Characteristics of fluid inclusions and hydrocarbon accumulation periods of Leikoupo Formation in western Sichuan Basin
Based on seismic,drilling,core and inclusion thin sections data,combined with regional tectonic evolution and hydrocarbon generation and expulsion processes of source rocks,this study analyzes the fluid inclusion petrology,uniform temperature and salinity measurement,burial thermal evolution history simulation,and gas reservoir evolution process analysis of the Leikoupo Formation reservoir in the western Sichuan exploration area.It clarifies the oil and gas filling time and period of the Leikoupo Formation,and analyzes the formation process of different types of gas reservoirs.The results show that the Leikoupo Formation inclusions in the western Sichuan exploration area develop in groups/zones after the filling period of pore minerals,with low abundance(GOI of 1%±),and are all gray-dark gray hydrocarbon containing saline inclusions;the uniform temperature is between 90℃～200℃,and the temperature peak is between 120℃～150℃;the salinity distribution is between 0～24%,which can be further divided into three intervals:0～4%,6%～18%and 20%～24%.There are three main periods of natural gas accumulation in the Leikoupo Formation of the western Sichuan exploration area,namely the Late Triassic,late Early Jurassic to early Late Jurassic,and Neogene Quaternary.The process of oil and gas accumulation is that the source rocks of the Longtan Formation of the Upper Permian and the Leikoupo Formation of the Middle Triassic entered the peak of oil generation in the Late Triassic,and the crude oil was generated along the faults formed by the Indosinian movement and entered the 4th member of Leikoupo reservoir to form an ancient oil reservoir;in the Early to Middle Jurassic,two sets of source rocks entered a peak of gas generation,superimposed with the cracking of ancient oil reservoirs to form oil and gas reservoirs;the source rocks of the Maantang Formation in the slope area entered the peak of oil generation and migrated laterally along the unconformity to the 4th member of Leikoupo reservoir,forming an ancient oil reservoir.Since the Neogene,oil and gas reservoirs have finally been adjusted and shaped into their current form.
Petrographic characteristicsUniform temperatureSalinityAccumulation periodAccumulation processLeikoupo FormationWestern Sichuan exploration area
万方数据
维普
