Comparison of class II injection well area of review requirements with area of evaluation for hydraulically fractured wells

Paper presented at Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY


Since 2010 the US Environmental Protection Agency (EPA) has been proposing plans to study, and has now initiated research regarding the potential impact of hydraulic fracturing processes on drinking water sources. Their work refers to an ‘Area of Evaluation’ around a hydraulically fractured well, inferring that the wells immediately around hydraulic fractured wells should be studied, to evaluate the conditions of these wells and their potential to contaminate overlying USDWs. Class II injection wells must have a minimum 1/4 mile radius area of review to determine the condition of wells surrounding the proposed injection well. All wells within this AOR are evaluated, although wells that intersect the zone of injection are of greatest interest. This study examines publically available micro seismic data for multi-stage hydraulic fractured horizontal wells in various shale plays. A 1/4 mile AOE is inscribed on each stage the microseismic to determine if all microseismic events fall within this criteria. The study also investigates current state practices with respect to AOE. Results of this study indicate that most wells have hydraulically fractures that fit within current 1/4 mile AOR criteria. While this may not be the only aspect to consider with respect to these types of wells, it is a good starting point for additional study