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This article reviews the applications of light stable isotope, including carbon, oxygen and hydrogen, in the studies on origin and formation temperature of authigenic carbonate, quartz and clay minerals. Theoretical knowledge and analytical methods for major light stable isotopes are introduced in detail. Negative and positive δ13C values indicate significant differences on the origin of carbonate cements. The δ18O value is an effective palaeotemperature scale for authigenic minerals formation. Various fractionation equations between δ18O and temperature are proposed for carbonate cements, quartz cements and clay minerals, whose merit and demerit, applicable conditions are clarified clearly. Clumped isotope analysis can reconstruct the temperature of carbonate precipitation with no requirement on the δ18O of initial waters, which makes temperature calculation of carbonate cements formation more convenient and accurate. Hydrogen and oxygen isotopes mainly reflect the origin of diagenetic fluid for clay mineral formation, providing reliable evidence for diagenetic environment analysis. This work aims at helping researchers for better understanding the applications of light stable isotope in sandstone diagenesis. [ABSTRACT FROM AUTHOR]

The Eocene sandstones in the northern Dongying Sag, Bohai Bay Basin, China, are reservoirs for large accumulations of hydrocarbons. The sandstones are mainly lithic arkoses and feldspathic litharenites, texturally and compositionally immature. These sandstones have a wide range of porosity (0.4–37%) and permeability (0.004–6969 mD) and show an overall decrease in reservoir quality from 1500 m to 5000 m below sea level. The reduction in reservoir quality is a product of several digenetic processes; these include compaction, precipitation of dolomite and calcite in eodiagenetic stage; compaction, feldspar dissolution, precipitation of quartz cements and clays (kaolin and illite) and precipitation of ferrocalcite and ankerite in mesodiagenetic stage. Mineral distribution pattern and isotopic composition suggest carbonate cements in sandstones originate from sources outside the sandstones. Carbonate cementation, together with compaction reduced the sandstones’ porosity and permeability significantly. In a sandstone bed, marginal sandstones with distance to sandstone/mudstone interface less than one meter always have lower porosity than central sandstones. As burial depth exceeds 4000 m, marginal sandstones have very low porosities (<5%), indicating that thin sandstone beds (<2 m) were totally destroyed by cementation and compaction, and only thick sandstone beds (>2 m) can be potential effective reservoirs. Feldspar dissolution and precipitation of clays and quartz cements have little impact on absolute porosity. Mineral distribution pattern and quantitative data show that leached feldspars are the internal source of authigenic quartz and clays in sandstones, and the volume difference between feldspar secondary porosity and related authigenic cements is generally less than 0.25%. However, although there is little or no net import of matter to the sandstones, the pore architecture changes dramatically. Primary macropores are lost as clays and quartz precipitate while the proportion of microporosity increases, occurring mainly between clay crystals. The overall result is that permeability is significantly degraded. [ABSTRACT FROM AUTHOR]