In the field of oil and gas exploitation, hydraulic fracturing is a core technology for activating low-permeability reservoirs and improving crude oil recovery efficiency. In principle, special fracturing fluid is injected into underground oil formations under high pressure to compress rock strata and form artificial fractures. Support agents are then used to prop open these fractures, enabling the smooth flow of deeply buried oil and gas. The performance of fracturing fluid directly determines the success of fracturing operations. As a critical additive for optimizing fracturing fluid performance and achieving efficient thickening, polyacrylamide (PAM) serves as an indispensable behind-the-scenes helper for oilfield fracturing.
Polyacrylamide is a water-soluble high-molecular polymer, and its unique molecular structure underpins its excellent thickening mechanism. Featuring long and slender molecular chains with active functional groups, PAM fully stretches and diffuses after dissolving in water. It forms a three-dimensional network structure through molecular chain entanglement and hydrogen bonding, which significantly enhances the viscosity and viscoelasticity of aqueous solutions. Compared with conventional thickening materials, PAM delivers stable thickening performance. A small dosage can convert water-based fracturing fluid into a uniform viscous colloid, which is well adapted to the complex underground reservoir environment.
The thickening property of PAM provides multiple core advantages for fracturing operations. First, it achieves efficient proppant carrying. Untreated water-based fracturing fluid has extremely low viscosity and cannot carry proppants such as quartz sand, resulting in severe proppant sedimentation during transportation and failure to deliver proppants deep into fractures. PAM-thickened fracturing fluid possesses greatly improved suspension and carrying capacity, which can transport proppants uniformly to all positions of artificial fractures. This prevents fracture closure after pressure relief and establishes stable flow channels for oil and gas. Second, it optimizes fracture generation effects. The high-viscosity fracturing fluid can transmit ground high pressure stably and squeeze rock strata evenly, forming regular and well-connected fracture networks and effectively expanding the oil and gas drainage area.
In addition, the PAM thickening system has numerous practical engineering advantages. It exhibits excellent shear stability, temperature resistance and salt tolerance, maintaining stable viscosity and resisting rapid degradation under the high-temperature and high-salinity conditions of underground complex formations. Meanwhile, the thickened fracturing fluid reduces friction resistance during high-pressure pumping, lowering operational energy consumption and construction costs. After fracturing construction, the system can rapidly restore low viscosity via gel breaking treatment and flow back to the ground smoothly, with minimal residual content and negligible formation damage, balancing production efficiency and reservoir protection.
Compared with traditional thickening materials such as vegetable gum, PAM features higher thickening efficiency, lower dosage and more stable performance, suitable for most conventional and complex reservoir fracturing scenarios. Currently, relying on its superior comprehensive properties including thickening, proppant carrying and fluid loss control, PAM has been widely applied in hydraulic fracturing projects across major oilfields. It has become a vital additive for the efficient development of low-permeability oil and gas reservoirs and the improvement of oilfield productivity, providing strong technical support for efficient and green exploitation of oil and gas resources.