Mineralogy and Pore Structure Characterization of Lower Oligocene to Early Miocene Formations in Parts of Assam–arakan Basin, North East India.

In this study, reservoir rocks have been characterized by pore-scale measurements and mineralogical analysis of core samples, drill cuttings or crushed samples col-lected from Upper Assam and Mizoram, North East India. The mineralogical composition and pore types were examined using various laboratory techniques, like petrography under transmitted light microscope, field emission scanning electron microscopy (FE-SEM), X-ray diffraction and nitrogen (N2) gas adsorption. The variation in porosity and permeability was related to different factors such as rock composition, cement-ing, textural parameters, grain size and sorting, pores and pore throats. Mapping attributes like pore struc-ture, surface area, pore size distribution (PSD), pore orientation, connectivity and pore volume regulated fluid flow through the pore network, which provides significant variations in the reservoir properties. Pores were analysed from the image processing of FE-SEM photomicrographs, which were used to estimate poros-ity and generate the topology map. This information was further used to visualize pore connectivity in a 3D pore network model. Pore characterization from N2 adsorption analysis helped infer the pore structure, pore volume, and PSD in the reservoir rocks. The stud-ied samples have an excellent meso to macro pore net-work that is also supplemented by the derived pore network.