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

Test setup:

  • Preparation of the screen element test sample, installation of the sample in the test chamber. 
  • Determination of sample permeability on clean oil
  • Switching the pump to the slurry line, formation of a Sand Pack on the coupon at a constant pressure drawdown of 200 psi
  • Fluid flow rate control
  • Collection of particles that have passed through the coupon to analyze the concentration and mass of particles produced. 
  • When the sand pack/crust height of 0.5″ is reached, increase the compaction line pressure to 1200 psi to create a simulated overburden pressure. 
  • Determination of samples plus sand pack permeability by clean oil pressurization at a Constant Pressure Drawdown of 200 psi
  • Removing the sand pack and measuring the retained permeability of the sample. 

Slurry/Prepack SRT setup concept design

The result of the test is:

  • The amount of formation material that passed through the screen
  • The retained permeability of the screen
  • The size of the particles produced through the screen

Two basic criteria are used to determine the optimal screen clearance

  • Hodge criterion (Hodge, et al, in SPE 73772): produced solids greater than 0.12 lb/ft2 of formation sand. 
  • Screen Retained Permeability 50% or greater

This site uses cookies to store data. 
By continuing to use the site, you consent to the use of these cookies.

This site uses cookies to store data. 
By continuing to use the site, you consent to the use of these cookies.