Post-Frac Evaluation of Horizontal Wells Producing Shale/Tight Reservoirs with Early Flowback History

Abstract

The early flowback history of fracturing fluid can be used to evaluate the effect of multi-stage fracturing for horizontal wells, and the effective fracture pore volume is the critical parameter to reflect the fracturing effectiveness. However, the current calculation method of effective fracture pore volume based on the flowback history has the problem of low accuracy. This paper presents a new method for quantitatively calculating the effective fracture pore volume based on flowback history. It is based on the current available methodology in North America, using the flowing material balance method of Rate Transient Analysis (RTA), combined with the traditional production decline method. Taking a domestic tight oil multi-stage fracturing horizontal well as an example, The workflow of this new methodology is illustrated in detail. The calculation results show that only 21% of the injected fracturing fluid contributes to the fracture conductivity. The example results show that the new methodology can effectively improve the accuracy of the effective fracture pore volume.