Modeling fracture connectivity in naturally fractured reservoirs: A case study in the Yanchang Formation, Ordos Basin, China

- A three-dimensional fracture network model is built using field outcrop data.
- A method for modelling fracture connectivity in shale gas reservoirs is proposed.
- Fracture connectivity in the Yanchang Formation is calculated based on the model.

This paper presents a method to model the connectivity between fractures in naturally fractured reservoirs. A three-dimensional discrete fracture network (DFN) model is generated and validated for a shale gas reservoir using field outcrop data collected from the Upper Triassic Yanchang Formation in the Ordos Basin, China. Based on the DFN model, connectivity parameters including the number of intersections per unit volume and the intersection length per unit volume are calculated. The results suggest that the mean fracture intersection length is 0.54 m. The number of intersections per unit volume and the intersection length per unit volume are 16 intersections/m3 and 8.58 m/m3, respectively. The self-intersection behavior and direction vector of the intersections are studied. The simulations show that the intersections between fracture sets 1 and 2 play a dominant role in the fracture intersections of the study area.