Lab Services

Formation, Completion and Stimulation Fluid Compatibility Testing


Formation, completion and stimulation fluid compatibility testing is performed to:

  • provide data on the formation damage associated with a completion and/or stimulation fluid
  • provide an estimate of the regained permeability from damage mitigation and/or remediation techniques
  • provide data on the completion and/or stimulation fluid-formation interaction
  • provide data on the completion and/or stimulation fluid-proppant interaction

This testing is done to offer the completion engineer a look into the reservoir and wellbore interaction by contacting samples of actual reservoir rock with completion and stimulation fluids. These simulations evaluate the effect of treatment fluids, such as acids, mud filtrate and other fluids on flow capacity. The permeability of the core sample are measured and a comparison of the retained permeability before and after exposure to a treatment fluid allows an estimate to be made of the extent of formation damage a particular treatment may create.

Testing Equipment and Setup

The built for purpose formation and fluid compatibility 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 and temperatures as high as 300oF. The test cell is ported so that differential pressure transducers measure fluid pressures on either end of the core.

Sample Preparation

  • A cylindrical core sample (1-2 inches in diameter by 2-12 inches in length) in length is cut and endground flat.
  • The sample can be pre-saturated with an appropriate native or any desired fluid.
  • 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.
  • 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 the effective confining pressure and temperature and allow to equilibrate.
  • Establish flow with an inert fluid and measure base permeability.
  • Flow appropriate completion and/or fracturing fluid filtrate through the core.
  • Establish flow and measure retained permeability.
  • Repeat exposure to completion and/or fracturing fluid filtrate as appropriate measuring retained permeability.

Test Results, Calculations, and Reporting

Experimental results are represented as a plot of retained permeability. Also, displacement of the sample is measured (to an accuracy of 0.00001 inches) and reported. Results also include Scanning Electron Microscope (SEM) photographs showing the interaction between the core and the injected fluid.


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