Methods to assess and predict gas reservoir producibility

This project will look at developing improved methods to assess and predict gas reservoir producibility, and will look at conventional and unconventional reservoir rocks. The study will attempt to elucidate the structure-transport relationship for gas reservoir rocks. It will use novel experimental techniques such as integrated gas sorption and mercury porosimetry combined with computerised X-ray tomography. It will also look at utilising NMR methods, such as NMR cryodiffusometry, which allows the influence of differently-sized pores in the network on overall mass transport fluxes and void space accessibility to be determined. The fluid in a void space has freezing and melting point depression that depends on pore size. Hence, since small pores melt first, the ever larger pores in the network can be progressively melted and the resulting change in the mass transport rates in the molten fraction monitored by pulsed-field gradient NMR. Further, xenon is the same size as methane and can thus be used as a model for it in hyperpolarised xenon magnetic resonance imaging studies of gas flows in rocks. Imaging studies allow the contributions from larger length-scale features, and spatial heterogeneity in void space structure, to mass transport and accessibility to be assessed. Hyperpolarised xenon NMR spectroscopy can also be used to probe micropore network structure.