Summary Hydraulic fractures play an important role in influencing gas production in shale formations. After the hydraulic fracturing treatment, the fracturing fluid will remain in the fractures, inducing water-rock interaction (WRI), which can soften fracture walls, reduce fracture width, and jeopardize fracture conductivity. Although the effects of WRI on fracture conductivity have been extensively studied, the effect of the WRI duration on the fracture conductivity, together with the well performance, has not been hitherto studied. To fill this gap, this study experimentally investigates the variations in fracture conductivity under different WRI durations and effective stress. Based on the experimental results, a new fracture conductivity model that incorporates the effect of WRI duration has been developed. This model incorporates a sensitivity coefficient that quantifies the effect of WRI duration on fracture closure, considering the varying effective stresses encountered in the reservoir. The model accounts for the effects of proppant embedment, proppant compaction, and Brinkman flow, which are critical in accurately predicting fracture conductivity under realistic reservoir conditions. Additionally, the model is applied to both a numerical reservoir model and a field case to study the effect of WRI on the well performance. WRI causes a sharp decline in both fracture width and conductivity, with the decline rate stabilizing after the WRI duration of 9 days. After 1,200 days of production, the effect of WRI on gas production fades off.
Bai et al. (2026) studied this question.