Nodal Analysis-Based Modeling for Quantifying the Benefits of Compression in Low-Pressure Shale Gas Wells

Abstract

When shale gas reservoirs enter the low-pressure and low-production stage in their late life, surface compression is a key technique to enhance well performance. However, quantitatively predicting the effectiveness of this compression remains challenging. To address this, this paper derives a simplified Inflow Performance Relationship (IPR) formula tailored for shale gas wells, enabling rapid estimation of gas production under given reservoir and flowing bottom-hole pressures. A method is proposed to predict the instantaneous production increase by analyzing the shift in the nodal analysis point between the Tubing Performance Relationship (TPR) and IPR curves after compression, achieving a practical prediction accuracy of 80% to 96%. Furthermore, by analyzing the dynamic downward shift of the IPR curve with declining reservoir pressure, the study defines the effective period of production enhancement as the duration until the nodal analysis production rate returns to its pre-compression level. A predictive model for this effective period is developed by coupling this definition with an empirical relationship between cumulative gas production and reservoir pressure, which demonstrates a mere 4.2% error in field applications. This methodology provides direct and reliable technical support for optimizing production strategies and compression plans for low-pressure shale gas wells.