Selection of Tracers Used in Guar Gum Fracturing Fluid

In oil and gas development, most often the reservoirs are fractured in staged fracturing manner, and all the fracturing fluids entering into each zone are flowed back together to the surface. This process can be used to assess the backflow of the fracturing fluid as a whole, and is incapable of assessing the backflow of fracturing fluid form each single zone. To assess the backflow of the fracturing fluid from each single zone, tracers are added to the fracturing fluid into each zone at certain concentrations. Then the backflow is sampled continuously to detect the concentration of tracers therein, and the efficiency of the backflow of each zone can thus be determined. Tracers used in this process should be compatible with the fracturing fluid. In a series of laboratory experiments, low molecular weight alcohols and inorganic ions is proved not suitable for use as tracers in guar gum fracturing fluids, two other substances, TA and TB, on the contrary, are compatible with the guar gum, and have low adsorption in most reservoir environments (indicating that their use will notaffect the concentration measurement at the surface.), and are suitable for use as tracers in guar gum fracturing fluid.