Shale resource plays often present formidable reservoir management challenges, particularly with regard to capital utilization and allocation. In spite of significant measurement and analysis, uncertainty typically remains in the physical characteristics of the stimulated reservoir volume (SRV) accessed by hydraulic fracturing, namely: shale permeability, fracture spacing, SRV spatial dimensions, and gas-in-place. In order to assess the viability and the impact of business and development decisions, a consistent workflow for analyzing well performance and predicting future performance is needed.
In this study, well performance histories of several hundred wells spanning the Haynesville, Woodford, Barnett, Horn River, Marcellus, Fayetteville and Montney shale plays were investigated with a common and consistent analytical framework that determined: a) a well productivity measure during transient linear flow, b) completion pressure losses (between sandface and bottomhole), and c) the onset of intra-fracture interference (internal SRV depletion). Parameters determined from the analyses are key indicators of the combined result of reservoir quality and hydraulic fracture performance. Results of this multi-well cross-play study provide information about both inter- and intra-play variability and commonality.
In addition, the analytical methodologies used in this study provide a framework for diagnosing “problem well” performance issues. Several examples are presented, showing the likely effects of such things as poor fracture treatment results, frac hits from nearby wells and operational issues such as loss and gain of producing frac clusters.
The analytical approach utilized in this study can also be used to provide robust physics-based forecasts that directly recognize and incorporate interpretation non-uniqueness. Through a forecasting regimen that explicitly provides expected ranges of results, key field optimization decisions around well spacing and completion design can be made. Examples of this forecasting regimen demonstrate this capability.