Esteves Barbara F, Spielman-Sun Eleanor, Li Qingyun, Jew Adam D, Bargar John R, Druhan Jennifer L
Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.
Environ Sci Technol. 2022 Apr 5;56(7):4336-4344. doi: 10.1021/acs.est.1c07717. Epub 2022 Mar 17.
Celestite (SrSO) precipitation is a prevalent example of secondary sulfate mineral scaling issues in hydraulic fracturing systems, particularly in basins where large concentrations of naturally occurring strontium are present. Here, we present a validated and flexible geochemical model capable of predicting celestite formation under such unconventional environments. Simulations were built using CrunchFlow and guided by experimental data derived from batch reactors. These data allowed the constraint of key kinetic and thermodynamic parameters for celestite precipitation under relevant synthetic hydraulic fracturing fluid conditions. Effects of ionic strength, saturation index, and the presence of additives were considered in the combined experimental and modeling construction. This geochemical model was then expanded into a more complex system where interactions between hydraulic fracturing fluids and shale rocks were allowed to occur subject to diffusive transport. We find that the carbonate content of a given shale and the presence of persulfate breaker in the system strongly impact the location and extent of celestite formation. The results of this study provide a novel multicomponent reactive transport model that may be used to guide future experimental design in the pursuit of celestite and other sulfate mineral scale mitigation under extreme conditions typical of hydraulic fracturing in shale formations.
天青石（SrSO₄）沉淀是水力压裂系统中次生硫酸盐矿物结垢问题的一个普遍例子，特别是在天然锶含量高的盆地中。在此，我们提出了一个经过验证的灵活地球化学模型，能够预测在这种非常规环境下天青石的形成。模拟是使用CrunchFlow构建的，并以来自间歇式反应器的实验数据为指导。这些数据确定了在相关合成水力压裂液条件下天青石沉淀的关键动力学和热力学参数。在综合实验和模型构建中考虑了离子强度、饱和指数和添加剂的存在的影响。然后，这个地球化学模型被扩展到一个更复杂的系统中，在这个系统中，水力压裂液和页岩之间的相互作用在扩散传输的条件下发生。我们发现，给定页岩的碳酸盐含量和系统中过硫酸盐破胶剂的存在强烈影响天青石形成的位置和程度。这项研究的结果提供了一个新的多组分反应传输模型，可用于指导未来的实验设计，以在页岩地层水力压裂典型的极端条件下减轻天青石和其他硫酸盐矿物结垢。
