Abstract:
The resistivity of fracturing fluid used in shale gas hydraulic fracturing is low. During fracturing, the injection of large volume of fluid will result in a connected fracture network causing a reduction in bulk electrical resistivity, which can cause measurable EM amplitude anomaly on the surface. The time-frequency electromagnetic method collects data twice in the fracturing area before and after fracturing operation. The relative amplitude anomaly before and after fracturing can be used to predict and evaluate the spatial distribution of fracturing fluid. This paper introduces an example of using time-frequency electromagnetic method to monitor zipper fracturing. The relative amplitude anomaly before and after fracturing can reflect the vertical and horizontal distribution of fracturing fluid, which can be used to predict and evaluate the spatial distribution (length and height) of fracturing network and the fracturing effect of zipper fracturing.