Discrimination of Induced and Natural Fractures in Deep Boreholes (DINaF)

2021-2023: funded by the FFG

Project Leader:

Kurt Decker (University of Vienna)

Principal Investigators:

Mario Habermüller (University of Vienna)
Martin Schöpfer (University of Vienna)

Industry Partner:

NiMBUC Geoscience




The DINAF project focuses on the analysis of rock fractures detected in boreholes and on the development of discrimination criteria of fracture types for numerous subsurface applications.

The geological exploration of the deep underground relies routinely on borehole measurements as a key source for characterizing the subsurface conditions. Information retrieved from boreholes is of paramount importance for generating realistic models of the subsurface, which are used for a wide range of applications in the natural resources and geothermal industries, as well as in engineering and for underground storage.

In boreholes the observed geometries of natural and induced fractures can be very similar, hence the discrimination of these fracture types may be difficult. Misinterpretations of natural fractures as induced fractures, or vice versa, are a common problem, leading to serious errors in the characterization of reservoirs as well as in the assessment of the in-situ stress field.


This project aims at analysing borehole and core data with the following scope:

  • Characterize fracture morphologies in-situ in the boreholes and ex-situ on core data.
  • Discriminate natural from induced fractures by integrating core and borehole data. Identify ambiguous zones where a unique classification of fractures (as either induced or natural) is not possible.
  • Reproduce observed fracture morphologies by numerical modelling with the aim of understanding the processes causing the fractures. Numerical modelling involves full characterisation of the stress field and mechanical rock properties.
  • Establish guidelines and methods for the future fracture analysis of borehole data.

Borehole image log with oriented core goniometry log

Borehole image log (FMI) with oriented core goniometry log (left image) and core detail (right photo) illustrating natural and drilling induced (hydraulic) fractures. All borehole data courtesy of NAGRA.

Numerically modelled Hydraulic Fracture

A numerically modelled hydraulic fracture that initiated and propagated due to excess mud weight. ‘Cracks’ are coloured for aperture. Note that the maximum horizontal stress orientation is parallel to the x-direction. The borehole wall is plotted as a yellow cylinder. Model designed and run by Martin Schöpfer using the PFC3D software.