Friction Reducer Application History in Oilfield

The concept of drag reduction was first proprosed in the 1940s. In the early 20th century, firefighters in New York used water-soluble polymers to increase the flow of the drainage system. In 1948, a small amount of polymethyl methacrylate (PMMA) was dissolved in chlorobenzene, and the friction resistance could be reduced by about 50%. In the late 1960s, oil producers in the United States were able to use the drag reduction agent to transport and improve the delivery of crude oil pipelines across the Asga pipeline and it did a huge success. After that, the technology of drag reduction is further developed and widely used. In the 1980s, China also began to develop and test domestic anti-drag agents and carried out medium-sized tests on domestic crude oil pipelines. The performance of products had reached the level of foreign countries in the early 1970s. In recent years, the Petrochina Pipeline R&D Centerhas carried out the research work of drag reduction agent, and has obtained the success. The drag reduction agent series product performance has reached international level of similar products.

The oil base DRA is analyzed from its structure, most of which is a polymer with a flow chain or a long chain with fewer side chains. This polymer pure agent is a rubbery solid, usually dissolved in a solution of hydrocarbon (kerosene). 10% of the drag - reduction agent solution is very viscous viscoelastic. It is more difficult to flow and it can be drawn up very long silk. The polymer reducer can dissolve in crude oil or oil, but it is not soluble in water.  Andthe long chain is curled in the case of water . Drag reduction agent solution is of strong Newton. The viscosity under low shear rate is as high as 3000Pa.S and it does not decompose under 120 ℃.It is relatively stable.

Drag reduction is a special turbulence phenomenon. The drag reduction effect is a macroscopic manifestation of the effect of drag reduction on the turbulent field. It's a purely physical function. The molecules of drag reduction agents and the molecules of oil do not interact, nor do they affect the chemical properties of oil products, but they are closely related to the flow characteristics. In the turbulent flow, the motion velocity of the fluid particle is randomly changing, forming large or small vortexes. And the large scale vortex absorbs energy from the fluid to deform, break, and transform to a small vortex. The small scale vortex is also known as dissipative vortex, which is weakened and subsided under theaction of viscous force. The energy it carries is converted into heat and dissipates. Due to the shear stress and viscous force of the pipe wall, this transformation is more serious in the boundary layer of the near pipe wall .

After drag reduction agent is added to the pipeline, the drag reduction agent in continuous phase disperses in the fluid. By its viscoelastic characteristic, the molecular long chain shapes downstream to the natural flow and the microelement directly affects the fluid macroelements. The radial force from the fluid microelement acts on the microelement of the drag reduction agent distorts and rotates the deformation. The gravity ofdrag reduction agent resist the above force and effect the fluid microelement, changing the direction and the size of the fluid macroelement, making part of the radial force is converted to parallel to the axial force, thereby reducing the busywork consumes. On the macro, it obtained the effect of reducing friction loss.