Characterizing fracture and matrix heterogeneities in tight gas fields

Well performance is extremely variable in the stacked sequence of tight Devonian and Mississippian carbonates in the northern part of the Waterton complex of Alberta, Canada, despite an extensive fracture system present in all the wells. To determine why some wells penetrated more permeable fractures than others, a full reinterpretation of the geophysical, structural, stress, matrix and dynamic data sets was carried out at West Carbondale field in the complex. Flow simulations at sector scales using discrete fracture network models and full-field continuum modeling were used to test a range of geological and dynamic scenarios. For this field, the best-fit dynamic models consist of a major fracture zone, corresponding to either a seismic scale lineament or zone of enhanced curvature, trending through the area of most prolific wells. Outside this zone, the vast majority of the fracture system makes little contribution to flow in the wells.