The microscopic pore structure studying on the chang 6 reservoir in yaodian oilfield,Ordos Basin

The feature of microscopic pore structure in chang 6 Reservoir of Yaodian oilfield in the Ordos Basin is researched based on the experimental technique of casting thin sections,scanning electron microscope and high-pressure mercury injection. The results show that,the lithology in this area is mostly arkose sandstone,Cement is mainly calcite,the chlorite is the main clay mineral component,the illite and illite / smectite mixed layer are the secondary clay minerals. Dissolved pores which are mainly intergranular dissolved pore and intragranular dissolved pore are the main pore types,Intergranular pore are the secondary pore types. The types of pore structure in study area can be divided into four types based on the capillary pressure curve shape and parameter characteristics,and the seepage ability gradually worse from class I to class IV. The characteristic parameters of pore structure analysis shows that,reservoir heterogeneity is serious,large pores have a big contribution to permeability and the small pores of reservoir provide greater storage space.