Integrating Fracture and Reservoir Modelling to Evaluate Fracture Geometry and Reservoir Performance – A Duvernay Case Study

Hydraulic fracture modelling and reservoir simulation modelling both have many benefits for understanding the performance of induced fractures and the reservoir. However, these modelling practices are rarely used together. By integrating these workflows, it enables a more comprehensive and accurate understanding of how both primary and complex induced fractures contribute to production. In this study, a Duvernay case history was investigated where fracture and compositional reservoir simulation were both applied as one integrated workflow.

Initially the two workflows were conducted independently. The complete pumping schedule was used in a fracture simulator to predict the number, size, shape, and conductivity of the hydraulic fractures. To properly characterize reservoir flow with a gas-condensate fluid system having complex phase behaviour, a compositional reservoir simulator was required. The reservoir simulation model was history matched against field production data to determine which fractures were contributing to production. Following the history match, new fracture designs were evaluated in the fracture treatment software to better improve cluster and stimulation efficiency. These second- generation optimized fracturing treatment designs were then evaluated in the reservoir model in an iterative process to determine the impact more accurately on production rates, decline curves, and resulting cumulative production.

While fracture modelling provided detailed predictive capability for fracturing treatment design, compositional reservoir production matching contributed a new level of understanding to determine which fractures were contributing to production. The use of reservoir modelling for production matching provided a methodology of reverse engineering the most likely average values for fracture half length, number of effective fractures contributing to flow, and fracture conductivity. A new optimal fracture treatment design was developed by designing it in the fracturing software and evaluating the performance in the reservoir simulator.

This integrated workflow provides insights into limitations of the fracturing treatment design pumped, and what further predictive fracture modelling should be undertaken to further optimize future treatments. The net result provides operators with a new opportunity for increased production and profitability.