Predicting fluid flow in reservoirs: analysis of fracture clustering in outcrop analogues

Abstract

Researchers have used lacunarity, a parameter that quantifies scale-dependent clustering in patterns to distinguish fracture networks that belong to the same fractal system. Also, in a previous study, the authors showed that lacunarity is efficient in representing the connectivity and fluid flow in synthetic fractal-fracture models having a single fractal dimension. The objective of this research is to investigate if the concepts thus developed is applicable to outcrop analogues which are representative of sub-surface fractured reservoirs. A set of nested fracture networks belonging to a single fractal system but mapped at different scales and resolutions is considered in this study. Lacunarity and connectivity values of these maps are evaluated using geospatial data analysis techniques. Fracture continuum (FC) models are built from these fracture maps and a streamline simulator, TRACE3D is used to flow simulate these maps. Results show that, although, the fractal dimension of these maps is same, but there exist stubble differences in the values of lacunarity, percolation connectivity, and also the fluid recovery values. It is further noted that the clustering, connectivity, and fluid recovery values can be pairwise correlated very well for these natural fracture maps. Thus, the overall results indicate that connectivity in fracture maps and hence in turn their flow properties are controlled by lacunarity or scale-dependent clustering attributes. Therefore, there could be novel applicability of lacunarity parameter in calibrating discrete fracture network (DFN) models with respect to connectivity of natural fracture maps and prediction of flow behavior in fractured reservoirs. Thematic collection: This article is part of the Digitally enabled geoscience workflows: unlocking the power of our data collection available at: https://www.lyellcollection.org/topic/collections/digitally-enabled-geoscience-workflows

Experimental Study on Factors Affecting Oil Recovery in Sandstone-Buried Hill Superimposed Reservoirs

“…Due to their unique geological characteristics and relatively high oil reserves, these types of reservoirs have increasingly attracted attention. − The connectivity between reservoirs, the heterogeneity, and the strategy of development are the critical factors affecting the efficacy of reservoir exploitation. − Reservoir connectivity can be determined by comparing the differences in well logging curves across various strata between adjacent oil and water wells . It can also be assessed by introducing tracers and detecting their production within the same well group unit to understand the connectivity between injection and production wells. − Additionally, it can be conducted using data inversion methods. − Studies on the impact of interlayer heterogeneity and development methods on development effectiveness can utilize numerical simulations, physical simulations, and mechanistic research, among other strategies. − …”