Saline Brine Reaction with Fractured Wellbore Cement and Changes in Hardness and Hydraulic Properties
Saline Brine Reaction with Fractured Wellbore Cement and Changes in Hardness and Hydraulic Properties
复制标题
盐水与压裂井眼水泥的反应以及硬度和水力性能的变化
DOI：
10.1089/ees.2020.0093
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发表时间：
2021
影响因子：
1.8
通讯作者：
Cerrato, José M.
中科院分区：
文献类型：
--
作者：
Gonzalez-Estrella, Jorge;Ellison, Joshua;Stormont, John C.;Shaikh, Nabil;Peterson, Eric J.;Lichtner, Peter;Cerrato, José M.
固井井眼的完整性是控制地下温室气体和碳氢化合物的基础，同时最大限度地减少深层地下卤水的迁移。这些盐水含有盐类和危险化学物质，可能会污染饮用水资源。本研究结合流动测量、X射线衍射仪、显微镜和溶液化学，研究了在不同应力条件下，在中性条件下盐水与压裂井眼水泥反应的物理化学效应。盐水与水泥裂缝表面的化学反应会改变裂缝的渗透率和孔隙度，从而影响井筒渗漏的可能性。在受控的实验室条件下，用氮气、去离子水和盐水对破裂的井筒水泥试件进行了一系列静水围压应力的流动测量。通过氮气流量测量获得的水力孔径随着施加到裂缝上的围压的初始增加而减小，这是由于破碎的粗糙物造成的。在盐水流动过程中，与未反应状态相比，水力孔径逐渐减小四倍。沿流动路径沉淀的方解石可能会减小水力孔径，限制流体通过受损井筒系统的输送。我们的结果表明，相对于CaCO_3过饱和的盐水(S)促进了井筒表面的沉淀，表现为裂缝孔径最初迅速下降，然后随着孔隙体积的增加，孔径逐渐减小。这一结果表明，注入卤水可能会减少碳氢化合物流体向环境中的泄漏。
The integrity of cemented wellbores is fundamental to the containment of subsurface greenhouse gases and hydrocarbons, while minimizing migration of deep subsurface brines. These brines contain salts and hazardous chemicals that could contaminate potable water resources. This study integrated flow measurements, X-ray diffraction, microscopy, and solution chemistry to investigate the physicochemical effects of reacting saline brine waters at circumneutral pH with fractured wellbore cement under varying stress conditions. Chemical reactions of saline brines with cement fracture surfaces can alter the permeability and porosity of the fracture and consequently impact the potential for leakage through the wellbore. Flow measurements on fractured wellbore cement specimens were made with nitrogen, de-ionized water, and finally brine for a range of hydrostatic confining stresses under controlled laboratory conditions. Hydraulic apertures obtained from nitrogen flow measurements decreased in response to the initial increase in confining stress applied to the fracture owing to crushing of asperities. During flow of saline brine, the hydraulic aperture progressively decreased fourfold compared with its unreacted condition. Precipitation of calcite along the flow path likely decreased the hydraulic aperture, limiting the fluid transport through the damaged wellbore system. Our results indicate that saline brine supersaturated with respect to CaCO3(s)promotes precipitation at the wellbore surface showing an initial rapid drop in the fracture aperture followed by a more gradual reduction in the aperture with increasing pore volume. This result suggests injection of brine may reduce leakages of hydrocarbon fluids into the environment.