Production From a Fractured Well With Well Inflow Limited to Part of the Fracture Height

Abstract

Summary A study is presented on the production behavior of hydraulically fractured wells in which gas or oil in the fracture enters the wellbore over a limited vertical interval, smaller than the fracture height. Such a limited communication interval between fracture and wellbore can be expected when the fracture is created from a deviated or a partially perforated well. Type curves of the production behavior, derived with a numerical, single-phase simulator, show that in semiradial fractures with a limited communication interval, the early transient flow period exhibits the characteristics of a newly defined linear/radial flow regime. The characteristics of bilinear flow will be seen only when the fracture is in communication with the wellbore over the total fracture height. An analytical derivation of the pressure response during pure linear/radial flow is given, and an analysis method that is capable of estimating fracture conductivity, effective well inflow interval, and fracture height has been developed by making use of the characteristics of linear/radial flow. A small communication interval may also influence the long-term productivity of the well (especially a gas well) because of an increased non-Darcy flow effect near the communication interval. An expression for the expected skin value as a result of a limited communication interval is presented. The productivity of the well may be significantly reduced if the inflow interval is much smaller than the fracture height.