Provided are compositions containing a mixture of microcapsules and a bulk polymer, where the microcapsules have an oil field chemical contained within the microcapsules. The microcapsules can be present in a variety of configurations. The microcapsules contain a core or a micro-matrix containing the oil field chemicals. The core or micro-matrix can be surrounded by one or more polymeric shells, where each shell contains at least one polymer that affects the release of the oil field chemical from the composition. The compositions provide for the sustained release of an oil field chemical into fluid in an oil field reservoir over long periods of time. Also provided are methods of making the compositions and articles containing the compositions, along with methods are of tracing the movement of fluid in a hydrocarbon reservoir using the compositions, and methods of providing for the sustained release of oil field chemicals.