Development of unconventional reservoirs using multi-fractured horizontal wells (MFHWs) has led to closer well and hydraulic fracture spacing. Tighter placement of wells has led to increased instances of fracture interference. In addition to possible problems posed for development, fracture communication that persists during production complicates rate-transient analysis (RTA) because models/methods for RTA have mostly been applied to single-well production data. Availability of RTA methods specifically developed for communicating wells can reduce errors associated with hydraulic fracture and reservoir characterization and can lead to improved decision making.
A semianalytical method for history matching MFHWs communicating through hydraulic fractures has recently been developed using the dynamic drainage area (DDA) concept. In the current work, the DDA concept is employed to develop a new straight-line analysis (SLA) method for the transient linear flow regime that can be applied to two communicating MFHWs. The change in the drainage area of a single well due to communication challenges the use of the DDA concept. However, when the second well comes on production, reinitialization of the calculations for the first well helps to facilitate the implementation of the DDA concept.
The new DDA-corrected RTA (SLA) method for communicating wells is verified against the results of numerical simulation. Several synthetic cases are generated using numerical simulation to verify the accuracy of the developed method using various reservoir/fracture properties. The new method applied to the simulated cases allows estimation of xf within 10% of simulation model input. The DDA-corrected RTA method has also been applied to a field dataset, previously analyzed by the authors using the DDA approach to history match the well production data. This dataset consists of six wells, drilled from two adjacent pads, which exhibit strong well-pair communication. Application of this new RTA method to communicating well pairs results in xf estimates within 10% of those derived from model history matching.
In summary, a new straight-line (linear flow) analysis method is developed to analyze production data from communicating MFHWs. This new approach can help engineers quickly and accurately estimate reservoir and fracture properties in these scenarios. The method can therefore be used to improve hydraulic fracture design, well forecasting and development planning where persistent well communication through hydraulic fractures is occurring.