Fracture-network analysis of the Latemar Platform (northern Italy): integrating outcrop studies to constrain the hydraulic properties of fractures in reservoir models

Abstract

Fractures in subsurface reservoirs are known to have significant impacts on reservoir productivity. Quantifying their importance, however, is challenged by limited subsurface observations, and intense computations for modelling and upscaling. In this paper, we present a workflow to construct and upscale fracture models based on outcrop studies in the Latemar carbonate platform (northern Italy). Fractures were first analysed to investigate their distinct characteristics throughout different sedimentological domains; that is, slope, margin and platform interior. Several fracture models were then built to represent different domains and were used to upscale fracture-network properties. Small-scale models were preferred to the reservoir-scale ones to enable multiple realizations and various sensitivity analyses in a time-efficient manner. The fracture characteristics of the Latemar Platform vary across different sedimentological domains. This variation results in a non-homogeneous permeability field that will influence flow behaviours. Fractures in the slope domain are typically tall but low in intensity, resulting in relatively low effective permeabilities. In the platform interior, smaller sizes of fractures combined with higher intensities give rise to higher effective permeabilities. In general, fracture intensities, aperture and their intrinsic permeability would have a significant impact on the permeability field. Fracture shape and orientations are more important in affecting the connectivity.

Discrete Fracture Network Modelling in a Naturally Fractured Carbonate Reservoir in the Jingbei Oilfield, China

“…However, it is difficult to characterise fractures properly because of their extremely heterogeneity and complexity features [2,3]. Geologists and engineers tried to use different types of data to describe the fractures, e.g., seismic attributes, geophysical logs, drilling cores, and outcrops [4,5].…”

Multiscale fracture network characterization and impact on flow: A case study on the Latemar carbonate platform

“…Boro et al . [] presented effective permeabilities for outcrop‐scale DFN models (20 × 20 m) of the Latemar based on the Oda method [ Oda , ], an analytical approach that assumes flow to occur only through the fracture network. We pursue more rigorous flow‐based simulations to quantify the role of fractures by using Discrete Fracture and Matrix (DFM) models.…”

Naturally fractured hydrocarbon reservoir simulation by elastic fracture modeling

“…They also proved that the higher the fracture intensity, the higher flow velocity. Boro et al (2014) presented a workflow to construct an upscaled fracture model based on outcrop studies in a carbonate platform. It is important to note that fractures in the outcrop might have been affected by surface processes like weathering and stress release.…”

“…Then, they coupled these domains to simulate groundwater flow in their case study. However, Boro et al (2014) stated that in general, fracture intensities, apertures and their intrinsic permeability would have more significant impact on the permeability of the field. Fracture shape and orientations are more important in affecting connectivity.…”