The effect of residual fracture fluid gels on the conductivity of propped fractures has commonly been measured in the laboratory with a static fracture conductivity procedure in which a certain amount of proppant is placed in a fracture conductivity cell, and then fracture fluid is injected into the cell. This test does not capture all of the physics of the process of proppant placement and fracture closure as it occurs in an actual fracturing treatment. In particular, the interactions among the transport of fracture fluid down the fracture and leakoff into the formation can result in a completely different distribution of residual polymer in the proppant pack in the real fracturing process compared with the static conductivity test.To more closely simulate actual fracturing conditions, we have developed a dynamic fracture conductivity procedure. In these experiments, fracture fluid/proppant slurry is injected into a fracture conductivity cell at injection rates representative of conditions in an actual fracture. Leakoff conditions are also set to mimic actual field rates. To be able to control leakoff at realistic rates, we use 3-inch thick core samples in the conductivity cell, rather than the 1/4 to 1/2 inch thick samples used in a standard API conductivity cell. After flowing the fracturing fluid slurry for some length of time, the cell is shut in, the fracture is closed by applying stress with a load frame, and then gas is flowed through the cell to represent the flowback period. During the gas flowback period, we repeatedly measure fracture conductivity to determine the amount of gel cleanup occurring.We have conducted a series of dynamic fracture conductivity experiments using a crosslinked guar-based fracture fluid at 150 ºF. One of the most significant findings is that the fracture conductivity measured with the same proppant loading using the static conductivity procedure is about twice as high as that obtained with a dynamic test. We also show how gel cleanup depends strongly on the gas flux through the fracture, on the presence of breaker, and on the polymer loading.