Abstract <p>The aim of this work is to describe the design and application of a compact portable proton nuclear magnetic resonance (NMR) flow analyzer for manual and stationary rapid monitoring of crude oil and wastewater characteristics along production lines. The advantages of the NMR method and instruments based on it over the closest analogs are discussed. A brief overview of the theory of proton NMR relaxometry, the measurement technique, and the metrology of the method is given. The design and main components of the analyzer are described, as well as the technologies for representative sampling and instrument control. Correlations between hydrocarbon characteristics and proton NMR relaxation parameters were established to support the development of flow-based rapid monitoring technologies using these parameters. Equations were obtained linking proton NMR parameters with the properties of chemical products, including molecular weight and oil concentration in wastewater.</p>