Coupling Mechanism Between Carbonate Reservoir Development and Hydrocarbon Accumulation in the Yingshan Formation of the Tuoputai Area

This study examines the relationship between diagenetic evolution and hydrocarbon inclusions in Ordovician Yingshan Formation carbonates from Well Tuoying 1, Tuoputai area, Tahe Oilfield, using petrography, cathodoluminescence, micro-fluorescence spectroscopy, Raman spectroscopy, and fluid-inclusion microthermometry. Three calcite generations, two dolomite generations, and several fracture-filling relationships are described. Four fluorescence-defined oil-inclusion populations (orange yellow, yellow, yellow green, and blue green) and three temperature-defined groups of gas-associated aqueous inclusions are recognized. These populations provide evidence of heterogeneous hydrocarbon-fluid histories but cannot, without independent age constraints and demonstrated fluid-inclusion assemblage relationships, be equated unequivocally with four separate oil-charging events and three gas-charging events. Regional tectonic evolution and previously published burial-history interpretations provide a possible geological context rather than direct ages of inclusion trapping. The anomalously high homogenization temperatures measured for some hydrocarbon inclusions warrant assessment of pressure effects and post-entrapment modification before attribution to hydrothermal pulses. Because the new observations come from one well, regional implications remain tentative.