塔里木盆地轮南地区侏罗系砂岩储层成岩作用研究

Study on diagenesis of Jurassic sandstone reservoirs in Lunnan area,Tarim Basin

根据铸体薄片、扫描电镜、X-衍射、阴极发光及物性分析资料,结合前人研究成果,对塔里木盆地轮南地区侏罗系砂岩储层的成岩作用进行了综合分析,并确定了其成岩作用类型。对其成岩演化序列的研究表明:该储层已达到早成岩B期至晚成岩A期初阶段,并以晚成岩A期为主。早成岩A期,压实作用破坏了侏罗系砂岩的原生孔隙结构;晚成岩A期,长石颗粒强烈的溶蚀作用使侏罗系下统砂岩储层中发育溶蚀孔,构成了油气聚集的必要空间;伊利石、绿泥石、伊/蒙混层中发育的晶间微孔隙较大程度地改善了侏罗系中、上统砂岩的储集性能。

Based on cast slice,scanning electronic microscope,X-diffraction,cathodoluminescence and physical properties,combined with previous researhes,the diagenesis of Jurassic sandstone reservoirs in Lunnan area,Tarim Basin is analyzed,and the types of diagenesis are defined.The study on diagenetic evolutionary series shows that the diagenetic evolution of Jurassic sandstone has already been in B stage of early diagenesis to initial period of A stage of late diagenesis,with the latter being the majority.Compaction destroyed the primary pore structure of Jurassic sandstone intensively.The strong dissolution of feldspar particles at the A stage of late diagenesis made the dissolved pores develop in Lower Jurassic sandstone reservoirs,which constitutes the necessary space for oil and gas accumulation.The intergranular micropores developed in illite,chlorite,illite-smectite mixed-layer greatly improved the reservoir performance of Middle and Upper Jurassic sandstone.