Abstract:

Recently, several analytical (type-curve, flow-regime analysis and simulation) and empirical approaches have been introduced to match and forecast tight reservoir production.  The challenge is to develop routine techniques that can be used to forecast tight formation production, while adequately addressing the complex physics of the problem.

In this work we combine analytical and empirical methods (“hybrid” methods) for forecasting tight/shale gas reservoirs completed with multi-fractured horizontal wells.  Forecasting a homogenous completion (equal hydraulic fracture length) case using established analytical procedures for transient linear flow (pre fracture interference), combined with the Arps decline curve for late-time (boundary-dominated) flow is shown. Also examination of the heterogeneous completion (unequal hydraulic fracture length) case to establish the impact of heterogeneities on decline characteristics post fracture-interference.  Additionally, an innovative method for designing hydraulic fracture and well spacing is discussed. 

Also discussed will be, recent studies have shown that shale gas industry is incorrectly determining gas-in-place volumes in reservoirs with a large sorption capacity by not properly accounting for the volume occupied by the adsorbed phase.