Resumen del autor, extraído del trabajo. The special rheological properties of waxy oil, appearing in a certain limited temperature rang, lays a rheological foundation bettering its low-temperature fluidity, and a series of specialized measuring techniques make it possible to obtain the accurate flowing parameters of waxy oil. The development on constitutive equations, and mathematical mode/software have pushed forward the pour point depressant (referred to PPD) technology to a general utilization in pipelines. Up to present, more than one dozen of pipelines have been under operation with the technique conducing safety and economy. Also, this technique has been successfully used in Sudan oil pipeline. Natural gas has gained an ascending proportion in buildup of energy consumption worldly. Chinese government has accordingly drawn up the relevant policy to promote gas industry. Most gas consumers are now in industrial cycles such as chemical and power supply etc. The gas consumption for civil use only accounts for a small portion. Now most of gas fields located in west of China, but the main gas user lie in east. The 10000-km gas trunk pipeline in existence is just at the initial stage. Base on the marketing trend and gas resources, China has worked out an ambitious plan to meet the requirements.