According to the genesis of the super-low permeability reservoirs in the Late Triassic Yanchang Formation in the central Ordos lacustrine basin

diagenetic sequences and homogenization temperature of host minerals of inclusions were analyzed.Hydrocarbon inclusions in albite were formed during the early charging in the early of the Late Jurassic;hydrocarbon inclusions in quartz overgrowth developed during the peak hydrocarbon generation and expulsion in the Early Cretaceous;while those in ferruginous carbonates were generated during the early phase of the uplifting and cooling process at the end of the Early Cretaceous and were the products of late charging.Taking account of current development characteristics of pores in the reservoirs

palaeo-porosity and palaeo-permeability of reservoirs during the peak hydrocarbon generation and expulsion were discussed.It is proposed that the super-low permeability reservoirs had not been developed during the peak hydrocarbon generation and expulsion

and that cementing of ferruginous carbonates is the crucial factor for the compacting of reservoirs.