Experimental techniques for carbonate reservoirs: Review, progress, and prospects

A systematic review and summary of the developmental history and advances in experimental techniques for carbonate reservoirs reveals that technological progress in experimentation serves as a fundamental driving force behind theoretical and technological innovations in the field. The research results are as follows. (1) The evolution from macro-scale reservoir characterization via visual inspection and magnifying lenses in the 1950s and 1960s to modern digital outcrop acquisition, 3D micro-to-nano pore imaging, and multi-scale reservoir heterogeneity characterization and modeling in the 21st century, underscores the pivotal role of theoretical and experimental technological advancements, particularly in carbonate petrology, sedimentology, sequence stratigraphy, and the deployment of sophisticated experimental equipment. (2) “Geochronology, thermometry, barometry, and fluid property tracing” represent the most cutting-edge geochemical testing techniques for carbonate reservoirs in the 21st century. The iterative upgrading from bulk-rock to in-situ micro-area analysis, from solution-based methods to laser ablation, and from point detection to area mapping defines the future trajectory of the field. Furthermore, digital transformation and intelligent development provide the impetus for these technical upgrades, which will yield more comprehensive and reliable data for investigating the genesis of diagenetic fabrics and diagenetic-porosity evolution. (3) The high-temperature and high-pressure (HTHP) visualization apparatus for reservoir formation simulation across tectonic stages in ultra-deep layers is the core equipment for investigating the genetic mechanisms of ultra-deep reservoirs. It can accurately replicate ultra-HTHP geological environments, enabling dynamic forward modeling of water-rock interaction processes across tectonic stages, and integrates in-situ real-time monitoring of fluid properties and rock permeability. This apparatus provides direct experimental evidence for unraveling the formation mechanisms, preservation conditions, and spatial distribution patterns of secondary porosity in ultra-deep carbonate reservoirs. The elucidation of hydrocarbon accumulation mechanisms in ultra-deep carbonate reservoirs via simulation experiments represents a defining future research trend. (4) Reservoir prediction is the ultimate objective of reservoir characterization, evaluation, genesis, and modeling. Given that geophysical techniques are the primary tools for reservoir identification and prediction, it is highly recommended to strengthen the organic integration of experimental carbonate reservoir techniques with geophysical methods.