The concept of infill well production degradation due to hydrocarbon production from primary wells is well established. Although operators have tried many approaches to combat and/or mitigate the effects of primary well depletion, none seem superior to the others. This case study will first review the primary completion performed in 2014 and how it influenced the infill wells drilled next to the primary well in 2016. The 2016 completion was performed prior to the advent of mitigation strategies, and the completion and production results for the 2016 infill wells raised awareness that there was an issue. As the company started to complete the remainder of the pad in 2020, with a 4-well development on the other side of the primary well, it was decided to try and use mitigation techniques that were available at that time.
The presentation will review the reason for the relatively large volume preload in the primary well (~50k bbl) and how it influenced the completion of the 2020 wells. To aid in analysis, downhole (DH) BHP gauges were installed in the 2014 & 2016 wells and DH microseismic analysis was performed using a vertical monitoring array in the primary well. Production results will be reviewed to gain an understanding of how the vintage completion designs compared to the modern style of completions. The presentation is expected to generate a spirited discussion on merits/demerits of some of the mitigation strategies.