The Emergent Impacts of Small Scale Capillary Heterogeneity on Field Scale CO2 Flow and Trapping
The Emergent Impacts of Small Scale Capillary Heterogeneity on Field Scale CO2 Flow and Trapping
复制标题
小规模毛细管异质性对现场规模二氧化碳流动和捕集的新兴影响
DOI：
10.1002/essoar.10500303.1
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Jackson S
中科院分区：
文献类型：
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作者：
Jackson S
我们采用实验和模拟相结合的多尺度方法来阐明小尺度(亚地震分辨率<；10m)毛管压力非均质性对野外尺度CO2流动和圈闭的影响。我们分析了英国北海金眼油田D船长砂岩100m范围内的48个岩芯(长约3 cm，直径约4 cm)。我们通过实验测量了岩心的孔隙度、毛管压力、绝对渗透率、相对渗透率和圈闭特征，这些参数被用来建立在毫米尺度上定义非均质性的三维数值模型。通过预测不同流量和气水流动分数下饱和度(毫米尺度)和压力测量(厘米尺度)的实验X射线CT观测，验证了这些模型的有效性。然后，将本征岩心尺度属性用于填充2D中尺度数值模拟(50m×10m大小)，并使用地质统计学表示法在厘米尺度上定义非均质性。通过改变实验观测范围内场的关联长度和方差，研究了不同毛细数、键数和重力数下小尺度非均匀对CO2羽流垂直和横向迁移的影响。在低流动潜力下，层状毛细压力非均质性可以加快羽流横向迁移高达20%，重力分离显著增强迁移(见图1)。在纵向上，层状非均质可以显著增加CO2的捕集作用，毛细管压力滞后的存在进一步增强了这种作用。最后，我们从考虑了小尺度非均质性影响的中尺度模拟中得到了毛细极限、提升尺度的等效性质。它们被用来表示金眼场(横向~5公里，深度200m)的全场3D数值模式中的网格块属性。我们分析了不同的相对渗透率(具有各向异性)对场尺度羽流迁移和捕获的影响。我们看到与使用固有岩石性质的情况相比有很大的差异，这表明在预测和评估现场规模的低流动潜力CO2羽流迁移的不确定性时，在向上扩展的工作流程中需要适当地包括小规模的非均质性。
We employ a multi scale approach combining experiments and modelling to elucidate the impacts of small scale (sub-seismic resolution <10m) capillary pressure heterogeneities in field scale CO2 flow and trapping. We analyse 48 rock cores (~3cm length, 4cm diameter) covering the entire 100m interval of the Captain D sandstone in the Goldeneye field, UK North Sea. We experimentally measure porosity, capillary pressure, absolute permeability, relative permeability and trapping characteristics for the cores, which are used to create 3D numerical models with heterogeneities defined at the mm scale. These models are validated by predicting experimental X-Ray CT observations of saturation (mm scale) and pressure measurements (cm scale) at various flow rates and fractional flows of gas-water. The intrinsic, core scale properties are then used to populate 2D meso scale numerical simulations (50m x 10m size), with heterogeneities defined at cm scale using a geostatistical representation. We vary the correlation length and variance of the fields within the bounds of the experimental observations to investigate the impacts of small scale heterogeneity on vertical and lateral CO2 plume migration under different Capillary, Bond and Gravity numbers. At low flow potential, layered capillary pressure heterogeneities can speed up lateral plume migration by up to 20%, with gravitational segregation significantly enhancing the migration (See Fig. 1). In the vertical case, layered heterogeneities can significantly increase CO2 trapping, which is further enhanced with the inclusion of capillary pressure hysteresis. Finally, we derive capillary limit, upscaled equivalent properties from the meso scale simulations, which incorporate the impacts of small scale heterogeneity. These are used to represent the grid block properties in a full field 3D numerical model of the Goldeneye field (lateral ~5 km, depth 200m). We analyse the impact of varying relative permeabilities (with anisotropy) on the field scale plume migration and trapping. We see large differences compared to cases using intrinsic rock properties, indicating that proper inclusion of small scale heterogeneity is needed in upscaling workflows when predicting and assessing uncertainty in low flow potential CO2 plume migration at the field scale.