| dc.description.abstract | As exploration for oil and gas continues, it becomes necessary to produce from deeper formations that have low permeability and higher temperature. Unconventional shale formations utilize slickwater fracturing fluids due to the shale’s unique geomechanical properties. On the other hand, conventional formations require crosslinked fracturing fluids to properly enhance productivity.
Guar and its derivatives have a history of success in crosslinked hydraulic fracturing fluids. However, they require higher polymer loading to withstand higher temperature environments. This leads to an increase in mixing time and additive requirements. Most importantly, due to the high polymer loading, they do not break completely and generate residual polymer fragments that can plug the formation and reduce fracture conductivity significantly.
In this work, a new hybrid dual polymer hydraulic fracturing fluid is developed. The fluid will consist of a guar derivative and a polyacrylamide-based synthetic polymer. The polymer mixture solutions is prepared at a total polymer concentration of 20 to 40 lb/1,000 gal and at a volume ratio of 2:1, 1:1, and 1:2. The fluids are crosslinked with a metallic crosslinker and broken with an oxidizer at temperatures up to 400°F. Testing focuses on crosslinker to polymer ratio analysis to effectively lower loading while maintaining sufficient performance to carry proppant at this temperature. HP/HT rheometer will also be used to measure viscosity, storage modulus, and fluid breaking performance. HP/HT aging cell and HP/HT see-through cell will be utilized for proppant settling. FTIR, Cryo-SEM, and HP/HT rheometer will also be utilized to understand the polymer interactions. Results indicate that this new system is easily hydrated, requires fewer additives, can be mixed on the fly, and maintains excellent rheological performance at low polymer loadings.
Extensive experiments are conducted to evaluate the new dual polymer system. This system exhibits a positive interaction between polysaccharide and polyacrylamide families and generates excellent rheological properties. The major benefit of using a mixed polymer system is to reduce polymer loading. Lower loading is highly desirable because it reduces material cost, eases mixing and fluid preparation during the field operation, and potentially lowers damage to the fracture face, proppant pack, and formation. | en |
