Fracture attribute scaling and connectivity in the Devonian Orcadian Basin with implications for geologically equivalent sub-surface fractured reservoirs [dataset]

Fracture attribute scaling and connectivity datasets from analogue systems are widely used to inform sub-surface fractured reservoir models in a range of geological settings. However, significant uncertainties are associated with the determination of reliable scaling parameters in surface exposures, particularly for fault widths and fracture aperture. This has limited our ability to upscale key parameters that control fluid-flow at reservoir to basin scales. In this study, we present nine 1D‑transect (scanline) fault and fracture attribute datasets from Middle Devonian sandstones in Caithness (Scotland) that are widely used as an onshore analogue for nearby sub-surface reservoirs such as the Clair Field, West of Shetland. Our multiscale analysis confirms power-law behaviours for both length over 8 orders of magnitude (10-4 to 104) and fracture aperture and fault width (including fills) over 4 orders of magnitude (10-6 to 10-2). We also present a 2D fault and fracture topology analysis which allows assessment of the heterogeneity of connectivity and self‑similarity. This multiscale approach provides a new basis for upscaling micro- to meso-scale fracture attributes collected in outcrop analogues for use in static and dynamic reservoir models at reservoir to basin scales.

来自类比系统的裂缝属性尺度化与连通性数据集，已被广泛用于指导多种地质背景下的地下裂缝型储层模型构建。然而，在地表露头中获取可靠的尺度化参数时存在显著不确定性，针对断层宽度与裂缝开度的参数估算尤为如此。这限制了我们将控制流体流动的关键参数从储层尺度向上外推至盆地尺度的能力。本研究公开了来自苏格兰凯斯内斯地区中泥盆统砂岩的9组一维断面（测线，scanline）断层与裂缝属性数据集，该区域被广泛用作设得兰群岛西部克莱尔油田等邻近地下储层的陆上类比体。本次多尺度分析证实，裂缝长度的幂律分布覆盖8个数量级（10⁻⁴ 至 10⁴），裂缝开度与断层宽度（含充填物）的幂律分布则覆盖4个数量级（10⁻⁶ 至 10⁻²）。本研究还公开了一套二维断层与裂缝拓扑分析数据集，可用于评估连通性与自相似性的非均质性。该多尺度方法为将露头类比中获取的微观至中观尺度裂缝属性向上外推至储层-盆地尺度，用于静态与动态储层模型提供了全新的理论依据。