CHARACTERISTICS OF PORE STRUCTURE OF CHANG6 RESERVOIR IN WUQI AREA,ORDOS BASIN

The pore structure study is an important content of fine gas reservoir description and comprehensive reservoir evaluation. The microscopic pore structure of chang6 reservoir in Wuqi area was thoroughly analyzed and investigated by using of many technical means such as cast thin section, scanning electron microscope, cast image analysis, high-pressure mercury injection and constant velocity mercury injection, etc. The chang6 reservoir is characterized by high pore and low permeability. The main pore type of the reservoir is primary remained intergranular pore, the dissolution of the feldspar, the debris and early carbonate cement results in the secondary pore. The most reserved space is mesopore and macropore, and fine throat and midthroat is the basic seepage passage. Pore-throat image of thin-section shows that the reservoir chang6 has complicated pore-throat distributed character. Various pore-throat distributions of microfacies and various pore structure characters are important factors that lead to difference of oil-well productivity.