Pore Characteristics,Genesis,and Evolution Model of the First Member of the Canglangpu Formation from the Cambrian Series 2 in the Central and Northern Sichuan Basin
[Objective]In recent years,there has been a continuous exploration of the Canglangpu Formation from the Cambrian Series 2 in the central and northern Sichuan Basin,which exhibits substantial exploration potential. At present,the study of pores is relatively weak,restricting the in-depth understanding of reservoir development charac-teristics.[Methods]Based on the observation and identification of cores,cast thin sections,and cathode lumines-cence,image recognition software was used to obtain quantitative data of rock components and pore parameters. The pore characteristics,genesis,and evolution models of different lithological pores in the First member of the Canglang-pu Formation were studied.[Results]The results show that:the pore type of the First member of Canglangpu Forma-tion was mainly intragranular dissolved pores,which have the best positive correlation with the total face rate,fol-lowed by intergranular dissolved pores. The higher oolite/terrigenous sand content ratio is an important material basis for pore development,dissolution is the most favorable factor for pore development,and high energy shelf oolitic beach sedimentation is the key to the development of primary pores. The selective dissolution of atmospheric water in the syngenetic period is the key to the formation of the most important dissolution pores in oolitic sands in the First member of Canglangpu Formation,while the dolomitization in the quasi syngenetic and burial period enhances the compression resistance of rocks,reduces the solid volume,and increases the pores. The dissolution in the burial period is located along the fractures by tectonic disruption and early pores expansion. Terrigenous sand,cementation,com-paction,and pressure dissolution are not conducive to the development of pores in the First member of the Canglang-pu Formation.[Conclusions]Therefore,favorable carbonate components and subsequent diagenesis and tectonism have affected the development and evolution of pores and formed the lithologic sequence characteristics of the decreasing pore face rate:bright crystal oolitic dolomite,oolitic dolomite with sandy,sandy oolitic dolomite,fine-grained lithic sandstone,limestone,etc.
pore characteristicspore evolutionCanglangpu FormationSeries 2Cambriancentral and northern Sichuan Basin
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维普
