Drag reducer

The sand-carrying capacity of a drag reducer refers to its ability to carry proppants (such as quartz sand, ceramsite) in fluids (such as fracturing fluids, drilling fluids). 

It is one of the core indicators for evaluating the performance of drag reducers in fields such as oil and gas extraction and hydraulic engineering, especially in hydraulic fracturing operations. The quality of the sand - carrying capacity directly affects whether the proppants can be evenly distributed to the target area (such as fractures), and thus determines the engineering effects (such as oil and gas production, formation stability). 

The sand-carrying capacity of a drag reducer is a comprehensive reflection of its rheological properties (especially low - shear viscosity, yield value) and shear - response characteristics. The core is to find a dynamic balance between "drag reduction" and "sand - carrying". In practical applications, it is necessary to select a suitable drag reducer according to engineering requirements (such as well depth, temperature, type of proppant), and achieve the synergy of efficient sand - carrying and low - energy - consumption pumping through formula optimization.

With the increase of the viscosity of the fracturing fluid, the pipeline friction and the power loss of the pump also increase. In order to effectively utilize the efficiency of the pump and reduce the friction of the fracturing fluid, drag reducer in oilfield is usually carried out using the fracturing fluid. 

Commonly used drag reducer for water-based fracturing fluids include polyacrylamide and the derivatives of drag reducer, polyvinyl alcohol (PVA), vegetable gum and its derivatives and various cellulose derivatives.

This series of drag reducer include sand carrying of the drag reduction agent is high-molecular-weight linear polymers--polyacrylamide. 

During the synthesis process, hydrophilic groups are introduced into the main chain of drag reducer's molecules through a special production process, making sand carrying of the drag reduction agent more easily dispersed and dissolved in water and reducing friction; if an appropriate amount of polymer drag reducer is added to the water, the pumping friction can be reduced by more than 70% compared to the friction of clean water.

There are huge market share in drag reducing agent market and has two types of drag reducer:Sand carrying drag reducing agent & Acidification thickening liquid.

The core contradiction of drag reducers lies in the conflicting demands between "drag reduction" and "sand-carrying": 

Excessive pursuit of drag reduction (low viscosity) will result in insufficient sand-carrying capacity, causing the proppants to settle. 

Over-emphasis on sand-carrying (high viscosity) will increase the pumping resistance, leading to a sharp rise in energy consumption and even making construction impossible.