Optimizing Well Spacing Based on Parent Well Depletion Radius

Abstract

Abstract This study focuses on the optimization of child well spacing to mitigate fracture hits caused by hydraulic fracturing near depleted fractured rocks. Fracture hits lead to damage in the parent wells and significantly reduce the productivity of child wells due to the substantial loss of fracture fluids and proppant to the parent well. The reduction in child well productivity can exceed 50% and is influenced by well spacing and parent well(s) depletion time. To achieve this optimization, the study combines decline curve analysis (DCA) and reservoir volumetric calculations to estimate the depleted pore volume impacted by the parent well(s). This allows for the estimation of depletion radii for the parent wells. By analyzing production history in an actual field case, depletion radii for shale wells were estimated. The preliminary results indicated that child wells with spacing greater than the depletion radius of parent wells did not experience frac hits, in contrast to those within the depletion radius, and these findings were further confirmed through fracture-driven interactions (FDIs). By estimating the depletion radii of parent wells, this study presents a more efficient and cost-effective method for optimizing well spacing in unconventional reservoirs. This approach helps to avoid detrimental frac hits, minimize parent well damage, and improve the productivity of child wells, thus maximizing the overall performance of hydraulic fracturing operations near depleted fractured rocks.