US Patent 10267943 Monitoring hydrocarbon reservoirs using induced polarization effect

Some examples of monitoring hydrocarbon reservoirs using induced polarization effect includes inducing polarization in a subterranean zone using an induced polarization fluid. The subterranean zone includes first formations and second formations. A quantity of hydrocarbons in the first formations is greater than quantity of hydrocarbons in the second formations. The induced polarization data is obtained from the subterranean zone. A portion of the induced polarization data from the first formations is different from a portion of the induced polarization data from the second formations. The second formations in the subterranean zone are identified based on the obtained induced polarization data.