Searching for the root cause of shale well rate variance: Highly variable fracture treatment response

Abstract

This case study highlights that shale wells drilled with tight well spacing in the same landing zone using the same fracture treatment plan, commonly show large variance in well productivity. Searching for the root cause(s) of this variance in performance, we conclude that the factory model – which assumes wells can be engineered in reproducible and identical ways – is not yet feasible in practice. For each well, largely similar fracture treatment schedules result in different fracture half lengths. Also, a significant proportion of perforations may fail to create any hydraulic fractures at all. This new reality means that underperforming wells in otherwise promising acreage are more likely an indication of varying fracture treatment response, rather than a result of poor source rock. Research focusing on the reduction of fracture treatment variance therefore deserves priority and may help steady the performance of future wells. • Shale wells drilled with factory model, commonly show large variance in well productivity. • Root cause(s) of well performance variance is researched. • Varying fracture treatment response is the main cause of underperforming wells. • Wolfcamp Formation gas and water ratios as a function of production time are discussed. • Each of the principal field development choices is briefly reviewed.