Recent advances in the study of the origin and reservoir space of dolomites and emerging experimental techniques

Dolomites, distributed extensively across the world, are known to contain abundant hydrocarbon resources. However, questions regarding their formation mechanisms and reservoir space preservation are yet to be clarified. We delve into recent significant advances in the study of dolomites’ genetic mechanisms and factors governing their reservoir space, along with emerging experimental techniques. The findings indicate that low-temperature ordered dolomites can be successfully synthesized through dissolution-reprecipitation reactions and that dolomite formation is constrained by both thermodynamic and kinetic barriers. Various dolomitization models have been established, expanded, and improved, including the newly constructed organic matter- or microbially induced dolomitization model, the enhanced inorganically catalyzed dolomitization model, and the modified mixed-water-zone dolomitization model. Furthermore, the model for dolomitization by evaporative pumping and seepage reflux of brines has been expanded, and the burial dolomitization model has been refined. The findings highlight the significant controlling effects of the original sedimentary environment and late-stage diagenetic transformations on the evolution of dolomite reservoirs. Moderate dolomitization and secondary dissolution increase the porosity of dolomite reservoirs. In contrast, excess cementation, precipitation of substantial hydrothermal minerals, and mild to moderate recrystallization lead to a decrease in reservoir porosity. Novel experimental techniques have been developed, including element microanalysis, Mg-Ca isotopic tracing, in-situ U-Pb isotopic dating by laser ablation inductively coupled plasma mass spectrometry (LA-ICP/MS), clumped isotope thermometry, confocal laser scanning microscopy (CLSM) combined with CT scanning imaging, and nuclear magnetic resonance (NMR) combined with spectral induced polarization (SIP). Additionally, techniques for the forward modeling of dolomite reservoirs and the multiscale quantitative characterization of the 3D structures and fluid mobility of dolomite pores have also been developed. These emerging techniques provide significant technical support for research on the genetic mechanisms and reservoir space of dolomites.