摘要：The aim of this research was to evaluate petrographic characteristics of the Tertiary Surma Group sandstone reservoirs. The diagenetic constituents, processes and their impacts on reservoir quality were evaluated. A total of 33 core samples collected from 8 different wells located in 7 different gas fields of Bangladesh were used for the current study. The standard petrographic microscope, scanning electron microscope (SEM/FESEM) and XRD were used in the current study. The framework grains, mineralogy, matrix, pore properties and cements were identified and counted properly. The framework grains were in accordance to dominance quartz (76-91%), rock fragments (5-16%) and feldspar (3-14%). The identified important diagenetic components were quartz cements, authigenic clays, carbonate cements and dissolution. The early to intermediate stage of the diagnostic realm was estimated in the studied samples, e.g., mechanical compaction, chloritization, carbonate precipitation, dissolution, quartz overgrowth and authigenesis of clays. The reservoir quality was not much affected by the effects of diagenesis. However, it seems to be controlled mostly by the mechanical compaction including its grain size, sorting and fabric. In addition the authigenic cements slightly modified its porosity and permeability status during diagenesis. The measured average thin section porosity and its permeability suggested good to excellent reservoir quality for hydrocarbons.
关键词：Petrography; Diagenesis; Surma Group; Sandstone; Reservoir Porosity; Permeability
