Best Practices of Flowback and Deliverability Analysis in the Canadian Unconventional Montney for Enhanced Treatment Stage Design and Reservoir Characterization

Abstract

Abstract In September 2021, the Alberta Energy Regulator (AER) through a new pressure and deliverability testing directive issued new guidance for inline testing to align with the current practice for conducting these tests. Best practices of these techniques are presented for calculations for industry-submitted inline testing for flowback analysis and industry-submitted Absolute Open Flow deliverability analysis. Results are compared to previously published best practices in the Canadian Unconventional Montney. The new approach is based on obtaining dynamic fracture dimensions such as fracture half-length and height, conductivity, associated matrix permeability, and well productivity index estimates. This information is supporting evaluation on reserves and near wellbore communication. Analytical and numerical method descriptions are provided that has proven to have significant implications for treatment stage design and reservoir characterization. Complete governing equations are provided and flowback and deliverability techniques are described in detail to permit readers to replicate all results. 80 field case studies are presented for multi-stage hydraulic fractured horizontal wells in the Canadian Unconventional Montney. Comparisons are also provided for Inline testing and deliverability- derived productivity index. The most significant new findings are the variability of fracture dimensions, conductivity, matrix permeability and productivity index impacting reservoir characterization. This is important for well spacing and bench-related reserves assessment at the pad level. For AER it also means an enhancement on reserves assessment of the Montney for its flagship report ST-98 by conducting Rate Transient Analysis (RTA) using rate and bottom-hole pressure information. The findings have direct practical implications for operators in the Canadian Montney shale play and analogous shale plays in USA and elsewhere. Accurate production and pressure data is needed for calculating linear flow parameters, effective surface area, fracture length / height and for optimizing well spacing and frac design. It could be used for input for Rate Transient Analysis (RTA) for resources / reserves assessments in similar unconventional plays. The novelty of the new approach is in the ability to develop best practices in inline testing and analysis in the Canadian unconventional Montney, focus of significant short-term investment impacting royalties and solve non-uniqueness and/or uncertainty for well testing / completions/ production / reserves in reasonable time using the newly aligned engineering processes.