Abstract. Natural fracture network characteristics can be establishes from high-resolution
outcrop images acquired from drone and photogrammetry. Such images might
also be good analogues of subsurface naturally fractured reservoirs and can
be used to make predictions of the fracture geometry and efficiency at
depth. However, even when supplementing fractured reservoir models with
outcrop data, gaps will remain in the model and fracture network
extrapolation methods are required. In this paper we used fracture networks
interpreted from two outcrops from the Apodi area, Brazil, to present a
revised and innovative method of fracture network geometry prediction using
the multiple-point statistics (MPS) method. The MPS method presented in this article uses a series of small synthetic
training images (TIs) representing the geological variability of fracture
parameters observed locally in the field. The TIs contain the statistical
characteristics of the network (i.e. orientation, spacing, length/height and
topology) and allow for the representation of a complex arrangement of fracture networks.
These images are flexible, as they can be simply sketched by the user. We proposed to simultaneously use a set of training images in specific
elementary zones of the Apodi outcrops in order to best replicate the
non-stationarity of the reference network. A sensitivity analysis was
conducted to emphasise the influence of the conditioning data, the
simulation parameters and the training images used. Fracture density
computations were performed on selected realisations and compared to the
reference outcrop fracture interpretation to qualitatively evaluate the
accuracy of our simulations. The method proposed here is adaptable in terms
of training images and probability maps to ensure that the geological complexity
in the simulation process is accounted for. It can be used on any type of
rock containing natural fractures in any kind of tectonic context. This
workflow can also be applied to the subsurface to predict the fracture
arrangement and fluid flow efficiency in water, geothermal or hydrocarbon
fractured reservoirs.