Sand particles are produced from the reservoir with low formation strength. A sand management system is required to be designed to keep the sand particles moving so as to prevent them from accumulating in the pipeline. Operating under unnecessarily high fluid velocities is not cost effective, moreover, it can lead to equipment failure; therefore, it is required to find the minimum velocity, known as critical sand deposition velocity, to keep the particles constantly moving.
In order to assess the critical sand deposition condition, a unique test facility was designed and constructed with 4-in ID PVC pipeline, which enables the pipe to be inclined 1.5° upward. Experiments were conducted with air-water-glass beads at low sand concentrations (< 10,000 ppm), and the air and water flow rates were selected to ensure stratified flow regime along the pipe. At constant superficial liquid velocity the gas velocity was reduced to find the critical sand deposition velocity.
The experimental results reveal that air-water flow regime plays an important role in particle transport; slug flow has high capability to transport particles at the pipe bottom, while the stratified flow has high risk of sand deposition. As long as the sand dunes are observed at the pipe bottom, the critical sand deposition velocities slightly increase with concentrations, while for stationary bed, the critical velocity increases exponentially with concentration.