CAJ | 학술논문

碳酸盐胶结物是鄂尔多斯盆地东南缘长8油层组最重要的自生矿物,主要类型为铁方解石,另有少量的白云石和铁白云石。镜下观察、包裹体测温、碳氧同位素分析及铁氰化钾染色实验分析证实,方解石胶结作用从早成岩阶段持续到晚成岩B期。早成岩阶段形成少量的无铁方解石,到晚成岩期,因有机质在热催化作用下脱羧而形成大量铁方解石。这种后期形成的铁方解石以半基底式—基底式胶结充填剩余粒间孔隙,大大降低了储层的储集性能。
탄산염효결물시악이다사분지동남연장8유층조최중요적자생광물,주요류형위철방해석,령유소량적백운석화철백운석。경하관찰、포과체측온、탄양동위소분석급철청화갑염색실험분석증실,방해석효결작용종조성암계단지속도만성암B기。조성암계단형성소량적무철방해석,도만성암기,인유궤질재열최화작용하탈최이형성대량철방해석。저충후기형성적철방해석이반기저식—기저식효결충전잉여립간공극,대대강저료저층적저집성능。
Carbonate cements are the most important authigenic minerals in Chang 8 reservoir in southeastern margin of Ordos Basin,and they are mainly ferrocalcite,with some dolomite and ferrodolomite.Based on thin slice and SEM inspection,inclusion enclave temperature measurement,carbon and oxygen isotope analysis and potassium ferricyanide coloring analysis,it is proved that calcite cementation started from the early diagenetic stage and lasted to the late diagenetic stage of B stage.In the early diagenetic stage,there generated light calcites,while to the late diagenetic stage,there generated a great quantity of ferrocalcites because of the organic material decarboxylation under thermocatalysis.Ferrocalcite generated in late diagenetic stage filled the remained intergranular pores with a semi-basal or basal cementation,which enormously lowers the accumulation capacity of the reservoir.