In recent years successful stimulation and extraction of hydrocarbons from unconventional reservoirs has led to various approaches to the stimulation process. Slickwater stimulations pumped at very high flow rates have become the staple in formations such as the Barnett Shale. High treatment rates are made possible by the implementation of low dosages of polyacrylamide, which lower the effective pipe friction. This type of treatment process is common among other shale and tight gas plays throughout North America. Other types of treatments include conventional crosslinked or linear gelled fluids. Some treatments combine the conventional crosslinked fluids and the slickwater approach. Experimentation with multiple stimulation programs is a response to the changes in formation properties that vary from one formation to the next and within areas of the same formation. Over the last few years there have been several successful treatments implementing a high-quality foam stimulation in some shale formations. These treatments have usually included a gas phase in excess of 90 quality and often as high as 99 quality. This type of treatment is especially fitting for low-pressure reservoirs and in depleted zones. One advantage of a high-quality foam is its reduced environmental impact by using very small quantities of water as compared to high-rate slickwater stimulations. In these particular high-quality foams, a viscoelastic surfactant gel is used in the liquid phase as the gelling and foaming agent. With the combination of high-quality foam and non-damaging viscoelastic gel, the total fluid is completely non-damaging to the formation. Successful treatments in formations in the northeastern United States have led to a demand for use in other formations, necessitating a better understanding of fluid properties in order to design treatments. Very little published data is available for high-quality foam fluid properties. A study has been conducted to examine the fluid characteristics of high-quality foams as compared to typical 50 - 70 quality foams. This study will show trends of viscosity, foam stability and temperature sensitivity of high-quality foams using xanthan, guar-based gelling agents and viscoelastic base fluids.

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