白云岩的成因、储集空间及实验技术研究新进展

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

李茜 胡安平 沈安江 张建勇 乔占峰 段军茂

Xi LI Anping HU Anjiang SHEN Jianyong ZHANG Zhanfeng QIAO Junmao DUAN

全球广布的白云岩中蕴含着丰富的油气资源，但是白云岩的成因机理和储集空间保持机制还存在诸多疑问。分析研究了近年来白云岩的成因机理、储集空间控制因素与新型实验技术等方面研究取得的重大进展。①通过溶解-再沉淀方法成功合成出低温有序白云石，白云岩的形成受热力学和动力学屏障共同制约。②研究建立、拓展和完善了多种白云石化模型。新建了有机物（微生物）诱导模型，完善了无机物催化模型，修订了混合水白云石化模型，拓展了蒸发泵和渗透回流白云石化模型，细化了埋藏白云石化类型。③原始沉积环境和后期成岩改造对白云岩储层演化具有重要控制作用。适度的白云石化作用及次生溶蚀作用增加白云岩储层的孔隙空间，过度的胶结作用、大量热液矿物沉淀及轻-中度重结晶作用减少白云岩储层的孔隙空间。④发展了微区元素分析、Mg-Ca同位素、激光原位U-Pb同位素、团簇同位素、激光共聚焦-CT扫描成像解析及核磁共振-频谱激发极化实验新技术。研发了白云岩储层正演模拟技术、多尺度定量表征白云岩孔隙的三维结构和流动性技术，为白云石成因机理、储集空间研究提供重要的技术支持。

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.

10.11743/ogg20240518