be modelled. Due to high costs, there is typically only sparse data available for a reservoir and hence a high degree of uncertainty. By generating multiple stochastic computer models of a reservoir an engineer can determine a measure of uncertainty. Traditionally, geostatistical methods have been used to generate the models; however, this method cannot reproduce the complicated spatial structures found in many natural systems.

When a geologist creates a model of geological structure they base it on an analog model. An analog model is one that has been developed for a particular class of sedimentary environment, for example, a meandering river environment or a submarine channel system, and it will be based on accumulated information gathered from modern systems and surface outcrops of preserved ancient systems.

Our challenge is to encode the information that describes the analog model in a format that is both understandable to the geologist gathering and encoding the information and computer-friendly. For this we are using formal language theory.

Currently, we are experimenting with encoding the descriptions of sedimentary environment using probabilistic string grammars. We have developed a language that is capable of describing the sedimentary components and their spatial arrangements for simple patterns. However, as string grammars are inherently one dimensional their application to developing 3D models is limited. We are seeking a student who will build on this initial work by developing a higher dimensional grammar, such as a graph grammar, which is suitable for the project. The project also involves the development of a language parser that can generate stochastic sedimentary models from the grammars.

References:

E. June Hill, Cedric Griffiths, 2007. Simulating Sedimentary Successions Using Syntactic Pattern Recognition Techniques. Mathematical Geology, 39 (2), pp. 14—157. DOI 10.1007/s11004-006-9074-4

E. June Hill and Cedric M. Griffiths, 2008. Formal Description of Sedimentary Architecture of Analog Models for use in 2D Reservoir Simulation. Journal of Marine and Petroleum Geology, 25, pp. 131—141. DOI 10.1016/j.marpetgeo.2007.05.001

E. June Hill and Cedric M. Griffiths, in prep. Describing and generating facies models for reservoir characterisation: 2D map view.

"Handbook of Formal Language Theory", Vol. 1-3, G. Rozenberg and A. Salomaa (eds.), Springer Verlag, (1997)

Dora Giammarresi, Antonio Restivo, "Two-dimensional Languages", Chapter 4 in Vol. 3 of the above handbook, pp. 215 - 267