Fracture Conductivity Effect in DFN Modelling Using Carbonate Outcrop Data

Abstract

Synthetic well testing is an important tool which can be utilised to understand the fractures’ influence on flow behaviour. Different fracture sets have been used to identify the well performance and the conductivity of the fracture network. Five models were built using outcrop fracture data sets with similar statistical properties, and their flow performances were analysed using the well-test response to evaluate the outcrop-related uncertainties. The results of the aforementioned scenarios have shown remarkable differences in the pressure responses related to the degrees of fracture conductivity in each fracture set. This variation in the pressure response indicates that the higher fracture density may not necessarily result in a higher fracture conductivity. The fracture conductivity effect was further investigated using a scenario of a producer completed in a matrix block trapped within fractures. The results have referred that the distance to the fracture and the fracture conductivity have a considerable influence on the dual-porosity signature, which may mask the radial flow response of the matrix in the derivative plot when the fractures are very close. The outcome of this work can be used to understand the outcrop-related uncertainties as a pre-work of a full field fracture modelling and to calibrate the fracture conductivity at the well vicinity to improve the history matching. The results can also help in well-test interpretations when a similar pattern of pressure response is obtained from real well-test data.