Open Flow Area-Based Evaluation of Mechanical Sand Screens Using Advanced Image Analysis and Sand Retention Testing

Abstract This study presents a comprehensive laboratory investigation into the performance of mechanical sand screens, emphasizing the role of Open Flow Area (OFA) as a key parameter in enhancing sand screen evaluation accuracy. Utilizing an in-house Sand Retention Test (SRT) equipment, a series of experiments were conducted to replicate realistic downhole conditions, including drawdown pressures up to 1000 psi and increasing net confining pressures. Sand packs with varied particle size distributions (PSD) were compacted onto different screen types and tested to evaluate critical parameters such as initial screen permeability, sand production, flow rate, and retained permeability. A central innovation in this study is the comparison between conventional surface area-based calculations and OFA-derived permeability values for wire-wrapped screens (WWS) and premium mesh screens (PMS) with different nominal opening sizes. OFA was measured using high-resolution digital microscopy and grayscale image analysis, enabling accurate quantification of the actual flow-conductive regions of each screen. Results show that OFA-based calculations yield permeability and sand retention values that more reliably reflect screen performance under operational conditions. Screens with higher OFA consistently exhibited improved fluid flow and plugging resistance, even under elevated pressures. The findings highlight significant limitations in conventional approaches that rely on idealized cross-sectional areas, often leading to overestimations or underestimations of screen efficiency. By integrating OFA into the laboratory evaluation process, this study bridges the gap between laboratory testing and real-world sand control performance. The outcomes support the adoption of OFA as a design-sensitive metric for optimizing screen selection, improving sand control reliability, and minimizing formation damage in unconsolidated reservoirs.