Schlumberger

Technical Paper: Optimization of Frac/Pack Completions Based on Field Experience

Society: SPE
Paper Number: 84263
Presentation Date: 2003
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Abstract

As the frac/pack technology continues to evolve, there are a number of topics that need more understanding and improvement. Some of these are: The estimation of correct closure pressure, which in turn leads to evaluation of the correct fluid efficiency, and ultimately leads to the design of the slurry schedule. In addition, a proper fluid selection criterion is critical to the placement of highly conductive propped fracture wings via tip screenout.

This paper describes the long strides that have been taken to address these areas. Special attention is given to skin data from build-up tests showing skin increasing with increase in kh. In essence the paper shows effective ways to lower the skin, and consequently increase production. This goal is accomplished by adjusting the design of the frac/pack slurry schedule to observation from field data and to numerical modeling of the fracturing process, and also, by considering the issues stated above. As a consequence, the paper shows that important steps to minimize the skin are to:

  • Design the fracturing fluids to suit the character of the fractures in soft formations where cooldown, fluid velocities, and fluid exposure time are important.
  • Use equilibrium method to fine-tune the closure pressure (and fluid efficiency) evaluation.
  • Clean and pack the perforations not aligned with the fracture.
  • Use diversion techniques to pack the entire reservoir.
  • Evaluate the packing efficiency with bottomhole gauge data (temperature and pressure) and/or radioactive tracers.

When these steps are meticulously followed, fracture performances with lower skins can be obtained as demonstrated in the case history.

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