Pore types and controls of Silurian reservoirs in Sanshun area, Tarim Basin

High-quality reservoirs in the Silurian Kepingtage Formation play an important role in oil and gas exploration in the Sanshun area of Tarim Basin. The reservoir rock characteristics, pore type and pore evolution stage of the Kepingtage Formation were studied in detail using core analysis, thin section observation, cathode luminescence, ESEM, EDS, and inclusion temperature. The controls of high quality reservoirs were identified and combined with sedimentary and diagenetic analyses. The research suggested that lithic sandstones with low compositional and textural maturities were deposited in the low-energy muddy nearshore of the lower Kepingtage Formation, and then strongly impacted by compaction. Hence they were dominated by residual intergranular pores. Reservoir properties were controlled by sedimentary facies and compaction. Porosity in the sandy shore sand in the upper Kepingtage Formation was well connected laterally and longitudinally. Dissolution improved reservoir properties, and the last phase of secondary dissolution contributed greatly to reservoir quality.