The project goal is to develop a new method of stabilizing foams for frac fluids by adding surface-treated nanoparticles and/or surfactants to the liquid phase. The research will use commercially available or in-lab-modified nanoparticles and surfactants. The fracturing fluids will be those already employed in hydraulic fracturing: carbon dioxide [CO2], nitrogen [N2], and water.
The University of Texas at Austin, Austin, TX, 78712-0228
The rapid development of hydraulically fractured unconventional oil and gas reservoirs had made significant demands on water resources. A decisive advantage of foamed fluids is that they use substantially less water. Foamed fluids have been used 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. Nanoparticles with suitable surface coatings have several advantages specific to the application of foamed-fracturing fluids: they can stabilize viscous foams very for long periods to carry proppant; they are much smaller than pores in proppant packs, which allows them to be transported out of the reservoir during flowback; and their coating and concentration can be tuned to different fluid/fluid systems. Nanoparticles enable 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. Whereas foam (energized) fluids typically use about 20 to 40% water, the research team has introduced ultra dry CO2 and nitrogen foams with as little as 2 to 5% water by stabilizing the foams with nanoparticles and/or surfactants that viscosify the aqueous phase. Not only does the use of these energized fluids reduce water utilization and disposal, but it minimizes fluid blocking of hydrocarbon production.
This project seeks to demonstrate that suitably coated nanoparticles or viscoelastic surfactants can stabilize foams of fluids useful for hydraulic fracturing at elevated pressures and at temperatures ranging from ambient to reservoir conditions. The water-based foams require four to twenty times less water per barrel of fluid than conventional water-based fracturing 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. The technology 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.
The project was completed on September 30, 2017.
Final Report [PDF] December, 2017
Development of Nanoparticle-Stabilized Foams To Improve Performance of Water-less Hydraulic Fracturing (Aug 2017)
Presented by Keith Johnston, University of Texas at Austin, 2017 Carbon Storage and Oil and Natural Gas Technologies Review Meeting, Pittsburgh, PA
Development of Nanoparticle-Stabilized Foams To Improve Performance of Water-less Hydraulic Fracturing (Aug 2016)
Presented by Masa Prodanovic, University of Texas at Austin, 2016 Carbon Storage and Oil and Natural Gas Technologies Review Meeting, Pittsburgh, PA