Advanced hydraulic fracturing has become a complex and investment intensive operation; hence, predicting its performance has become more important than ever. Robust prediction of production profiles for hydraulically fractured wells is imperative for optimizing the fracture scheme for productivity and determining completion economics. Various methods are currently being applied to modeling production after hydraulic fracturing treatments ranging from traditional analytical methods to semi-analytical and advanced numerical methods. A key requirement for any production modeling approach is the ability and flexibility to cope with uncertainty in fracture, reservoir and well properties to optimize fracture design.
In this study, we applied different modeling techniques to a range of fracture treatment scenarios and compared several real case studies and examples from the North Sea area. A number of factors had to be taken into account during the selection of a particular production modeling technique. These factors included considerations related to well type, fracture design, extent of geological and petrophysical properties, availability of data and ready reservoir models, and turnaround time. Multiple simulations generating multiple production profiles were carried out in most of the cases to support uncertainty bracketing and guide informed decision making even in areas extending to completions optimization.
The results reflect the need to curtail the use of simplified models and approaches when sufficient data is available or where data can be integrated to further reduce uncertainties on a case-by-case basis. On one hand, hydraulic fracturing treatment can be capital intensive while on the other hand, profitability is often a dynamic and changing parameter. Hence, longer term productivity benefits (post fracturing) require explicit and realistic pre-evaluation. Finally, the work highlights robust approaches for uncertainty handling within the production modeling workflow.