Shallow-marine reservoirs of the Upper Cretaceous Cardium Formation contain one of the largest light oil accumulations in Canada, which have been exploited since the 1950s. Since 2008, multistage fractured horizontal wells have revived this play. This study presents a reservoir characterization of the offshore to shoreface unconventional reservoirs of the Cardium Formation in the halo play along the western margin of the legacy Pembina oil pool in central Alberta. Although permeability of these facies is too low to achieve economic production from vertical wells, they were the main carrier beds forming the migration pathway for charging the updip conventional reservoirs in the Pembina field.Three reservoir facies are present in the west Pembina study area: bioturbated muddy sandstones, interbedded sandstones and mudstones, and hummocky cross-stratified sandstones. Shoreface sandstones are relatively thin in the halo play area; thus, significant production in the horizontal wells is attributed to the thin sandstone beds and bioturbated muddy sandstone reservoir facies.To characterize these unconventional, heterogenous reservoirs, traditional reservoir evaluation techniques are integrated with computerized tomography scanning to better evaluate reservoir properties and flow pathways. Cutoffs of 90 gamma-ray API units, 6% porosity, and 0.075-md permeability were used to create a series of reservoir property maps. These detailed maps show the most prospective area of the halo play is a 4-km (2.5-mi)-wide zone immediately to the west of the legacy west Pembina Pool boundary. This lateral heterogeneity with narrow sweet spot fairways explains the significant production variability in these shallow-marine reservoirs.

中文翻译：

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加拿大艾伯塔省西 Pembina 上白垩统 Cardium 组致密轻质油区球道储层特征

上白垩统 Cardium 组的浅海油藏包含加拿大最大的轻质油藏之一，自 1950 年代以来一直被开采。自 2008 年以来，多级压裂水平井重新启动了这一工作。本研究展示了沿阿尔伯塔省中部遗留的 Pembina 油池西缘晕圈区 Cardium 组的近海到岸面非常规储层的储层特征。虽然这些相的渗透率太低，无法实现垂直井的经济生产，但它们是形成彭比纳油田上倾常规储层的运移通道的主要载体床。 西彭比纳研究区存在三种储层相：生物扰动泥质砂岩、互层砂岩和泥岩，和丘状交叉层状砂岩。晕游区的岸面砂岩相对较薄；因此，水平井的显着产量归因于薄砂岩层和生物扰动的泥质砂岩储层相。为了表征这些非常规非均质储层，将传统储层评价技术与计算机断层扫描相结合，以更好地评价储层性质和流动路径。使用 90 个伽马射线 API 单位、6% 孔隙度和 0.075-md 渗透率的临界值来创建一系列储层特性图。这些详细的地图显示，晕圈最有前景的区域是紧邻传统西 Pembina Pool 边界以西的 4 公里（2.5 英里）宽区域。