Evaluation of Gravel-Pack Completion Characteristics on the Performance of a Producing Well in an Iraqi Oil Field

Abstract

Sand production is one of the main completion challenges in weakly consolidated and friable producing formations because it can reduce well deliverability, accelerate equipment erosion, increase cleanout frequency, and shorten the productive life of the well. Gravel-pack completion is commonly applied as an effective sand-control technique; however, its hydraulic influence on well performance must be carefully evaluated because an improperly selected or poorly placed gravel pack may introduce additional near-wellbore pressure losses. This paper evaluates the effect of gravel-pack completion characteristics on the performance of a producing well in a selected Iraqi oil field while maintaining the confidentiality of field and well identification. The study integrates available field completion data, pressure-volume-temperature fluid properties, reservoir parameters, perforation data, tubing configuration, and gravel-pack design variables into a well-performance evaluation model. The inflow performance relationship was developed by separating the total pressure loss into reservoir, perforation, and gravel-pack components, while the vertical lift performance was obtained from pressure-traverse calculations through the production string. The operating point was determined from the IPR–VLP intersection, and sensitivity analysis was performed for gravel-pack permeability and gravel-filled tunnel length. The results show that the studied well has good reservoir deliverability, but completion-related restrictions, especially perforation damage, crushed-zone effects, and gravel-pack resistance, reduce the effective inflow performance. Increasing gravel-pack permeability improved the operating rate, with the best hydraulic response obtained in the high-permeability range. Reducing the gravel-filled tunnel length from 0.95 to 0.38 in increased the operating rate from approximately 8398.6 to 8679.0 STB/day. These findings indicate that gravel-pack design should not be selected only according to sand-retention ability, but also according to hydraulic efficiency. A high-conductivity, properly placed gravel pack with minimum unnecessary flow-path length provides a better balance between sand control and well productivity.