Abstract:

Diagenesis and favorable diagenetic facies of Chang 8 reservoir in Heshui area, Ordos basin are researched using physical property analysis, mercury penetration, cast section and SEM  technique. The results show that physical property is poor, pore throat is minute, finemesograin feldspathic litharenite dominated, clastic constituents are complicate, compositional maturity is low and texture maturity is low to middle. Original pore spaces are decreased because of compaction, cementation damage not only partial primary pore but also secondary dissolved pore, dissolution improves the physical property. Five kinds of diagenetic facies are classified on the base of the influence of diagenesis on physical property. There is an intimate relationship between qualifying reservoir and diagenetic facies, physical property and oil bearing  of chlorite cementationfeldspar corrosion facies are the best, chlorite cementation facies follows, which construct the favorable diagenetic facies of reservoir develop.

Key words: diagenesis, favorable diagenetic facies, Chang 8 reservoir, Heshui area, Ordos basin, petroleum gas