Abstract In this work, we apply digital rock physics (DRP) to characterize the pore networks of the Brae Formation sandstones from two different wells in the Miller field area (North Sea, UK). Using X-ray micro-CT scans, we calculate the porosity and permeability and generate pore network models to assess pore shape characteristics. The porous samples are marked by macroporosities ranging from 4.9 % to 15.2 % with the effective porosities varying from 0 to 14.8%. The samples also contained some microporosity hosted in secondary and accessory mineral phases, varying between 2.6% and 10.7%. Pore network model results for total porosity indicate that the samples have median pore and throat radii ranging from 5.5 μm to 16.8 μm and 6.4 μm–12.9 μm, respectively. The throat length of all samples has a median value ranging between 36.3 μm and 82.4 μm. The ratio between effective porosity and total porosity ( ϕ * ) varies with total porosity (ϕ) following the exponential relation ϕ * = 0.98 − e − ( ϕ − 0.032 ) / 0.028 . Pore network connectivity is established at a porosity of 3% and full communication is achieved at porosities exceeding 10%. Permeability was found to vary with total porosity with an exponent of 3.67. Based on these observations and the results from our models, the connectivity of the pore network has important implications for predicting reservoir performance during large scale subsurface projects such as hydrocarbon production and CO2 storage.

中文翻译：

---

北海Brae组砂岩孔隙网络分析

摘要 在这项工作中，我们应用数字岩石物理学 (DRP) 来表征来自 Miller 油田地区（英国北海）两口不同井的 Brae 组砂岩的孔隙网络。使用 X 射线显微 CT 扫描，我们计算孔隙度和渗透率并生成孔隙网络模型以评估孔隙形状特征。多孔样品的特点是大孔隙率范围为 4.9% 至 15.2%，有效孔隙率范围为 0 至 14.8%。样品还包含一些位于次生和副矿物相中的微孔，在 2.6% 和 10.7% 之间变化。总孔隙度的孔隙网络模型结果表明，样品的中值孔隙半径和喉道半径分别为 5.5 μm 至 16.8 μm 和 6.4 μm-12.9 μm。所有样品的喉长的中值介于 36.3 μm 和 82.4 μm 之间。有效孔隙度和总孔隙度 ( ϕ * ) 之间的比率随总孔隙度 (ϕ) 变化，遵循指数关系 ϕ * = 0.98 − e − ( ϕ − 0.032 ) / 0.028 。孔隙率在 3% 时建立孔隙网络连接，在孔隙率超过 10% 时实现完全通信。发现渗透率随总孔隙度变化，指数为 3.67。根据这些观察结果和我们模型的结果，孔隙网络的连通性对于预测大型地下项目（如碳氢化合物生产和 CO2 封存）中的储层性能具有重要意义。孔隙率在 3% 时建立孔隙网络连接，在孔隙率超过 10% 时实现完全通信。发现渗透率随总孔隙度变化，指数为 3.67。根据这些观察结果和我们模型的结果，孔隙网络的连通性对于预测大型地下项目（如碳氢化合物生产和 CO2 封存）中的储层性能具有重要意义。孔隙率在 3% 时建立孔隙网络连接，在孔隙率超过 10% 时实现完全通信。发现渗透率随总孔隙度变化，指数为 3.67。根据这些观察结果和我们模型的结果，孔隙网络的连通性对于预测大型地下项目（如碳氢化合物生产和 CO2 封存）中的储层性能具有重要意义。