Modeling brine leakage to shallow aquifer through an open wellbore using T2WELL/ECO2N
Modeling brine leakage to shallow aquifer through an open wellbore using T2WELL/ECO2N
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使用 T2WELL/ECO2N 对通过开放井眼向浅层含水层渗漏的盐水进行建模
DOI：
10.1016/j.ijggc.2012.05.010
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发表时间：
2012-07
影响因子：
3.9
通讯作者：
Keni Zhang
中科院分区：
文献类型：
--
作者：
Litang Hu;Lehua Pan;Keni Zhang
深层盐水地层中二氧化碳封存的效率和可持续性取决于上覆盖层的完整性。现有的石油和天然气井穿透地层，是潜在的泄漏通道。在本文中，T2WELL/ECO2N（一种二氧化碳和盐水的耦合井筒-储层流动模拟器）用于分析盐度和超孔隙压力（EPP）对盐水从注入储层渗漏到浅层新鲜含水层的影响。还评估了等效多孔介质 (EPM) 方法的有效性，该方法是井眼-储层模拟中广泛使用的井眼流动近似方法。建立假设模型，创建低、中、高盐度下 EPP 0.1MPa、0.5MPa 和 1.5MPa 的测试用例。结果表明，如果CO2注入引起的EPP高于阈值EPP，将很快建立准稳态泄漏率。然而，盐水盐度对盐水泄漏率有重要影响，包括阈值 EPP，低于该阈值则不发生泄漏。泄漏率随着盐度的增加而减小，而阈值EPP随着盐度的增加而增加。对于相同的盐水盐度，准稳态泄漏率随 EPP 非线性增加。 EPM方法计算的泄漏率对井筒的等效渗透率非常敏感，然而，这并不是给定井筒-含水层系统的固有参数。虽然 EPM 方法可以通过拟合渗透率相当好地再现动态泄漏率，但对于同一系统，它可能会高估或低估泄漏率几个数量级，具体取决于由于废弃井的盐度和/或 EPP 的变化而导致的真实泄漏率本身是否小于或大于拟合情况。等效渗透率对流量的依赖性使得 EPM 方法不是预测井眼泄漏的可行方法，除非泄漏率非常小的情况。
The efficiency and sustainability of CO2storage in deep saline formations depends on the integrity of the overlying caprocks. Existing oil and gas wells, which penetrate the formations, are potential leakage pathways. In this paper, T2WELL/ECO2N, a coupled wellbore–reservoir flow simulator of carbon dioxide and brine, is employed to analyze the effects of salinity and excess pore pressure (EPP) on brine leakage from an injection reservoir to a shallow fresh aquifer. The effectiveness of the Equivalent Porous Media (EPM) approach, a widely used approximation of wellbore flow in wellbore–reservoir simulations, is also evaluated. A hypothetical model is built to create test cases with EPP of 0.1MPa, 0.5MPa and 1.5MPa under low-, middle-, and high-salinity. The results show that a quasi-steady-state leakage rate will be quickly established if the EPP caused by CO2injection is higher than the threshold EPP. However, the brine salinity has an important impact on the brine leakage rate including the threshold EPP below which no leakage occurs. The leakage rate decreases with the increase of the salinity whereas the threshold EPP increases with the increase of the salinity. For the same brine salinity, the quasi-steady-state leakage rate increases with the EPP nonlinearly. The leakage rate calculated by the EPM approach is very sensitive to the equivalent permeability of the wellbore, which however, is not an intrinsic parameter of a given wellbore–aquifer system. Although the EPM approach could reproduce the dynamic leakage rate reasonably well with a fitted permeability, it could over- or underestimates the leakage rate by orders in magnitude for the same system depending on whether the true leakage rate itself is smaller or larger than that of the fitting case due to changes in the salinity and/or the EPP through an abandoned well. The dependence of the equivalent permeability on the flow rate makes the EPM approach not to be a viable method for predicting wellbore leakage except for the cases with very small leakage rates.
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影响因子：
4.7
作者：
L. Pan;S. Webb;C. Oldenburg
通讯作者：
L. Pan;S. Webb;C. Oldenburg
DOI：
10.1007/s00254-004-1073-5
发表时间：
2004-10-01
期刊：
ENVIRONMENTAL GEOLOGY
影响因子：
--
作者：
Gasda, SE;Bachu, S;Celia, MA
通讯作者：
Celia, MA
影响因子：
2.2
作者：
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通讯作者：
L. Pan;C. Oldenburg;K. Pruess;Yushu Wu
影响因子：
3.9
作者：
J. Nicot
通讯作者：
J. Nicot
影响因子：
2.7
作者：
A. Battistelli;P. Ceragioli;M. Marcolini
通讯作者：
A. Battistelli;P. Ceragioli;M. Marcolini