页岩自封闭研究进展及发展趋势OA

With the continuous advancement of global unconventional oil and gas exploration and development,shale self-sealing has become a core scientific topic to unravel the mechanisms governing in-situ retention,enrichment and preservation of hydrocarbons within shale reservoirs.It bears significant theoretical value and practical exploration significance for evaluating favorable zones and predicting sweet-spot intervals of shale oil and gas.Based on a systematic review of the research history and global advances in shale self-sealing,this paper elaborates its formation principles,microscopic mechanisms,primary controlling factors,and multi-scale charac-terization methods,and further dissects the macroscopic geological constraints governing the development of self-sealing.As indicated by the research results,shale self-sealing essentially arises from the combined intermolecular forces among hydrocarbon molecules and the interfacial molecular interactions between hydrocarbons and reservoir media inside the pore-fracture networks of shale.Three synergistic microscopic mechanisms,namely connectivity-dominated self-sealing,capillary force-governed self-sealing,and adsorption-driven force self-sealing,jointly regulate hydrocarbon retention and enrichment.The effectiveness of shale self-sealing is co-controlled by micro-scopic and macroscopic factors.Microscopic factors include pore architecture,mineral assemblage,fracture intensity,medium interfacial properties,water saturation,and organic matter attributes,while macroscopic fac-tors encompass formation temperature-pressure conditions,rock mechanical properties,tectonic activities,and sedimentary-diagenetic evolutionary processes.This study establishes a multi-scale quantitative characterization framework tailored to the three self-sealing mechanisms on the basis of an integrated suite of laboratory tests and numerical simulation techniques,including low-temperature gas adsorption,nuclear magnetic resonance(NMR),sequential solvent extraction,high-pressure mercury intrusion,microscopic imaging,core flooding experiments,and molecular dynamics simulations.The generation and evolution of the shale self-sealing system stem from the coupling between microscopic mechanisms and macroscopic geological conditions.Macroscopic fac-tors govern the spatial-temporal distribution and intensity evolution of the self-sealing system by regulating key parameters such as pore architecture,interfacial characteristics,and adsorption capacity.Meanwhile,the three microscopic self-sealing mechanisms mutually couple and produce synergistic enhancement,collectively domina-ting the enrichment and preservation of shale oil and gas.At present,several critical bottlenecks restrict the research on shale self-sealing:ambiguous cognition of self-sealing mechanisms in deep and ultra-deep shale sequences,a lack of quantitative models for multi-factor coupling,imperfect evaluation workflows for dynamic evolutionary processes,insufficient systematic research on differential self-sealing mechanisms across varied deposi-tional settings,and underdeveloped cross-scale coupling technologies linking micro and macro geological responses.Future research on shale self-sealing will advance toward in-situ monitoring,dynamic simulation,quantitative characterization,and cross-scale correlation analysis.Breakthroughs in key technologies are urgently required,including in-situ characterization,dynamic evolution modeling,multi-factor coupled prediction,and cross-scale quantitative correlation modeling between microscopic and macroscopic geological features.