Jose Chavarria, ConocoPhillips
Optimized artificial lift design requires a reliable understanding of a well inflow performance relationship (IPR) to estimate production potential under different operating conditions. However, IPR-based design is not commonly applied in unconventional developments because well productivity and reservoir pressure change over time, while the large number of wells and comparatively modest production per well can make detailed reservoir modeling impractical. As a result, artificial lift systems are often designed using simplified assumptions that favor speed and scalability over well-specific optimization.
This presentation introduces a practical methodology for estimating current and future Well productivity using easily available field data and a simplified reservoir depletion model. Flowing bottomhole pressure can be measured directly using downhole gauges (ESP), calculated (Gas Lift), or inferred (Rod Pumps). The primary challenge is estimating current reservoir pressure, which is required to calculate productivity index and characterize the well’s inflow performance.
The proposed methodology favors the use of fluid-level shot data to calibrate reservoir-pressure estimates. These estimates are then used to calibrate a simplified depletion model that describes the evolution of reservoir pressure over time. Combining the depletion model with flowing bottomhole pressure and production data enables the estimation of current productivity index and the projection of future inflow performance. Field data from the Delaware Basin will be used to demonstrate the application and viability of the methodology for unconventional wells. The resulting framework can support artificial lift optimization and provide a consistent basis for evaluating the potential economic impact of alternative lift methods.