Research on diagenetic facies of Chang 6 reservoir with low permeability in the Panguliang region of Ordos Basin

Using a series of analytic techniques,including polarized light microscope,scanning electronic microscope,X-ray diffraction,Fluorescence,and paleomagnetism etc.,eight diagenetic facies were recognized in the Chang 6 reservoir in the Panguliang area,and the reason of low permeability and porosity was discussed.The sand body of the Chang 6 oil reservoir is subdivided into eight diagenetic facies: strongly compacted biotite facies,carbonate cemented facies,authigenic chlorite cemented facies,chlorite coat remnant intergranular pore facies,chlorite coat remnant intergranular pore-feldspathic solution facies,kaolinite cemented facies,feldspathic corrosion facies,and laumontite and feldspar solution facies,respectively.Central part of the main sand body-characterized by the latter three facies has good oil-bearing properties,thus favorable for hydrocarbon accumulation.