子北地区延长组长6储层成岩作用及对储层性质的影响

Reservoir Diagenesis of Chang 6 of Yanchang Group in Zibei Region and its Influence on Reservoir Quality

根据铸体薄片、扫描电镜、阴极发光等化验资料对储层成岩作用进行综合研究,研究表明:鄂尔多斯盆地子北地区的延长组长6长石砂岩储层处于晚成岩期阶段,成岩作用中压实作用、胶结作用和溶蚀作用对储层的孔隙结构有较大影响。早期压实作用和中晚期胶结作用致使该区砂岩成为致密型的储层,但早期形成的绿泥石膜反而保护了一些砂岩的原生孔隙,使绿泥石胶结的储层中发育残余孔隙,晚成岩期的溶蚀作用使绿泥石、长石、石英和方解石胶结物中发育溶蚀孔隙,从而在储层中形成次生孔隙发育带,构成了油气聚集的必要空间。

According to the reservoir comprehensive analysis and research of cast thin section,scanning electron microscopy,cathode luminescence,sandstone reservoirs diagenesis of Chang 6 of Yanchang group in Zibei region of Ordos basin is belonging to the late diagenetic stage. The main diagenetic compaction,cementation and dissolution,has a very strong influence to their reservoir pore structure. Compaction and cementation make the area a dense sandstone reservoirs,but the chlorite formed in early diagenetic stage protect some primary porosity sandstone and develop residual porosity reservoir. Strong dissolution of late diagenesis produce dissolution porosity in chlorite,feldspar,quartz and calcite cement,thereby form a pore zone in the reservoir,and constitute the necessary space for hydrocarbon accumulation.