1. Common Crude Oil Drag Reducer

As drag reducer, it is generally an oil soluble polymer with molecular weight ≥ 106. It is required to have good solubility, shear resistance, oxidation resistance, etc. Generally, the larger the molecular weight is, the worse the shear resistance is. There are short side chains in the molecule, which enhance the shear resistance. However, the side chain should not be too long, which makes the flexibility of the molecule worse and the drag reduction reduced. At present, drag reducers used at home and abroad include:

(polyisobutylene) (polymethacrylate) (polycyclopentadiene) (polystyrene) (polyalphene) (ethylene propylene copolymer)

Crude oil flow improver has been successfully applied in many oilfields at home and abroad. For example, adding flow improver 50mg / L to Zaire crude oil in West Africa reduces the freezing point of crude oil by 15.5 ℃; adding flow improver to Rotterdam Rhine pipeline in Europe transports Libyan crude oil, reduces the pour point of crude oil from 21 ℃ to - 14 ℃. The use of flow improvers in the land and subsea crude oil and product pipelines in the United States, Australia, the United Kingdom, Mexico, the Middle East and Southeast Asia has achieved good results.

The research of flow improver in China's oil field is late, but it has made rapid progress. For example, Zhongyuan Oilfield added 100 Mg/L flow improver polyacrylate can reduce the freezing point of crude oil from 30 ℃ to 7.5 ℃ and the viscosity by 97.5%; adding 100mg / L flow improver in Shengli oilfield can reduce the freezing point of crude oil from 30.5 ℃ to 10.5 ℃ and the viscosity by 93.5%; Changqing Oilfield began to use the flow improver of Exxon company of the United States in December 1988, which has a very significant effect on the Mahuining oil pipeline The line has become the first pipeline in China to realize normal temperature transportation throughout the year.

At present, the development trend of crude oil long-distance transportation technology is to use crude oil flow improver to realize normal temperature transportation. However, it should be noted that due to the different properties of crude oil in various oilfields, a flow improver can not be effective for each crude oil. Therefore, it is necessary to select suitable reagents through experiments. In addition, the flow improver only works when the crude oil begins to separate wax, so the temperature of adding agent should be the temperature when all wax in the crude oil dissolves, that is, the temperature of adding agent should be higher than that of separating wax. It should also be noted that flow improvers should not contain substances harmful to petroleum processing and product performance.