Numerical Simulations of Sand-Screen Performance in Standalone Applications

Abstract

The selection of optimum screens for standalone screen (SAS) applications has historically been based on experimental data, rules of thumb, or correlations. Recent sand-retention tests conducted in various laboratories offer empirical screen-selection criteria on the basis of different sand-size-distribution parameters. Unfortunately, these experiments have their own limitations. They provide substantially different results, depending on how the tests are conducted and interpreted, leading to significant differences in the recommended screen type and screen-opening size for any given sand sample. To resolve these inconsistencies and to understand the physics of the problem better, this paper presents 3D numerical simulations to evaluate the performance of wire-wrapped sand screens and ultimately to develop systematic screen-selection criteria.In this paper, a new method is presented to estimate the mass and size distribution of the solids produced through wire-wrap screens. The method uses the entire particle size distribution of the formation sand and is validated with experimental and numerical data. The new method allows us to evaluate the performance of different screens without running expensive and sometimes inconclusive experiments, enhances our understanding of screen performance, and helps to design sand screens better to meet performance criteria under a wide variety of conditions. We first present results from 3D, discrete-element computer simulations of sand screens placed in contact with granular sandpacks of approximately 100,000 particles. The numerical model computes the mass and the size distribution of the solids produced. The effect of the most important parameters, such as friction coefficient, fluid viscosity, pressure gradient, and ratio of screen-opening size to sand size, on the mechanism of bridge formation and amount of sand produced is studied using both monodispersed and polydispersed systems.The results have helped resolve some key questions about the physics of sand bridge formation. Numerous simulations are conducted to replicate the experimental conditions over a wide range of screen-opening/sand-size ratios for wire-wrap screens. Good agreement is observed between laboratory experiments and the simulations.

Evaluating the screen performance in sand control design by laboratory sand retention test

“…Có 2 loại thí nghiệm lưu giữ cát: kiểm tra lơ lửng (slurry test) và thí nghiệm gói cát (sand-pack test). Cả 2 thí nghiệm này đều có thể đo các thông số sau [6]: + Khối lượng cát thu được là 1 hàm của thời gian hoặc là hàm của khối lượng cát được bơm vào nhằm đánh giá hiệu quả giữ cát của lưới.…”

Numerical simulations of sand‐screen performance in unconsolidated prepacked gravel screen

“…Traditionally, the selection of mechanical sand screens relies on experimental data, general rules, or correlations. 20 The sand retention test (SRT) was a widely adopted approach for assessing the sand control performance and antiblocking capabilities of different sand control screens. [21][22][23] SRT tests are classified into three main groups: slurry SRT tests, prepacked SRT tests, and full-scale SRT tests.…”

“…These characteristics remarkably influence the performance of different sand control techniques. Traditionally, the selection of mechanical sand screens relies on experimental data, general rules, or correlations 20 . The sand retention test (SRT) was a widely adopted approach for assessing the sand control performance and antiblocking capabilities of different sand control screens 21–23 .…”