鄂尔多斯盆地超低渗透储层成因研究及意义

Origin of ultra-low permeability reservoirs in Ordos Basin and its significance

鄂尔多斯盆地超低渗透油藏资源丰富,但由于其储层物性差,非均质性强,导致开发难度加大。通过对沉积微相与成岩相的综合研究认为:在超低渗透储层背景下存在相对高孔、高渗区,三角洲前缘水下分流河道微相与辫状浊积水道微相碎屑分选较好,杂基含量较低,成岩早期压实胶结作用相对较弱,孔隙保存较好;成岩后期地下流体运动较活跃,溶蚀、溶解作用加强,为相对有利的储集相带。深入研究超低渗透储层的成因,对优选油气相对富集区,促进超低渗透油藏的有效开发提供了理论依据。

The resources of ultra-lowpermeability reservoir are abundant,but for the poor reservoir properties and strong heterogeneity,the development is difficult.According to comprehensive research of sedimentary microfacies and diagenetic facies,it is suggested that there are areas with relatively high porosity and high permeability in ultra-low permeability reservoirs.Due to the good clastic sorting,low content of matrix and poor compaction and cementation during the early diagenetic stage,pores can be well preserved.For the active fluid motion,intensive denudation and dissolution in the later diagenetic stage,delta front subsea distributary channel microfacies and braided turbidite channel microfacies are the favorable reservoir facies belt.This cognition is significant for optimizing hydrocarbon enrichment area and promoting economic development of ultra-lowpermeability reservoir.