Python toolbox for fracture stratigraphy quantification and mechanical interface characterization

Modelling Discrete Fracture Networks (DFN) in naturally fractured reservoir (NFR) implies identifying and understanding the fracture spatial distribution and relationships to stratigraphic interfaces (crosscutting or abutment) in 3D. However, capturing fracture geometric parameters in the subsurface has always been a challenging task. To palliate the lack of data, and to better constrain modelling inputs, outcrop analogs are often used. While Simonson (1978) showed that mechanical contrasts at bed interfaces are essential to control fracture abutment, Cooke (2006) showed that bed/inter-bed thickness ratio is also an important parameter to account for.

Our goal is to predict fracture network geometry in stratified sedimentary rocks. To this purpose, we present a new original python toolbox. We performed an integrated approach that quantifies and automatically computes the bed interface’s compliance to let fractures go through (or not). Accounting for abutment, cross-cutting relations and bed thickness data, a compliance value is calculated for each interface using 1D scanline or 2D outcrop photograph. The process comprises (1) a field survey data or a digitized image (stratigraphy and fracture pattern) and (2) the processing of the data. First, we applied the method to existing classification and quantification from other authors as case study to check the feasibility of the code. Second, we applied the method to naturally fractured and stratified carbonates located in SE France and Centre Albania.