Strengthening of Calcite Assemblages Through Chemical Complexation Reactions
Strengthening of Calcite Assemblages Through Chemical Complexation Reactions
复制标题
通过化学络合反应强化方解石组合
DOI：
10.1029/2021gl094316
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发表时间：
2021
影响因子：
5.2
通讯作者：
A. Ilgen
中科院分区：
文献类型：
--
作者：
R. Choens;J. Wilson;A. Ilgen
地下储集层的利用，包括流体的抽取/注入，可以引起应力变化，改变导致亚临界压裂和变形的就地化学平衡。在这里，我们表明，在颗粒方解石组合固结过程中，裂尖内新形成的断裂面上的化学络合反应限制了断裂。此前，我们已经证明了类似的化学络合反应可以提高预裂单晶方解石的原位断裂韧性。为了测试地下条件下的化学络合效应，我们在增加静水压力的情况下固化样品，以在含有常见阴离子的流体存在下诱导广泛的晶间破裂。测量的固结、声发射和显微破裂表明，变形与方解石和水中阴离子对钙的络合亲和力有关。我们观察到，在提供足够的阴离子扩散速率的情况下，当存在强络合阴离子(如硫酸盐)时，变形最小。这一认识对于预测复杂含水流体条件下的储层有效强度具有重要意义。
Utilization of subsurface reservoirs, including fluid extraction/injection, can induce stress changes and modify in‐situ chemical equilibrium causing subcritical fracturing and deformation. Here, we show that chemical complexation reactions at the newly created fracture surfaces within the crack tip limit fracturing during consolidation of granular calcite assemblages. Previously, we showed that analogous chemical complexation reactions can increase in‐situ fracture toughness in pre‐fractured single crystal calcite. To test the chemical complexation effect under subsurface conditions, we consolidated samples under increasing hydrostatic pressure to induce widespread intergranular fracturing in the presence of fluid containing common anions. Measured consolidation, acoustic emissions, and microfracturing demonstrate that deformation correlates with complexation affinity for calcium in calcite and aqueous anions. We observed that deformation is lowest in the presence of strongly complexing anions (e.g., sulphate), provided sufficient anion diffusion rates. This understanding is important for predicting reservoir effective strength in the presence of complex aqueous fluids.