Hydraulic fracturing pumps fluid into fractures in rock bed in order to extract oil or gas. The chemical composition of fracturing fluids is dependent on the type of rock, the size of the fracture, and the fuel being extracted. Scientists with the Society of Petroleum Engineers developed a new hydraulic fracturing fluid designed to be used in low permeability tight gas wells (Gupta et al., 2009). After evaluating the chemical mixture based on its viscosity, foam generation, fluid loss, and conductivity, the scientists tested the fluid’s efficiency in a field study in the Greater Green River Basin, Wyoming. The results of this study were compared to similar treatments using conventional fluid, and the new fluid was found to have better initial and cumulative field production compared to standard hydraulic fracturing fluids.— Caitrin O’Brien
Gupta, D, Jackson, T, Hlavinka, G, Evans, J, Le, H, Batrashkin, A, Shaefer, 2009, M. Development and Field Application of a Low-pH, Efficient Fracturing Fluid for Tight Gas Fields in the Greater Green River Basin, Wyoming. Society of Petroleum Engineers, SPE Paper 116191, 602-610.
D.V.S. Gupta and his colleagues with the Society of Petroleum Engineers developed a new, low-pH fracturing fluid that is best suited for tight gas formations. Low-pH fluids have been shown to cause less permeability damage and better fracture cleanup in these formations than fluids with a higher pH. The newly developed hydraulic fracturing fluid is energized with N2 to create foam that can enhance the fluid recovery. This fluid also has a crosslink system, which is used to minimize friction and reduce the energy necessary to pump the highly viscous fluid. Gupta and his colleagues studied the new fluid’s viscosity by measuring how quickly the fluid traveled at different temperatures. The fluid’s foam capabilities were tested using a foam generator, and the fluid loss was tested at various temperatures. The scientists determined the fluid’s conductivity by measuring the time it took for a test proppant to move through a fake hydraulic fracture. After thoroughly testing the properties of the newly developed fracturing fluid, 20 wells in the Frontier formation in southwest Wyoming were stimulated with the new fluid. The productivity of these test wells was compared to that of other wells in the formation that utilize various conventional fracturing fluids.
The new low-pH, high yield fracturing fluid developed by Gupta and his colleagues is designed for optimal production in low permeability gas reservoirs. The fluid was found to have adequate viscosity to initiate and propagate the fracture, and the fluid effectively transported the proppant in the fracture. The foam produced by the fluid has reasonable stability compared to other types of fracturing fluid, and the lower polymer loadings in this fluid inflict less damage on the rock formation. The newly designed fluid was found to be very conductive and did not cause obvious damage to the fracture. The fluid was tested in the Frontier formation, a shale formation in southwest Wyoming, where the results were favorable. Wells stimulated with the new fluid were found to produce more gas than conventional low-pH and high-pH efficient fluid systems.