Study on Shale Gas Fluid Flow in Porous Media

Extraction of shale gas which is categorized under unconventional reservoir is still remain a challenge for oil and gas industry in both technical and economical aspect. The reason being is shale possess nanopore size and this causes the difficulty for the flow of shale gas to wellbore from porous media. One of the problem faced at present is shale gas fluid flow has not been well understood and lack of this knowledge can affect the extraction and production of shale gas. Compared with conventional reservoir, the fluid flow can be described by using Darcy law. However Darcy law is not applicable to describe the fluid flow in nanopore size reservoir. Hence, this research is aimed to study and investigate the fluid flow mechanisms in shale formation. Few mathematical models from published research papers which are used to describe the shale gas fluid flow in porous media have been considered in this research. Amongst the types of non-darcy fluid flow mechanisms in shale are free gas flow, adsorption-desorption and diffusion were studied in details. Xiong et al. Model was selected and was applied to examine the apparent permeability for three different scenarios which including non-darcy flow, adsorption and surface diffusion. Sensitivity analysis of this research was presented in spreadsheet form to show the effect of the parameters on apparent permeability. There are two outcomes from the sensitivity analysis in this work. The first outcome is apparent permeability increases when pressure reduces, temperature increases and bigger pore size. The second outcome is apparent permeability with consideration non-Darcy flow only is the highest followed by apparent permeability that includes non-Darcy flow, adsorption effect and surface diffusion and finally is apparent permeability with non-Darcy flow and adsorption effect. In addition, comparison between conventional reservoir and shale gas reservoir in terms of gas generation, gas storage mechanism, produced gas types, production rate and recovery factor have also been included in this research.