Implementation of overlap degree in sphere packed sedimentary rock model and its impact to pore structure characteristics

Abstract

Computerized rock modelling is studied and developed because natural rock samples can sometimes be difficult and expensive to obtain. Sedimentary rock modelling is a process of generating a digital sedimentary rock model using numerical methods which resembles the ideas and processes of natural sedimentary rock formation. One of the most important physical characteristics in generating the model is how the pore structure is affected by overlap degree among each grain. The overlap degree simulates the output of compaction process in natural sedimentary rock formation. The approach to implement such idea is by using spherical grains so that the degree of overlap could exactly be determined quantitatively. Stochastic method is used in the algorithm to map each grain positions based on a desired range of overlap degree. From previous trials it shows that higher overlap degree produces lower porosity. The algorithm is implemented in generating two dimensional cross sections of the model as well as in generating three-dimensional structure. Characteristics of pore structure are analyzed for various modelling parameters to obtain better understanding of the modelling nature.