Lab Services

Fines Migration and Embedment Testing


Fines migration and embedment testing is performed to:

  • provide input for the completion and stimulation selection and design
  • provide input data to aid in the selection of gravel, proppant, and screens
  • provide data for determining conductivity lost due to embedment and fines invasion
  • As a component in Tip Screen-out (TSO) fracture design and post fracture productivity predictions

In a conventional test of fines migration, a cylindrical core sample is loaded axially and confining pressure varied to emulate field flow and shut-in conditions. At each confining pressure, flow is established and permeability measured. The test determines the effect of fines migration on retained permeability. Scanning Electron Microscope (SEM) photographs are used capture the interaction between the fines and the sample pore throats. These measurements can be conducted at in-situ temperature and pore pressure.

Testing Equipment and Setup

The built for purpose fines migration and embedment equipment, available at NSI Laboratories, is used to perform this type of testing. This equipment consists of a test cell capable of handling core plugs up to two inches in diameter and twelve inches in length. The test cell can simulate actual field conditions with confining pressures up to 10,000 psi (+/- 0.1 psi accuracy) and temperatures as high as 300oF (+/- 2 oF accuracy). The test cell is ported so that differential pressure transducers measure fluid pressures on either end of the core and an LVDT is used to measure the displacement to 0.00001 inches.

Sample Preparation

  • A cylindrical core sample (1-2 inches in diameter by 2-12 inches in length) in length is cut in half.
  • Proppant is placed between the two core wafers in the test cell.
  • The sample is jacketed and placed in the test cell between hardened stainless steel endcaps. The endcaps are ported to allow flow and the measurement of permeability.
  • The sample can be pre-saturated with an appropriate native or any desired fluid.
  • Independent control and monitoring of the confining pressure and temperature is maintained throughout the testing.


The procedures for conducting a formation fluid compatibility test are relatively standardized. The assembled sample and instrumentation fixtures are installed in a pressure vessel. After this, typical procedures might include the following steps:

  • Actuate the piston and apply the confining pressure to the sample.
  • Bring the sample to a set confining pressure and temperature and allow to equilibrate.
  • Establish flow with an inert fluid and measure base permeability.
  • Ramp confining pressure to simulate field drawdown conditions.
  • Establish flow with an inert fluid and measure retained permeability.
  • Reduce confining pressure to simulate typical field shut-in.
  • Establish flow with an inert fluid and measure retained permeability.
  • Continue to ramp confining pressure to emulate field conditions and measure the retained permeability from each step.

Test Results, Calculations, and Reporting

Experimental results are represented as a plot of retained permeability as a function of time and confining pressure. In addition, displacement of the sample is measured (to an accuracy of 0.00001 inches) and reported. Scanning Electron Microscope (SEM) photographs showing the interaction between the fines, embedment and the proppant are taken and presented.


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