储层孔隙系统“水—岩”反应结晶动力学研究进展

Study of the Crystallization Kinetics for“Water-Rock”Interactions in the Reservoir Pore-System:An overview

“水—岩”反应作为储层成岩作用研究的重要组成部分,其研究结果对解释储层非均质性成因机制、综合评价储层品质等方面都具有重要意义。近年来随着基础理论、分析测试手段、物理实验方法和模拟技术的进步,该领域研究取得了诸多进展。成岩物理模拟实验的进步实现了对流体—围岩/矿物体系“水—岩”作用过程的宏观尺度观测和研究,也明确了各物理化学参数对体系内矿物溶解—结晶过程的影响,但分辨率限制了其在微观(纳米)尺度解释许多现象成因机制和约束条件方面的应用。晶体生长理论的建立和发展为解释储层孔隙系统中“水—岩”作用过程的结晶动力学原理奠定了基础,特别是近年来伴随纳米科技而发展起来的各种在线和非在线测量技术大大提高了储层孔隙系统结构和内部晶体生长情况的观测精度,将“水—岩”作用研究分辨率提升至纳米级,这为从微观尺度了解孔隙系统中流体—矿物体系的溶解—结晶(沉淀)相平衡过程及其控制因素提供了方案。储层孔隙系统中流体的结晶动力学行为与孔隙介质和流体性质密切相关,是成核自由能、矿物表面电化学特征、传质速率等多因素综合作用的结果。对不同成岩环境和孔隙系统中孔隙流体结晶动力学行为的系统研究,有助于了解孔隙系统空间结构、底衬表面化学特性、表面能效应等对矿物晶体成核生长与溶解过程的影响,为进一步深入解释储层非均质性的结晶动力学原理奠定了理论基础。

The“water-rock”interaction is an important part of the study of reservoir diagenesis,and its research re⁃sults are of great significance in explaining the genetic mechanism of reservoir heterogeneity and the comprehensive evaluation of reservoir quality.In recent years,with the progress of basic theory,analytical testing methods,physical experiment methods,and simulation technology,much progress has been made in this field.For example,the im⁃provement of physical modeling experiments of diagenesis has realized the macroscopic observation and research of the“water-rock”interaction process of the fluid-host rock/mineral system and clarified the influence of various physi⁃cochemical parameters on the mineral dissolution-crystallization process that take place in the system.However,the low resolution of physical modeling experiments on diagenesis limits its application in explaining the genetic mecha⁃nism and constraints of many phenomena on the micro(nano)scale.The establishment and development of crystal growth theory has laid a foundation for explaining the crystallization kinetics of the“water-rock”interaction process in the reservoir pore system.In particular,various on-line and off-line measurement techniques developed with nano⁃technology in recent years have greatly improved the observation accuracy of the reservoir pore system structure and internal crystal growth,enhancing the resolution of“water-rock interaction”research to the nanometer level.This im⁃provement provides a basis for understanding the dissolution crystallization(precipitation)phase equilibrium process and its mechanism of the fluid mineral system in pore system from the microscopic scale.The crystallization kinetics of fluid in the reservoir pore system is closely related to the pore medium system and fluid properties,which is the re⁃sult of the comprehensive action of nucleation free energy,surface electrochemical characteristics of the mineral,mass transfer rate,and other factors.A systematic study on pore fluid crystallization kinetics in different diagenetic environments and pore systems is helpful in understanding the effects of the pore system spatial structure,surface chemical properties of the substrate,and surface energy on the nucleation and growth process of mineral crystals,lay⁃ing a theoretical foundation for further understanding the crystallization kinetics principle of reservoir heterogeneity.