Optimization of Child Well Hydraulic Fracturing Design: A Bakken Case Study

The combination of hydraulic fracturing and horizontal drilling unlocked a huge energy potential in the US. The unconventional plays have been developed by drilling several horizontal wells and hydraulically fracturing them to enhance the fluid flow. The implementation of these well can be done at the same time, known as Tank Development; however, due to the high capital expenditure and the increased risks associated with such an approach, in addition to the limited number of available drilling rigs. Operators try to hold the lease first by drilling one well, producing it, then extending the lease with additional wells. The challenge is that by producing from these wells, the stress and pore pressure state changes around the first wells (i.e., parent well). These changes directly affect the hydraulic fracture propagation from the offset wells (i.e., child wells). In this work, we build a numerical that represents a real case study. The model was calibrated using data from (a) Microseismic Depletion Delineation, (b) Microseismic events, (c) 10 years of production. Synthetic offset wells were implemented to run a sensitivity analysis on the well design (well spacing, cluster spacing, injection volume) and to understand how to design better wells that have been influenced by production from a primary well. The simulations were run for 10 years. The results show that wider well spacing results in better production, whereas lower cluster spacing had better production. This study allows operators to design better offset wells drilled next to a depleted parent well in the Bakken.