| On the basis of a thorough review of the up-to-date relevant literatures, the characteristics, material sources,
and genetic mechanisms of carbonate cements in clastic reservoirs are systematically examined and discussed; the
distribution laws under different mechanisms are summarized; and several issues that should be paid attention to are
emphasized. Carbonate cements in clastic reservoirs are characterized by multiple mineral types, multiple formation
phases and heterogeneous distribution. The material sources of carbonate cements include both endogenous and
exogenous sources. Carbonate cements in clastic reservoirs can be formed by the synergistic diagenesis of sandstones and
mudstones, evaporation, bioclast dissolution and re-precipitation, sedimentation rate controlling effect, thermal
convection, deep hydrothermal fluid intrusion and other mechanisms. In the continental clastic reservoirs, the synergistic
diagenesis of sandstones and mudstones is one of the most important mechanisms for the formation of carbonate
cementation, but in marine-transitional strata, bioclastic dissolution and re-precipitation and sedimentation rate
controlling effect are also important mechanisms for the formation of carbonate cementation. The mineral types and
characteristics, controlling factors and distribution laws of carbonate cements under different mechanisms can vary
significantly. Given the current status in carbonate cementation in clastic reservoirs, it is emphasized that particular
attention needs to be paid to the uncertainty of the material sources proxied by δ13C value, the effect of high-frequency
sequence stratigraphy and sedimentary environments on carbonate cementation in the transitional depositional settings and
marine facies, and the non-unique interpretation of the origin of the same mineral type (such as “ankerite”) or the same
distribution (such as “top carbonate cementation layers”) when it comes to determine the genesis of carbonate cements. |
