Sand Retention Testing

Sand retention tests is one of the most promising areas of work for the SCL test lab. Sand retention tests are a practical tool for selecting screen slot clearance values. A related goal of this test is to maximize productive fluid flow and minimize sanding by selecting the optimal slot clearance. 

There are two types of sand retention test:

• Slurry SRT
• Gravel Prepack SRT

Both tests are performed on samples cut from the wire winding of the screen element. Both tests require the determination of sample permeability, taking into account the formation of a sand crust on the surface of the sample. The suspension test simulates the process of gradual formation, growth of the crust on the sample and analyzes the speed of its emergence. In the gravel prepack test, a crusted sand pack is initially placed on the coupon under test, simulating the process of formation rock collapse on the screen surface. There are no accepted standards for these two types of tests. 

Currently, our laboratory is working on the implementation of a variant of the gravel repacking test with elements of the suspension test. The construction of the Slurry/Prepack SRT stand includes the main elements:

• Two hydraulic lines: Clear Oil Line, Slurry Line
• Confining Stress Line
• Low volume oil pump 
• Shaker for preparing a homogeneous slurry
• Test camera with sample
• Snubber
• Scales for determining the mass of the leaked fluid
• Pressure sensors
• Shut-off valves, fittings 
• Data logging system