白豹地区延长组长3储层的成岩作用与成岩相

The diagenesis and lapidofacies of Yanchang formation Chang3 reservoirs in Baibao Area

目的探讨砂岩成岩作用阶段划分、成岩作用类型及其对储层的影响。方法根据铸体薄片、扫描电镜、X衍射、包裹体测温和镜煤反射率对储层进行综合分析和研究。结果鄂尔多斯盆地白豹地区的长3砂岩储层处于中成岩A期阶段,主要的成岩作用有压实作用、胶结作用和溶蚀作用,它们对储层孔隙结构具有很强烈的影响作用。结论强烈的压实作用和胶结作用使该区砂岩成为致密型储层,但早成岩阶段形成的绿泥石膜保护了一些砂岩的原生孔隙,从而使长3绿泥石胶结相储层中发育残余孔隙;晚成岩A期强烈的溶蚀作用使高岭石胶结相储层中发育溶蚀孔隙,从而在储层中形成孔隙发育带,构成了油气聚集的必要空间。

Aim To explore the division of diagenesis stage,the types of diagenesis and the effect of the reservoirs. Methods Based on the date analysis of casting iamella, scan electron microscope, X-ray diffractions and vitrinite reflectance,discuss and study reservoirs. Results The diagenesis include compaction, cementation and pressolution, which belong to the ＂A＂ late diagenesis and work on the Chang 3 reservoirs at Baibao area in Erduois Basin intensively. Conclusion Intense compaction and cementation make the sandstone changes to the tight sand, but the chlorite film preserves some primary pore at the early diagenesis and makes the relic pore in the chlorite cement facies of the Chang 3 reservoirs. Intense pressolution at the ＂A＂ late diagenesis also makes solution pore in kaolinite cement facies of those reservoirs. Those new pore bells now have shown the good prospect for oil and natural gas exploration in Eerduois Basin.