Active Well Defense in the Bakken: Case Study of a Ten-Well Frac Defense Project, McKenzie County, ND

Abstract

The effects of well interference between existing producing wells and newly stimulated wells (commonly known as "frac hits") are of growing concern as full-density development accelerates across all the North American shale plays. Strategies to mitigate the negative effects of such interference are becoming increasingly important as frac hits become more frequent. This case study presents a second-generation active well defense project involving four new wells and six offsetting legacy wells in the Bakken and Three Forks formations located in the North Fork Field, McKenzie County, ND. The operator has experienced numerous examples of stimulation interference in this field as its development operations have progressed into the full-density phase. Stimulation interference is defined as any increase in pressure occurring in a well as a result of stimulation activities in an offset or nearby well. While such interference has not necessarily had a lasting effect on legacy production, it has in some cases resulted in the need for costly remediation due to the migration of solids into the legacy laterals. The well defense efforts described herein are intended to minimize the need for post-stimulation remediation in legacy wells by preventing solids migration.

Huff-n-Puff Technology for Enhanced Oil Recovery in Shale/Tight Oil Reservoirs: Progress, Gaps, and Perspectives

“…The second method of protection was installing a packer to deal with high pressure, recharging offset wells with solvent, and refracturing the parent well before using hydraulic fracturing for the child well. Bommer and Bayne released a study that discussed the efficacy of active well defense, depending on water pumping process in the Bakken shales by preventing particles from moving into lateral portions. Scherz et al investigated well interactions and looked for fracture hits in Wolfcamp formations.…”

Effects of parent well spacing on the poroelastic behaviors in the infill zone in shale oil reservoirs: A case study in Jimsar Shale Oil, China

“…To poroelastically mitigate the negative impacts of parent well depletion on the infill zone, loading fluids in parent wells were identified as a possible strategy as the injected fluids partially recover the in situ stresses 24,25 . Field tests of this strategy in McKenzie County, North Dakota, proved its feasibility 26,27 . Huang et al 28 then established a correlation between reservoir depletion, fracturing, refracturing, and geological characteristics such as stress barriers in three‐dimensional modeling, where poroelasticity is an underlying controlling factor.…”

“…24,25 Field tests of this strategy in McKenzie County, North Dakota, proved its feasibility. 26,27 Huang et al 28 then established a correlation between reservoir depletion, fracturing, refracturing, and geological characteristics such as stress barriers in three-dimensional modeling, where poroelasticity is an underlying controlling factor. Poroelastic evolutions in the reservoir are correlated with the quality of hydraulic fracturing operations in infill zones.…”