Abstract

Object-oriented software design has provided many benefits to the development of scientific software by encapsulating the attributes and behaviour of models into separate entities or objects that can interact with other objects in the software project. Objects communicate via message passing not by external reading and writing of an object's attributes. This results in more maintainable code since variables can only be modified by the object's own methods. Furthermore, inheritance creates opportunities for extensibility. Finite Element Analysis is a powerful tool for modelling heat and fluid transfer in, and the deformation of, complex shapes. The method achieves generality by allowing element definition to proceed to some extent without regard to the geometry of the problem. It is only after the elements are 'embedded' into the problem space that their geometry is set. This separation of element definition and general methods for solution of the global matrices suggests that the Finite Element Method can benefit from an object oriented structure. A more complex element can be created by inheriting properties from a simpler element and adding any specific behaviour. Thus elements can be designed to match specific problem requirements more easily. Much of the element's complexity is hidden from the rest of the program making overall development simpler. We present a prototype object oriented library for applying the Finite Element Method and analyse its general structure and its benefits. Finally, we present an example of its application to 2-dimensional heat transfer within a basin.

Introduction

Basin modelling is a process whereby exploration geologists investigate the hydrocarbon potential of a geological basin area. Oil and gas are produced when organic material is subjected to an elevated temperature over a sustained period of time. Once produced, hydrocarbons may migrate due to pressure gradients in the source rock to a new location in the basin, the reservoir. Basin modelling is a four fold process:

  1. Reconstruction of the basin geometry back through to the age that the sediments were deposited, (this involves determination of the structure at present day, removal and decompaction of the sediments to obtain the time-depth history of the sediments, and restoration of any blocks that may have moved along faults).

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