Exploration and Production Technologies
 
Development of Nanoparticle-Stabilized Foams To Improve Performance of Water-less Hydraulic Fracturing Last Reviewed 12/23/2013

DE-FE0013723

Goal
The overall objective of this project is to develop a new method of stabilizing foams for frac fluids, namely, the addition of surface-treated nanoparticles to the liquid phase. The research will use fluids already employed in hydraulic fracturing (CO2, N2, water, and LPG) and commercially available nanoparticles.

Performer
The University of Texas at Austin, Austin, TX, 78712-0228

Background
The vast majority of hydraulic fracturing jobs are formulated with fresh water, and the use of water resources introduced by the rapidly growing development of unconventional oil and gas reservoirs is high. Foamed fluids for hydraulic fracturing have been used for more than forty years to improve flowback and cleanup after treatment, to improve stimulation performance by reducing leakoff rates, and to reduce fluid blocking of hydrocarbon production from the reservoir. A decisive advantage of foamed fluids is that they use substantially less water, thus making them easier to use for hydraulic fracturing would help reduce the demand for fresh water. Nanoparticles with suitable surface coatings have several advantages specific to the application of foamed frac fluids: they can stabilize foams very effectively and for long periods of time; they are small enough to stabilize small bubbles and hence enable large foam viscosities (needed for carrying proppant); they are much smaller than fracture widths and pores in proppant packs allowing them to be transported out of the reservoir during flowback; and their coating and concentration can be tuned to different fluid/fluid systems. Crucially, the mechanism by which nanoparticles stabilize foam differs from the mechanism for current technologies (i.e., surfactants and emulsifiers). This enables a potentially significant advance: foams can be generated that will carry proppant into a fracture but will break at a tunable threshold pressure after the stage is pumped and will not re-form in the proppant pack during flowback. These advantages would simplify the design and reliability of foamed frac jobs, thus reducing one of the obstacles to using less water for hydraulic fracturing.

Impact
This project seeks to demonstrate that suitably coated nanoparticles can stabilize foams of fluids useful for hydraulic fracturing (CO2 and water; N2 and water; N2 and LPG) at elevated pressures and at temperatures between ambient and reservoir. The water-based foams require four to to five times less water per barrel of fluid than conventional water-based frac fluids. The LPG foam would require no water and three to five times less LPG than current water-less fluids. Thus this research would have a significant impact on the development of unconventional oil and gas resources in areas where water use and/or disposal is constrained.

The results of this research will expand the options available to operators for hydraulic fracturing and can simplify the design and field implementation of foamed frac fluids. This technology, when developed, will make it easier for operators to switch to reduced-water or zero-water hydraulic fracturing campaigns, thereby alleviating one of the most sensitive challenges for domestic hydrocarbon production.

Accomplishments (most recent listed first)
The project was recently initiated.

Current Status (December 2013)
Project personnel will design and start construction of new apparatus for conducting foam generation/stabilization experiments with hydrocarbon liquids. They will test PEG-coated nanoparticles and dichlorodimethylsilane grafted silica nanoparticles for their ability to stabilize CO2-in-water foam and characterize the viscosity and quality (CO2 fraction) of the generated foam, with particular emphasis on the ability to stabilize viscous, very high quality foam to minimize water use.

Project Start: October 1, 2013
Project End: September 30, 2016

DOE Contribution: $1,089,660
Performer Contribution: $272,995

Contact Information:
NETL – Chandra Nautiyal (chandra.nautiyal@netl.doe.gov or 281-494-2488)
UT– Steven Bryant (steven_bryant@mail.utexas.edu or 512-471-3250)

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