Impact of capillary pressure and flowback design on the clean up and productivity of hydraulically fractured tight gas wells

Abstract

This work analyses the impact of capillary pressure and flowback operational variables on hydraulically fractured tight gas wells with the objective of understanding the clean-up process at reservoir level and its impact on future well performance. Through numerical reservoir simulation, different scenarios were investigated, varying capillary pressure, flowback duration, shut-in duration and drawdown. These scenarios are interpreted with rate transient analysis. The results of this work show the ambivalent effect of capillary pressure in terms of facilitating imbibition but also holding back water close to the fracture. The novelty of this work consists in the findings that for lower capillary pressures, short shut-in periods lead to a better well productivity while for higher capillary pressure extended shut-in periods are better for well productivity. It was also found that drawdown can be used to minimize fracture face relative permeability damage and as shut-in period extends, flowback should be performed at smaller drawdowns. • Operational variables during a flowback operation of a tight gas well and its impact on well performance was analyzed. • Flowback should be designed to maximize well performance and not fracturing fluid recovery, unless 100% can be recovered. • Appropriate drawdowns can be selected during flowback to maximize well performance.