THE INFLUENCE OF DIAGENESIS ON RESERVOIR QUALITY IN SHIHEZI-SHANXI FORMATION IN NORTHERN ORDOS BASIN
HU Jiang nai, ZHANG Shao nan, LI De min (Chengdu University of Technology, China)
Diagenesis influences the reservoir quality. The diagenetic pathways in sandstones are complex, being governed by numerous interrelated parameters, such as, mineral composition, deposition faces, as well as the composition and flow patterns of basinal fluids. The diagenetic processes that govern reservoir properties include the extent of compaction, cementation (mainly by carbonates, quartz, and clay minerals), and dissolution of framework grains. With increasing burial depth, sandstones progressively lose porosity. In deep sandstones, porosity is decreased mainly due to carbonate and quartz cementation, but, at the same time, cements also protect grains from further compaction. The aim of this study is to unravel the influence of diagenesis on the reservoir quality by analyzing the relationship between porosity, permeability and the content of corbonate cement , quartz cement and authigenetic clay minerals, respectively.