Summer 2008
A New Alternative to Radioactive Tracers

For years, radioactive tracers have been the most common method used to gain insight about the height of propped fractures. Unfortunately, this tracer technology has many drawbacks such as the environmental and safety issues associated with using radioactive tracers as part of the fracturing treatment. Along with these issues, the growing regulations concerning the transportation of radioactive materials have had an impact on the use of this technology –especially in environmentally sensitive areas.

The primary issue with the use of radioactive tracers is the fact that they are constantly radioactive and considered a hazardous material. They must be transported, stored, handled, injected, and monitored in compliance with all the state, federal, and international regulations that apply. The application of radioactive tracers requires the addition of a tracer material to the proppant slurry as it is pumped into the well. This radioactive material must be properly dispensed by professional personnel trained to work with hazardous materials.

This technique also has other limitations, for example, the logging run has to occur soon after the fracturing treatment is completed to provide optimum detection. Results may be obtained for a limited time after placement, but typically not after 30 days.

PropTrac HSM is a more accurate method to optimize fracture treatments and improve results. The service uses Hexion’s resin coated proppants containing a non-radioactive tagging material in the coating. Once the well is fractured, these proppants are temporarily activated downhole with a specialized logging tool that identifies their precise location and determines propped fracture height.

The tag in the proppants has an extremely short duration response once it is activated downhole. Commonly used radioactive tracers are radioactive for weeks, while the new proppant tag is measured in minutes. PropTrac’s actived tag decays to non-detectable levels by the time the logging tool is removed from the well. The tag in the proppants only becomes detectable when it is actually activated during the logging run. A major benefit of this technique is that logs can be run repeatedly whenever they are required at the discretion of the operator – months, even years after the well is put into production. This is an invaluable source of information to determine downhole conditions during the entire life of the well.

Using this service gives you the added value of utilizing proppants that increase the fracture flow capacity (and well production) from the propped fracture. The tag added to the resin coated proppants does not change or reduce the effectiveness of the proppants in any way. These proppants are also just as safe for the environment and easy to handle as commonly used proppants.

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