Abstract

Unconventional well frac hits, also known as Frac Driven Interactions (FDI), are well-to-well communication events initiated by hydraulic fracturing of an offset well. While some wells show production uplifts after a frac hit, many wells experience production degradation or complete loss of production due to failed casing or plugged up wellbores. This negative parent-child interaction presents challenges to Eagle Ford (EF) operators. As the EF matures with more infill development, the number of frac hit events is set to grow given the increased well density and large completion job sizes. This paper focuses on EF fracture hits (FH) characterization, production impact prediction methods and mitigation techniques.

With over 12 years of development in the Eagle Ford, we have collected a comprehensive dataset of frac hits and built an integrated database that incorporates frac hit timing, pressure responses, water/sand volume changes, short- to long-term production impacts, associated parent/child well completion and geological information. In-depth analysis has been conducted on extensive development across the EF. A new integrated workflow including empirical assessment, Multivariate Analysis (MVA) and mechanistic modeling was developed to identify key trends, study mechanisms and predict frac hit production impacts on parent wells. Various techniques have been explored and pilots tested in an effort to mitigate parent-child FH impacts.

The key frac hit impact drivers are identified as parent-child well distance and configuration, parent well depletion, completion design and geology. The models and workflows leveraged have improved the predictability of frac hit likelihood and their production impacts with mechanistic modeling providing insights to the physical process of a frac hit. Several mitigation techniques have been piloted with refracturing of the parent well, optimizing drill schedules to increase distance between infills and high-rate parents, as well as post-frac cleanouts proving effective in the study area.

The techniques and findings presented in this paper are intended to improve the understanding of frac hit trends and their impacts on unconventional development. The ideas presented may spark further research and development of improved mitigation techniques to combat this industry challenge.

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