| dc.description.abstract | Hydraulic fracturing is high pressure injection of fracturing fluid, in order to
hydraulically crack open the rock in the area around the wellbore. The fracturing fluid used
enters the created fractures and essentially propagates fractures away from the wellbore when
fluid pressure is greater than the fracture pressure. Hydraulic fracturing fluids must include
thickeners to increase its viscosity, and breakers that degrade consequential fracturing fluid and
filter cake on fracture faces in order to avoid formation damage and regain fracture conductivity.
The purpose of this research is to detail the development of a self-breaking temporary
polymer gel system as a hydraulic fracturing fluid, Poly(vinyl alcohol)-Succinic Acid (PVA-SA)
+ Cr3+, without addition of internal breakers. First, PVA-SA is synthesized by the reaction of
PVA [poly(vinyl alcohol)] with SA (succinic anhydride) in Dimethylformamide (DMF), and
then slightly crosslinked with N, N'-Dicyclohexylcarbodiimide (DCC), catalyzed by 4-
Dimethylaminopyridine (DMAP) to produce PVA-SA-X; this is to increase its molecular weight,
prior to being crosslinked with a Cr3+ crosslinker to produce PVA-SA-X gel. Second, PVA-SA
and PVA-SA-X gel are characterized through rheological measurements, and analyzed for
concentration change response, temperature change response, and shear change response. Both
PVA-SA and PVA-SA-X gel prove to be shear-thinning fluids capable of proppant
suspendability and transport in conventional and unconventional hydraulic fracturing treatments,
respectively, due to its elevated viscosity, and solid-like and water-like behavior. Finally, the
degradation of PVA-SA-X and PVA-SA-X gel is tested without any internal breakers at different
temperatures, proving that at high temperatures of 95°C, low concentrations of this polymer
system is capable of self-breaking, minimizing formation and proppant-pack damage, posthydraulic
fracture treatment. | en |
