Improved Flow Regime Identification and Novel Scaling Approach to Construct Type Wells for Multiply-Fractured Horizontal Wells

This paper introduces a robust framework for applying multi-segment Arps production decline models, specifically for ultra-low-permeability resource development with multi-fractured horizontal wells. In contrast to the industry’s common use of two- or three-segment Arps models for production forecasting, this study outlines four distinct flow regimes: early ramp-up, transient flow with constant b, transition flow over a log cycle with continuously changing b, and boundary-dominated flow with constant b (typically 0.3 < b < 0.5). The methodology estimates the durations of these flow regimes and predicts their start and end times, significantly enhancing individual well forecast accuracy. Additionally, the paper suggests a simple approach to scale production histories from wells to common reference conditions, including average permeability in the stimulated reservoir volume, fracture half-length, stage spacing, and lateral length. It involves identifying transient flow end time, comparing observed and dimensionless rates in Wattenbarger’s solution. This technique adeptly handles variations among wells in a region, crucial for constructing representative type wells and minimizing uncertainty in statistical analyses. This is achieved by expressing transient linear flow variables in dimensionless terms, enabling the normalization of rate-time profiles to selected reference conditions, ultimately proving effective in constructing representative type-well production profiles from groups of analog wells. Determining the end of transient flow presents a challenge, with permeability estimates reflecting an average across fracture stages influenced by treatments introducing microfractures and re-opened natural fractures. We also advise caution in interpreting fracture half-length. Further research is needed to explore the impact of production from outside the stimulated reservoir volume, inter-well interference, and to validate scaling methods in other oil fields.