Horn River Group (HRG) shales are prime exploration targets. The shales form a 200m thick package of over-pressured, organic rich, siliceous mudrocks found at drilling depths between 2400–2700m. The gross thickness of the shale interval and the observed frac barriers within the shale package present a challenge for maximizing the stimulated rock volume when completing wells. Within Devon Canada, an exploration program was designed to evaluate reservoir complexity and heterogeneity, the ultimate goal being to optimize horizontal, vertical and lateral well placement while balancing recovery factor and capital costs.
Core and log data from vertical wells were analyzed to target optimal horizontal drilling zones for hydraulic fracture initiation and ease of drilling. Geomechanical log analysis supports the observation made from microseismic data that frac height growth through the frac barriers in the shale package happens preferentially depending upon the direction from which the fracture was initiated.