The adsorption interaction of oil field tracer in drilling fluid plays a significant role in tracer monitoring (TM) technology in the petroleum industry. In this work, the adsorption performances of Rhodamine B (RhB⁺) and fluorescein sodium (Fln^–) tracers with montmorillonite (MMT) crystal in drilling fluid were investigated by both experimental and simulation methods. For the experimental aspect, the macroscopic results indicate thermodynamic monolayer adsorption by the Langmuir model and kinetic chemical adsorption by the pseudo-second-order (PSO) model. As a result, MMT shows a larger adsorption capacity (q_m) for RhB⁺ than for Fln^– with qm(RhB+)=0.069gg−1>qm(Fln−)=0.016gg−1$q_{\mathrm{m}({\mathrm{RhB}}^{+})}=0.069\mathrm{g}{\mathrm{g}}^{-1}>q_{\mathrm{m}({\mathrm{Fln}}^{-})}=0.016\mathrm{g}{\mathrm{g}}^{-1}$$q_{\mathrm{m}({\mathrm{RhB}}^{+})}=0.069\mathrm{g}{\mathrm{g}}^{-1}>q_{\mathrm{m}({\mathrm{Fln}}^{-})}=0.016\mathrm{g}{\mathrm{g}}^{-1}$ but stronger adsorption spontaneity (Δ_rG_m^θ) for Fln^– than for RhB⁺ with ΔrGθm(Fln−)=−7.92${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{Fln}}^{-})}=-7.92$${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{Fln}}^{-})}=-7.92$ kJ mol^–1 < ΔrGθm(RhB+)=−6.90${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{RhB}}^{+})}=-6.90$${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{RhB}}^{+})}=-6.90$ kJ mol^–1. Meanwhile, the interaction rate (k₂) of Fln^– was shown to be faster than that of RhB⁺ with k2(Fln−)=1.07min−1>k2(RhB+)=0.95min−1${k_2}_{({\mathrm{Fln}}^{-})}=1.07{\min }^{-1}>{k_2}_{({\mathrm{RhB}}^{+})}=0.95{\min }^{-1}$${k_2}_{({\mathrm{Fln}}^{-})}=1.07{\min }^{-1}>{k_2}_{({\mathrm{RhB}}^{+})}=0.95{\min }^{-1}$. For simulation insight, MMT shows much higher system stability (E) for Fln^– than for RhB⁺ with EFln−⋅⋅⋅MMT<ERhB+⋅⋅⋅MMT$E_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}<E_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$$E_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}<E_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$ and ΔEFln−⋅⋅⋅MMT>ΔERhB+⋅⋅⋅MMT$\mathrm{\Delta }{E}_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}>\mathrm{\Delta }{E}_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$$\mathrm{\Delta }{E}_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}>\mathrm{\Delta }{E}_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$. Meanwhile, the microscopic simulation results reveal configuration changes and site distinctions for RhB⁺ and Fln^– interactions with the MMT crystal. The different adsorption responses were explained by proposing an interaction mechanism of force dominance and position orientation. Specifically, Fln^– was deduced to interact with metal (Al, Ca) and metalloid (Si) elements in the MMT crystal interlayer by “upright-insertion” orientation while RhB⁺ was deduced to interact with oxygen atoms on the MMT crystal surface by a “flat-lying” orientation. Hydrogen bonds, the electrostatic interaction, and the coordination effect were revealed to dominate for the interaction of tracer adsorption. This work provides both performance and mechanism investigation of fluorescent tracer adsorption interaction with the MMT crystal in drilling fluid, which is of great significance in reservoir exploitation.

中文翻译：

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荧光示踪剂与蒙脱石晶体在钻井液中吸附相互作用的实验与模拟研究


油田示踪剂在钻井液中的吸附作用在石油工业的示踪剂监测 （TM） 技术中起着重要作用。本工作通过实验和模拟方法研究了罗丹明 B （RhB⁺） 和荧光素钠 （Fln^–） 示踪剂与蒙脱石 （MMT） 晶体在钻井液中的吸附性能。在实验方面，宏观结果表明 Langmuir 模型存在热力学单分子层吸附，伪二级 （PSO） 模型存在动力学化学吸附。因此，MMT 显示 RhB⁺ 的吸附容量 （q_m） 大于 Fln^–q
m（RhB+）
=0.069克g−1>q
米（Fln−）
=0.016克g−1$q_{\mathrm{m}({\mathrm{RhB}}^{+})}=0.069\mathrm{g}{\mathrm{g}}^{-1}>q_{\mathrm{m}({\mathrm{Fln}}^{-})}=0.016\mathrm{g}{\mathrm{g}}^{-1}$$q_{\mathrm{m}({\mathrm{RhB}}^{+})}=0.069\mathrm{g}{\mathrm{g}}^{-1}>q_{\mathrm{m}({\mathrm{Fln}}^{-})}=0.016\mathrm{g}{\mathrm{g}}^{-1}$
但 Fln– 的吸附自发性 （Δ_rG_m^θ） 强^于 RhB⁺ΔrGθm(Fln−)=−7.92${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{Fln}}^{-})}=-7.92$${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{Fln}}^{-})}=-7.92$ 千焦摩尔^–1 <ΔrGθm(RhB+)=−6.90${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{RhB}}^{+})}=-6.90$${\mathrm{\Delta }}_{\mathrm{r}}{G_{\mathrm{m}}^{\theta }}_{({\mathrm{RhB}}^{+})}=-6.90$
千焦摩尔^–1.同时，Fln 的相互作用速率 （k₂） ^– 显示比 RhB⁺ 更快，其中k2(Fln−)=1.07 分钟−1>k2(RhB+)=0.95 分钟−1${k_2}_{({\mathrm{Fln}}^{-})}=1.07{\min }^{-1}>{k_2}_{({\mathrm{RhB}}^{+})}=0.95{\min }^{-1}$${k_2}_{({\mathrm{Fln}}^{-})}=1.07{\min }^{-1}>{k_2}_{({\mathrm{RhB}}^{+})}=0.95{\min }^{-1}$
.对于仿真洞察，MMT 显示 Fln^– 的系统稳定性 （E） 远高于 RhB⁺，其中EFln−⋅⋅⋅MMT<ERhB+⋅⋅⋅MMT$E_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}<E_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$$E_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}<E_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$ 和ΔEFln−⋅⋅⋅MMT>ΔERhB+⋅⋅⋅MMT$\mathrm{\Delta }{E}_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}>\mathrm{\Delta }{E}_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$$\mathrm{\Delta }{E}_{{\mathrm{Fln}}^{-}···\mathrm{MMT}}>\mathrm{\Delta }{E}_{{\mathrm{RhB}}^{+}···\mathrm{MMT}}$
.同时，微观模拟结果揭示了 RhB⁺ 和 Fln^– 与 MMT 晶体相互作用的构型变化和位点差异。通过提出力支配和位置方向的交互机制来解释不同的吸附响应。具体来说，Fln^– 被推导出为通过“直立插入”方向与 MMT 晶体夹层中的金属（Al、Ca）和准金属 （Si） 元素相互作用，而 RhB⁺ 被推断为通过“平躺”方向与 MMT 晶体表面的氧原子相互作用。氢键、静电相互作用和配位效应在示踪剂吸附的相互作用中占主导地位。本工作为荧光示踪剂吸附与钻井液中MMT晶体相互作用的性能和机理研究提供了研究，在油藏开发中具有重要意义。