<![CDATA[The Permian to Triassic Tirrawarra Sandstone succession in the Cooper Basin of Cen-tral Australia is characterized by its low permeability. Ambient core porosity averages8.96% and ambient permeability 0.9 rnD. Most samples studied have permeabilities lessthan 3mD. Despite its overall poor resen’oir characteristics, the Tirrawarra Sandstone isone of the rnajor oil and gas targets in Australia. A total of 17 core plugs from 6 wellswere studied petrographically using optical petrography, SEM and XRD. These resultswere integrated with core analysis data. Petrographic study revealed the diagenetic events, rnainly mechanical and Chemicalcompaction, cementation and alteration have modified the reservoir quality. Ductile com-ponents such as rock fragments, clay and matrix influence mechanical compaction, whichare the main cause of resen’oir quality reduction. Quartz cementation and clay distribu-tion also affected the porosity, but particularly permeability. Mechanical compaction aswell as quartz cementation have reduced and blocked pore-throats to isolate intergranu-lar pores. The alteration of feldspar to kaolin has changed intergranular porosity tomicroporosity. Illite occurs as either cement, alteration of rock fragments or kaolinite. Aliof these diagenetic events also affect fluid movement in the resen’oir This paper presents the evaluation of the determination of effectiveness of porosity inthe delivery of gas from sandstone resen’oir in the Cooper Basin using integrated petrog-raphy analysis and core measurements. Key words: core porosity, core permeability, petrography analysis, diagenesis.]]>
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