A data analytics framework for analyzing the effect of frac hits on parent well production

Well interference, which is commonly referred to as frac hits, has become a significant factor affecting production in fractured horizontal shale wells with the increase in infill drilling in recent years. Today, there is still no clear understanding on how frac hits affect production. This work aims to develop a process to automatically identify the different types of frac hits and to determine the effects of stage-to-well distance and frac hit intensity on long-term parent well production. First, child well completions data and parent well pressure data are processed by a frac hit detection algorithm to automatically identify different frac hit intensities and duration within each stage. This algorithm classifies frac hits based on the magnitude of the differential pressure spikes. The frac stage to parent well distance is also calculated. Then, we compare the daily production trend before and after the frac hits to determine the severity of its influence on production. Finally, any evident correlations between the stage-to-well distance, frac hit intensity and production change are identified and investigated. In addition, this work also introduces a novel pressure integration approach to better understand the prolonged production effects of sustained frac hits. The methodology was to first characterize every induced pressure change in a parent well (i.e. to determine frac-hit intensity), and subsequently to estimate the average daily production change after each frac hit. This was accomplished by utilizing a frac hit auto-detection algorithm and a log-log analysis of daily production. To add the effect of interference time (i.e. the time of the pressure change caused by the frac hit), a “PCI” metric was calculated for each parent well. Finally, the effects of frac-hit intensity and interference time on parent well production were quantified through correlation analysis. This work utilizes 3 datasets covering 13 horizontal wells in the Bakken formation and 37 horizontal wells in the Eagle Ford Shale formation. These datasets included well trajectories, child well completions data, parent well pressure data and parent well production data. The data analysis results include factors influencing frac hit intensity and production responses to different types of frac hits. Also, the result shows that both frac hit intensity and interference time impacts parent well production. This work not only adds new understandings to frac hit study, but also challenges some of the previous work